Related Party Transactions [Abstract]
Schedule of amounts due from/to related parties
Schedule of Related Party Transactions [Table Text Block]
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Senior unsecured notes
Senior Unsecured Notes [Member]
Senior Unsecured Notes [Member]
Senior Unsecured Bonds
Senior Unsecured Bonds [Member]
Senior Unsecured Bonds
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
5.00% Senior unsecured notes maturing on August 15, 2018
Senior Unsecured Notes, Due August 15, 2018 [Member]
Represents senior unsecured notes bearing an interest rate of 5 percent maturing on August 15, 2018.
7.75% Senior unsecured notes maturing on March 15, 2020
Senior Unsecured Notes Due March 15, 2020 [Member]
Represents senior unsecured notes maturing on March 15, 2020.
4.50% Senior unsecured notes maturing on December 1, 2022
Senior Unsecured Notes Due December 1, 2022 [Member]
Represents senior unsecured notes bearing an interest rate of 4.50 percent maturing on December 1, 2022.
4.27% Senior unsecured notes maturing on December 17, 2025
Senior Unsecured Note Due December 17, 2025 [Member]
Senior Unsecured Note Due December 17, 2025 [Member]
4.50% Senior Unsecured Bonds Due December 2022
4.50 Percent Senior Unsecured Bonds Due December 2022 [Member]
4.50 Percent Senior Unsecured Bonds Due December 2022 [Member]
3.25 Percent Senior Unsecured Notes Due October 2022
3.25 Percent Senior Unsecured Notes Due October 2022 [Member]
3.25 Percent Senior Unsecured Notes Due October 2022
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Debt disclosures by scheduled maturity date
Debt Instrument, Information by Scheduled Maturity Date of Debt [Abstract]
-- None. No documentation exists for this element. --
Unpaid Principal Balance
Long-term Debt, Gross
Accreted Balance
Senior Notes
Deferred financing costs, net
Debt Issuance Costs, Net
Accreted Balance, net of deferred financing costs
Senior Notes, Net of Deferred Finance Costs
Senior Notes, Net of Deferred Finance Costs
Coupon Rate (as a percent)
Debt Instrument, Interest Rate, Stated Percentage
Initial Term (in Years)
Debt Instrument, Term
Face amount of loan
Debt Instrument, Face Amount
Redemption price, percentage
Debt Instrument, Redemption Price, Percentage
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of notional and fair value of derivative financial instruments and foreign currency hedges
Schedule of Derivative Instruments [Table Text Block]
Schedule of effect of derivative financial instruments on consolidated statements of income
Derivative Instruments, Gain (Loss) [Table Text Block]
Related Party [Axis]
Related Party [Axis]
Related Party [Domain]
Related Party [Domain]
Joint venture
Corporate Joint Venture [Member]
Variable Rate [Axis]
Variable Rate [Axis]
Variable Rate [Domain]
Variable Rate [Domain]
LIBOR
London Interbank Offered Rate (LIBOR) [Member]
Trust Preferred Securities
Junior Subordinated Debt [Member]
Mortgages and other loans payable
Mortgage and Other Loans Payable [Member]
Represents mortgage and other loans payable of the entity.
Revolving Credit Facility
Credit Facility 2012 [Member]
Represents information pertaining to 2012 Credit Facility.
Unsecured Term Loans
Term Loan [Member]
Represents the term loan of the reporting entity.
Senior Unsecured Notes
Senior Notes [Member]
Proceeds from issuance of debt
Proceeds from Issuance of Debt
Interest rate added to base rate (as a percent)
Debt Instrument, Basis Spread on Variable Rate
Scheduled Amortization
Future Amortization of Debt [Abstract]
-- None. No documentation exists for this element. --
Remaining 2018
Future Amortization of Debt, First Full Fiscal Year
The amount of amortization of debt expected to be recognized during the first full fiscal year following the date of the most recent balance sheet.
2019
Future Amortization of Debt, Second Full Fiscal Year
The amount of amortization of debt expected to be recognized during the second full fiscal year following the date of the most recent balance sheet.
2020
Future Amortization of Debt, Third Full Fiscal Year
The amount of amortization of debt expected to be recognized during the third full fiscal year following the date of the most recent balance sheet.
2021
Future Amortization of Debt Fourth Full Fiscal Year
The amount of amortization of debt expected to be recognized during the fourth full fiscal year following the date of the most recent balance sheet.
2022
Future Amortization of Debt Fifth Full Fiscal Year
The amount of amortization of debt expected to be recognized during the fifth full fiscal year following the date of the most recent balance sheet.
Thereafter
Future Amortization of Debt after Fifth Full Fiscal Year
The amount of amortization of debt expected to be recognized after the fifth full fiscal year following the date of the most recent balance sheet.
Total amortization of debt
Future Amortization of Debt
The total expected future amortization of debt.
Principal Repayments and Joint Venture Debt
Maturities of Long-term Debt [Abstract]
Remaining 2018
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months
2019
Long-term Debt, Maturities, Repayments of Principal in Year Two
2020
Long-term Debt, Maturities, Repayments of Principal in Year Three
2021
Long-term Debt, Maturities, Repayments of Principal in Year Four
2022
Long-term Debt, Maturities, Repayments of Principal in Year Five
Thereafter
Long-term Debt, Maturities, Repayments of Principal after Year Five
Total principal repayments
Long Term Debt, Maturities, Repayments of Principal
Total amount of long-term debt maturing in future periods.
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs
Deferred Financing and Leasing Costs Disclosure [Text Block]
Costs incurred in connection with financing activities (fees to banks) and costs incurred in connection with leasing activities (fees to real estate brokers), net of amortization.
Equity [Abstract]
Accumulated Other Comprehensive Income
Stockholders' Equity Note Disclosure [Text Block]
Stockholders' Equity Note [Abstract]
Stockholders Equity [Table]
Stockholders Equity [Table]
Disclosure of information pertaining to changes in stockholders' equity during the period.
Class of Stock [Axis]
Class of Stock [Axis]
Class of Stock [Domain]
Class of Stock [Domain]
Series I Preferred Stock
Series I Preferred Stock [Member]
Outstanding nonredeemable series I preferred stock or outstanding series I preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer.
Dividend Reinvestment and Stock Purchase Plan (DRIP)
Dividend Reinvestment and Stock Purchase Plan [Member]
Represents the dividend reinvestment and stock purchase plan of the entity.
Stockholders' Equity
Stockholders Equity [Line Items]
-- None. No documentation exists for this element. --
Preferred stock, shares outstanding (in shares)
Preferred Stock, Shares Outstanding
Dividend rate preferred units (as a percent)
Preferred Stock, Dividend Rate, Percentage
Perpetual preferred stock, liquidation preference (in dollars per share)
Preferred Stock, Liquidation Preference Per Share
Perpetual preferred stock, annual dividends per share (in dollars per share)
Preferred Stock, Dividend Rate, Per-Dollar-Amount
Contributions of net proceeds from sale of preferred stock
Proceeds from Issuance of Preferred Stock and Preference Stock
Common stock, shares authorized (in shares)
Common Stock, Shares Authorized
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interest
Schedule of Noncontrolling Interest [Table Text Block]
Tabular disclosure of the information pertaining to the noncontrolling interest.
Schedule of Preferred Unit Activity
Schedule of Preferred Units [Table Text Block]
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Business Acquisition [Axis]
Business Acquisition [Axis]
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
2 Herald Square
2 Herald Square [Member]
2 Herald Square [Member]
Property Acquisitions
Business Acquisition [Line Items]
Approximate Square Feet
Area of Real Estate Property
Acquisition price
Business Combination, Consideration Transferred
Business combination, fair value adjustment
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred
Schedule of calculation of numerator and denominator in earnings per unit
Schedule of Calculation of Numerator and Denominator in Earnings Per Unit [Table Text Block]
Schedule of Calculation of Numerator and Denominator in Earnings Per Unit [Table Text Block]
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Property Dispositions
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Schedule of reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Schedule of Income (Loss) Available to Common Stockholders [Table Text Block]
Tabular disclosure of the information pertaining to income (loss) attributable to common stockholders of the entity. This item may include reconciliation of income (loss) from continuing operations to net income (loss) attributable to common stockholders.
Accounting Policies [Abstract]
Schedule of Property, Plant and Equipment and Finite Lived Intangible Assets and Liabilities, by Major Class [Table]
Schedule of Property, Plant and Equipment and Finite Lived Intangible Assets and Liabilities, by Major Class [Table]
Table of long-lived, physical assets and finite lived intangible assets and liabilities that are used in the normal conduct of business to produce goods and services and which are not intended for resale.
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Domain]
Building
Building [Member]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Above-market leases
Above Market Leases [Member]
Below-market leases
Leases, Below Market [Member]
Leases, Below Market [Member]
In-place leases
In Place Leases [Member]
Represents information pertaining to in-place leases.
Investment in Commercial Real Estate Properties
Property, Plant and Equipment [Line Items]
Depreciable real estate reserves
Depreciable Real Estate Reserves, Effect on Earnings
Depreciable Real Estate Reserves, Effect on Earnings
Estimated useful life (in years)
Property, Plant and Equipment, Useful Life
Estimated useful life of other intangible assets (in years)
Finite-Lived Intangible Asset, Useful Life
Rental revenue from amortization of acquired leases
Rental Revenue Increase (Decrease) Acquired Lease Amortization
Represents the increase (decrease) in rental revenue during the period resulting from the net amortization of acquired above-market and below-market leases.
Reduction in interest expense from amortization of above-market rate mortgages
Interest Expense Increase (Decrease) Assumed Above Market Rate Mortgage Amortization
Represents the increase (decrease) in interest expense during the period resulting from the amortization of assumed above-market rate mortgages.
Identified intangible assets (included in other assets):
Finitely Lived Intangible Assets [Abstract]
-- None. No documentation exists for this element. --
Gross amount
Finite-Lived Intangible Assets, Gross
Accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Net
Finite-Lived Intangible Assets, Net
Identified intangible liabilities (included in deferred revenue):
Finite Lived Intangible Liabilities [Abstract]
-- None. No documentation exists for this element. --
Gross amount
Finite Lived Intangible Liabilities, Gross
Represents the gross carrying amounts before accumulated amortization as of the balance sheet date of all intangible liabilities having statutory or estimated useful lives.
Accumulated amortization
Finite Lived Intangible Liabilities, Accumulated Amortization
Represents the accumulated amount of amortization of a major finite-lived intangible liability class.
Net
Finite Lived Intangible Liabilities, Net
Represents the sum of gross carrying value of a major finite-lived intangible liability class, less accumulated amortization.
Net intangible assets reclassed to assets held for sale
Net Intangible Assets Transferred to Assets Held for Sale
Net Intangible Assets Transferred to Assets Held for Sale
Net intangible liabilities reclassed to liabilities relates to assets held for sale
Net Intangible Liabilities Transferred to Liabilities Related to Assets Held for Sale
Net Intangible Liabilities Transferred to Liabilities Related to Assets Held for Sale
Significant Accounting Policies
Significant Accounting Policies [Text Block]
Statement of Stockholders' Equity [Abstract]
Statement [Table]
Statement [Table]
Adjustments for New Accounting Pronouncements [Axis]
Adjustments for New Accounting Pronouncements [Axis]
Type of Adoption [Domain]
Type of Adoption [Domain]
Accounting Standards Update 2014-09
Accounting Standards Update 2014-09 [Member]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Preferred Stock
Preferred Stock [Member]
Common Stock
Common Stock [Member]
Additional Paid-In-Capital
Additional Paid-in Capital [Member]
Treasury Stock
Treasury Stock [Member]
Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Member]
Retained Earnings
Retained Earnings [Member]
Noncontrolling Interests
Noncontrolling Interest [Member]
Statement
Statement [Line Items]
Increase (Decrease) in Stockholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Beginning Balance (in shares)
Shares, Outstanding
Cumulative adjustment upon adoption of ASC 610-20
Cumulative Effect of New Accounting Principle in Period of Adoption
Adjusted Balance
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance
Net income
Profit (Loss) Less Minority Interest in Net Income (Loss) Operating Partnerships
Net income including minority interest in partnerships.
Other comprehensive income
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Preferred dividends
Dividends, Preferred Stock
DRSPP proceeds (in shares)
Stock Issued During Period, Shares, Dividend Reinvestment Plan
DRSPP proceeds
Stock Issued During Period, Value, Dividend Reinvestment Plan
Conversion of units of the Operating Partnership to common stock (in shares)
Stock Issued During Period, Shares, Conversion of Units
Conversion of units in the Operating Partnership for common stock
Stock Issued During Period, Value, Conversion of Units
Reallocation of noncontrolling interest in the Operating Partnership
Reallocation of Noncontrolling Interest to (from) Operating Partnership
Reallocation of Noncontrolling Interest to (from) Operating Partnership
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)
Deferred Compensation Plan and Stock Award, Shares
Number of shares issued during the period from a Deferred Compensation Plan and Stock Award.
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings
Deferred Compensation Plan and Stock Award, Net
Value of stock issued during the period from a deferred compensation plan and stock award, net.
Repurchases of common stock (in shares)
Treasury Stock, Shares, Acquired
Repurchases of common stock
Treasury Stock, Value, Acquired, Cost Method
Proceeds from stock options exercised (in shares)
Common Stock Issued During Period, Shares New Issues
This element represents the number of new common stock issued during the period.
Proceeds from stock options exercised
Common Stock Issued During Period, Value New Issues
This element represents the value of new common stock issued during the period.
Contributions to consolidated joint venture interests
Consolidation of Joint Venture Interest
This element represent the net income (loss) in consolidation of joint venture interest.
Deconsolidation of partially owned entity
Noncontrolling Interest, Decrease from Deconsolidation
Cash distributions to noncontrolling interests
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders
Cash distributions declared ($1.625 per common share, none of which represented a return of capital for federal income tax purposes)
Dividends, Common Stock
Ending Balance
Ending Balance (in shares)
Disposal Groups, Including Discontinued Operations [Table]
Disposal Groups, Including Discontinued Operations [Table]
Disposal Group Name [Axis]
Disposal Group Name [Axis]
Disposal Group Name [Domain]
Disposal Group Name [Domain]
600 Lexington Ave
600 Lexington Ave [Member]
600 Lexington Ave [Member]
115-117 Stevens Avenue
Stevens Avenue, 115 to 117 [Member]
Represents the information pertaining to 115-117 Stevens Avenue, a property owned by the entity.
635 Madison Avenue
Madison Avenue 635 [Member]
Madison Avenue 635 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Properties Sold [Abstract]
Properties Sold [Abstract]
Properties Sold [Abstract]
Sales Price
Disposal Group, Including Discontinued Operation, Consideration
Gain on Sale (Loss)
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax
Concentration Risk [Table]
Concentration Risk [Table]
1515 Broadway
Broadway, 1515 [Member]
Represents the information pertaining to 1515 Broadway, a property owned by the entity.
Accounting Standards Update 2017-05
Accounting Standards Update 2017-05 [Member]
Accounting Standards Update 2017-05 [Member]
Customer [Axis]
Customer [Axis]
Customer [Domain]
Customer [Domain]
Tenant 1
Tenant 1 [Member]
Represents first tenant of the entity for which a concentration risk is disclosed.
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
Concentration Risk Benchmark [Domain]
Annualized rent
Annualized Rent [Member]
Annualized rent, when it serves as a benchmark in a concentration of risk calculation.
Real Estate by Location [Axis]
Real Estate by Location [Axis]
Represents details pertaining to the locations of real estate properties of the entity.
Real Estate by Location [Domain]
Real Estate by Location [Domain]
Identifies real estate properties of the entity by location.
11 Madison Avenue
11 Madison Ave [Member]
11 Madison Ave [Member]
1185 Avenue of the Americas
Avenue of the Americas, 1185 [Member]
Represents the information pertaining to 1185 Avenue of the Americas, a property owned by the entity.
420 Lexington Avenue
Lexington Avenue, 420 [Member]
Represents the information pertaining to 420 Lexington Avenue, a property owned by the entity.
1 Madison Ave
1 Madison Ave [Member]
1 Madison Ave [Member]
Concentration Risk Type [Axis]
Concentration Risk Type [Axis]
Concentration Risk Type [Domain]
Concentration Risk Type [Domain]
Customer concentration
Customer Concentration Risk [Member]
Concentration of Credit Risk
Concentration Risk [Line Items]
Number of tenants (tenants)
Number of Tenants
Represents the number of tenants to whom the facility is leased.
Percentage of concentration (percent)
Concentration Risk, Percentage
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent) (more than)
Concentration Risk Percentage Threshold
Represents the maximum percentage of concentration risk that is not individually disclosed.
Gain on disposal
Cumulative Effect on Retained Earnings, Net of Tax
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Ownership Interests [Table]
Schedule of Ownership Interests [Table]
Represents information related to ownership interests held by the entity.
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event
Subsequent Event [Member]
Senior Unsecured Notes Due August 2021
Senior Unsecured Notes Due August 2021 [Member]
Senior Unsecured Notes Due August 2021 [Member]
Consolidated Entities [Axis]
Consolidated Entities [Axis]
Consolidated Entities [Domain]
Consolidated Entities [Domain]
SL Green Operating Partnership
Subsidiaries [Member]
Organization
Ownership Interests [Line Items]
-- None. No documentation exists for this element. --
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest
Noncontrolling interest in the operating partnership (as a percent)
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum rental payments for operating leases
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]
Schedule of future minimum rental payments for capital leases
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]
Class of Treasury Stock [Table]
Class of Treasury Stock [Table]
Share Repurchase Program [Axis]
Share Repurchase Program [Axis]
Share Repurchase Program [Domain]
Share Repurchase Program [Domain]
2016 Repurchase Program
2016 Repurchase Program [Member]
2016 Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Equity, Class of Treasury Stock [Line Items]
Authorized capital stock (shares)
Total Shares Authorized
The maximum number of total capital shares permitted to be issued by an entity's charter and bylaws.
Authorized shares, par value (in dollars per share)
Total Par or Stated Value Per Share
Face amount or stated value of capital stock per share; generally not indicative of the fair market value per share.
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Excess stock, shares authorized (shares)
Excess Stock, Shares Authorized
Excess stock, par value (in dollars per share)
Excess Stock, Par or Stated Value Per Share
Face amount or stated value of excess stock per share, which is generally not indicative of the fair market value per share.
Preferred stock, shares authorized (shares)
Preferred Stock, Shares Authorized
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Shares, outstanding (in shares)
Excess shares issued (shares)
Excess Stock, Shares Issued
Stock repurchase program, authorized amount
Stock Repurchase Program, Authorized Amount
Number of increases to share repurchase program
Share Repurchase Program, Number Of Increases To Share Repurchase Program
Share Repurchase Program, Number Of Increases To Share Repurchase Program
Shares repurchased
Stock Repurchased During Period, Shares
Average price paid per share (in dollars per share)
Treasury Stock Acquired, Average Cost Per Share
Maximum approximate dollar value of shares that may yet be purchased under the plan
Stock Repurchase Program, Remaining Authorized Repurchase Amount
Stock repurchase program, authorized amount
Stock Repurchase Program, Authorized Amount, Total
Stock Repurchase Program, Authorized Amount, Total
Repurchases of common stock (in shares)
Accumulated Other Comprehensive Income (Loss) [Table]
Accumulated Other Comprehensive Income (Loss) [Table]
Net unrealized (loss) gain on derivative instruments
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Net unrealized gain on marketable securities
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Other comprehensive (loss) income before reclassifications
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax
Amounts reclassified from accumulated other comprehensive income
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Deferred net losses from terminated hedges
Other Comprehensive Income (Loss), Deferred Net Loss from Terminated Hedges
Other Comprehensive Income (Loss), Deferred Net Loss from Terminated Hedges
Schedule of senior unsecured notes and other related disclosures by scheduled maturity date
Schedule of Long-term Debt Instruments [Table Text Block]
Schedule of combined aggregate principal maturities
Schedule of Maturities of Long-term Debt [Table Text Block]
Schedule of consolidated interest expense, excluding capitalized interest
Interest Income and Interest Expense Disclosure [Table Text Block]
Class of Treasury Stock
Class of Treasury Stock [Table Text Block]
Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments
Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments [Table Text Block]
Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments [Table Text Block]
Schedule of Earnings Per Share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Statement of Cash Flows [Abstract]
Operating Activities
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Adjustments to reconcile net income to net cash provided by operating activities:
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization
Depreciation, Depletion and Amortization
Equity in net income from unconsolidated joint ventures
Income (Loss) from Equity Method Investments
Distributions of cumulative earnings from unconsolidated joint ventures
Proceeds from Equity Method Investment, Distribution
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate
Equity Method Investment, Realized Gain (Loss) on Disposal
Purchase price and other fair value adjustments
Purchase Price, Fair Value Adjustment
Purchase Price, Fair Value Adjustment
Depreciable real estate reserves
Depreciable Real Estate Reserves, Cash Flow Effect
Depreciable Real Estate Reserves, Cash Flow Effect
(Gain) loss on sale of real estate, net
Gains (Losses) on Sales of Investment Real Estate
Gain on sale of investments in marketable securities
Marketable Securities, Gain (Loss), Cash Flow Effect
Marketable Securities, Gain (Loss), Cash Flow Effect
Deferred rents receivable
Straight Line Rent
Other non-cash adjustments
Other Noncash Income (Expense)
Changes in operating assets and liabilities:
Increase (Decrease) in Operating Capital [Abstract]
Tenant and other receivables
Increase (Decrease) in Accounts Receivable
Related party receivables
Increase (Decrease) in Due from Related Parties, Current
Deferred lease costs
Increase (Decrease) in Deferred Leasing Fees
Other assets
Increase (Decrease) in Other Operating Assets
Accounts payable, accrued expenses, other liabilities and security deposits
Increase (Decrease) in Accrued Liabilities and Other
The change during the period in carrying value of accounts payable, accrued expenses and fair value of hedges, due within one year or operating cycle.
Deferred revenue and land leases payable
Increase (Decrease) in Deferred Liabilities
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
Investing Activities
Net Cash Provided by (Used in) Investing Activities [Abstract]
Acquisitions of real estate property
Payments to Acquire Real Estate
Additions to land, buildings and improvements
Payments to Acquire Productive Assets
Acquisition deposits and deferred purchase price
Increase (Decrease) in Restricted Cash
Investments in unconsolidated joint ventures
Payments to Acquire Equity Method Investments
Distributions in excess of cumulative earnings from unconsolidated joint ventures
Proceeds from Equity Method Investment Dividends or Distributions
This item represents to disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation. Distributions constitute a return of investment.
Net proceeds from disposition of real estate/joint venture interest
Proceeds from Real Estate and Real Estate Joint Ventures
Proceeds from sale or redemption of marketable securities
Proceeds from Sale and Maturity of Marketable Securities
Other investments
Payments for (Proceeds from) Investments
Origination of debt and preferred equity investments
Payments to Acquire Investments
Repayments or redemption of debt and preferred equity investments
Proceeds from Sale and Maturity of Other Investments
Net cash provided by (used in) investing activities
Net Cash Provided by (Used in) Investing Activities
Financing Activities
Net Cash Provided by (Used in) Financing Activities [Abstract]
Proceeds from mortgages and other loans payable
Proceeds from Issuance of Secured Debt
Repayments of mortgages and other loans payable
Repayments of Secured Debt
Proceeds from revolving credit facility and senior unsecured notes
Proceeds from Other Debt
Repayments of revolving credit facility and senior unsecured notes
Repayments of Other Debt
Proceeds from stock options exercised and DRIP issuance
Proceeds from Stock Options Exercised
Repurchase of common stock
Payments for Repurchase of Common Stock
Redemption of preferred stock
Payments for Repurchase of Redeemable Preferred Stock
Distributions to noncontrolling interests in other partnerships
Distributions to Noncontrolling Interests Other Partnerships
The cash outflow for distributions to the entity's partner from a consolidated joint venture.
Contributions from noncontrolling interests in other partnerships
Proceeds from Noncontrolling Interests in Other Partnerships
The cash inflow from the capital received in cash from a partner in a consolidated partnership during the period.
Distributions to noncontrolling interests in the Operating Partnership
Distribution to Noncontrolling Interest Operating Partnership
The cash outflow for distributions to partners in a partnership.
Dividends / Distributions paid on common and preferred stock / units
Payments of Dividends
Other obligations related to loan participations
Proceeds from Participating Mortgage Loan
The cash inflow from participating mortgage loans and other mortgage obligations during the reporting period.
Tax withholdings related to restricted share awards
Payments Related to Tax Withholding for Share-based Compensation
Deferred loan costs and capitalized lease obligation
Deferred Loan Costs and Capitalized Lease Obligation
The net change during the reporting period in the finance costs incurred in connection with a loan. The capitalized lease obligation is a straight-line adjustment for ground lease obligations.
Net cash used in financing activities
Net Cash Provided by (Used in) Financing Activities
Net increase in cash, cash equivalents, and restricted cash
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
Cash, cash equivalents, and restricted cash at beginning of year
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash, cash equivalents, and restricted cash at end of period
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Conversion of units in the Operating Partnership for common stock
Partners' Capital Account, Redemptions
Tenant improvements and capital expenditures payable
Capital Expenditures Incurred but Not yet Paid
Fair value adjustment to noncontrolling interest in Operating Partnership
Operating Partnership Noncontrolling Interest Fair Value Adjustment
Represents the fair value adjustment to the noncontrolling interest in the operating partnership.
Deconsolidation of subsidiaries
Deconsolidation Real Estate Investments
Represents the change in the carrying value of real estate investments resulting from deconsolidation.
Transfer of assets related to assets held for sale
Transfer to Net Assets Held For Sale
Value of assets transferred to assets held-for-sale in noncash transactions during the reporting period.
Transfer of liabilities related to assets held for sale
Transfer to Liabilities Related to Net Assets Held For Sale
Value of liabilities transferred to liabilities related to assets held-for-sale in noncash transactions during the reporting period.
Removal of fully depreciated commercial real estate properties
Removal of Fully Depreciated Real Estate Assets
Removal of Fully Depreciated Real Estate Assets
Share repurchase payable
Share Repurchases Payable
Share Repurchases Payable
Bond repurchase payable
Bond Repurchase Payable
Bond Repurchase Payable
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value
Restricted cash
Restricted Cash and Cash Equivalents
Total cash, cash equivalents, and restricted cash
Statement of Financial Position [Abstract]
Assets
Assets [Abstract]
Commercial real estate properties, at cost:
Real Estate Investment Property, at Cost [Abstract]
Land and land interests
Land
Building and improvements
Investment Building and Building Improvements
Building leasehold and improvements
Building Leasehold Improvements, Gross
Carrying amount at the balance sheet date of long-lived, depreciable asset that is an addition or improvement to assets held under lease arrangement as well as the initial investment in a leasehold interest.
Properties under capital lease
Capital Leased Assets, Gross
Total commercial real estate properties, at cost
Real Estate Investment Property, at Cost
Less: accumulated depreciation
Real Estate Investment Property, Accumulated Depreciation
Total commercial real estate properties, net
Real Estate Investment Property, Net
Assets held for sale
Disposal Group, Including Discontinued Operation, Assets
Investments in marketable securities
Marketable Securities
Tenant and other receivables, net of allowance of $16,558 and $18,637 in 2018 and 2017, respectively
Accounts and Notes Receivable, Net
Related party receivables
Due from Related Parties
Deferred rents receivable, net of allowance of $15,776 and $17,207 in 2018 and 2017, respectively
Deferred Rent Receivables, Net
Debt and preferred equity investments, net of discounts and deferred origination fees of $23,216 and $25,507 in 2018 and 2017, respectively
Mortgage Loans on Real Estate, Commercial and Consumer, Net
Investments in unconsolidated joint ventures
Equity Method Investments
Deferred costs, net
Deferred Costs
Other assets
Other Assets
Total assets
Assets
Liabilities
Liabilities [Abstract]
Mortgages and other loans payable, net
Secured Debt
Revolving credit facility, net
Long-term Line of Credit
Unsecured term loan, net
Unsecured notes, net
Unsecured Debt
Accrued interest payable
Accrued Interest Payable and Other
Represents accrued interest and fair value of hedges entered into by the Entity.
Other liabilities
Other Liabilities
Accounts payable and accrued expenses
Accounts Payable and Accrued Liabilities
Deferred revenue
Deferred Revenue
Capital lease obligations
Capital Lease Obligations
Deferred land leases payable
Deferred Rent Credit
Dividend and distributions payable
Dividends Payable
Security deposits
Security Deposit Liability
Liabilities related to assets held for sale
Disposal Group, Including Discontinued Operation, Liabilities
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust
Total liabilities
Liabilities
Commitments and contingencies
Commitments and Contingencies
Noncontrolling interests in Operating Partnership
Noncontrolling Interest in Operating Partnerships
Limited partner interests in SLGOP (4,700 and 4,453 limited partner common units outstanding at June 30, 2018 and December 31, 2017, respectively)
Limited Partners' Capital Account
Preferred units
Temporary Equity, Carrying Amount, Attributable to Parent
Equity
Stockholders Equity Including Portion Attributable to Noncontrolling Interest in Other Partnership [Abstract]
-- None. No documentation exists for this element. --
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at both June 30, 2018 and December 31, 2017
Preferred Stock, Value, Issued
Common stock, $0.01 par value, 160,000 shares authorized and 86,780 and 93,858 issued and outstanding at June 30, 2018 and December 31, 2017, respectively (including 1,055 shares held in treasury at June 30, 2018 and December 31, 2017)
Common Stock, Value, Issued
Additional paid-in-capital
Additional Paid in Capital
Treasury stock at cost
Treasury Stock, Value
Accumulated other comprehensive income
Accumulated Other Comprehensive Income (Loss), Net of Tax
Retained earnings
Retained Earnings (Accumulated Deficit)
Total SL Green stockholders' equity
Stockholders' Equity Attributable to Parent
Noncontrolling interests in other partnerships
Other Noncontrolling Interests
Total equity
SL Green stockholders equity:
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Series I Preferred Units, $25.00 liquidation preference, 9,200 issued and outstanding at both June 30, 2018 and December 31, 2017
Preferred Units, Preferred Partners' Capital Accounts
SL Green partners' capital (904 and 973 general partner common units and 84,821 and 91,831 limited partner common units outstanding at June 30, 2018 and December 31, 2017, respectively)
General And Limited Partners Capital Account
General And Limited Partners Capital Account
Total SLGOP partners' capital
Partners' Capital
Noncontrolling interests in other partnerships
Partners' Capital Attributable to Noncontrolling Interest
Total capital
Partners' Capital, Including Portion Attributable to Noncontrolling Interest
Total liabilities and equity/capital
Liabilities and Equity
Series G Preferred Units
Series G Preferred Stock [Member]
Series F Preferred Units
Series F Preferred Stock [Member]
Series K Preferred Units
Series K Preferred Stock [Member]
Series K Preferred Stock [Member]
Series L Preferred Units
Series L Preferred Stock [Member]
Series L Preferred Stock [Member]
Series M Preferred Units
Series M Preferred Stock [Member]
Series M Preferred Stock [Member]
Series N Preferred Units
Series N Preferred Stock [Member]
Series N Preferred Stock [Member]
Series O Preferred Units
Series O Preferred Stock [Member]
Series O Preferred Stock [Member]
Series P Preferred Units
Series P Preferred Stock [Member]
Series P Preferred Stock [Member]
Series Q Preferred Units
Series Q Preferred Stock [Member]
Series Q Preferred Stock [Member]
Series R Preferred Units
Series R Preferred Stock [Member]
Series R Preferred Stock [Member]
Series S Preferred Units
Series S Preferred Stock [Member]
Series S Preferred Stock [Member]
Series T Preferred Units
Series T Preferred Units [Member]
Series T Preferred Units [Member]
Series U Preferred Units
Series U Preferred Units [Member]
Series U Preferred Units [Member]
Series A Preferred Units
Series A Preferred Stock [Member]
Series B Preferred Units
Series B Preferred Stock [Member]
Organization
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)
Minority Interest Units of Partnership Owned by Noncontrolling Owners
Represents the number of partnership units owned by the noncontrolling unit holders.
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares)
Common Stock Capital Shares Reserved Issuance upon Redemption of Units of Limited Partnership
Represents the number of common shares reserved for issuance upon redemption of units of the limited partnership interest.
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance at beginning of period
Distributions
Noncontrolling Interest, Decrease from Distributions to Other Noncontrolling Interest Holders
Noncontrolling Interest, Decrease from Distributions to Other Noncontrolling Interest Holders
Issuance of common units
Noncontrolling Interest, Increase from Subsidiary Equity Issuance
Redemption of common units
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests
Net income
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable
Accumulated other comprehensive income allocation
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest
Fair value adjustment
Minority Interest Increase (Decrease) from Fair Value Adjustment
Represents the increase (decrease) in noncontrolling interest resulting from fair value adjustments.
Balance at end of period
Number of preferred units issued (in shares)
Temporary Equity, Shares Issued
Liquidation preference of preferred units (in dollars per share)
Temporary Equity, Liquidation Preference Per Share
Annual dividends on preferred units (in dollars per share)
Preferred Stock, Dividends, Per Share, Cash Paid
Operating partnership common stock value use for conversion of preferred units (in dollars per share)
Operating Partnership Common Unit Value, Per Share Use for Conversion
Represents the common stock value per share which is used for purposes of determining the number of operating partnership common stock issue on conversion of preferred unit.
Number of company common stock issue on redemption of operation partnership common units
Operating Partnership Common Unit, Convertible Conversion Ratio
Operating Partnership Common Unit, Convertible Conversion Ratio
Mandatory liquidation preference (in dollars per share)
Temporary Equity, Liquidation Preference
Preferred units, shares authorized (in shares)
Preferred Units, Authorized
Number of company common stock issued on conversion of Series B preferred units
Preferred Stock, Convertible Conversion Ratio
Preferred Stock, Convertible Conversion Ratio
Investments, Debt and Equity Securities [Abstract]
Mortgage Loans on Real Estate Schedule [Table]
Mortgage Loans on Real Estate Schedule [Table]
Mortgage Loans on Real Estate, Loan Type [Axis]
Mortgage Loans on Real Estate, Loan Type [Axis]
Mortgage Loans on Real Estate, Loan Type [Domain]
Mortgage Loans on Real Estate, Loan Type [Domain]
Preferred Equity, April 2021
Preferred Equity, April 2021 [Member]
Preferred Equity, April 2021 [Member]
Preferred equity investments
Preferred Equity Investments in Mortgage Loans [Member]
Represents preferred equity investments in mortgage loans on real estate.
Preferred equity investment
Mortgage Loans on Real Estate [Line Items]
Aggregate weighted average current yield (as a percent)
Mortgage Loans on Real Estate, Interest Rate
Future Funding Obligations
Loans and Leases Receivable, Funding Obligation
Loans and Leases Receivable, Funding Obligation
Senior Financing
Mortgage Loans on Real Estate, Senior Debt on Investment
Amount as of the balance sheet date of debt which holds a position senior to the entity's investment in a mortgage loan on real estate.
Carrying Value
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Equity Method Investments [Table]
Schedule of Equity Method Investments [Table]
1274 Fifth Avenue
1274 Fifth Avenue [Member]
1274 Fifth Avenue [Member]
Stonehenge Portfolio
Stonehenge Portfolio [Member]
Stonehenge Portfolio [Member]
175-225 Third Street Brooklyn, New York
Third Street 175-225 [Member]
Third Street 175-225 [Member]
1745 Broadway
Broadway, 1745 [Member]
Represents the information pertaining to 1745 Broadway, a joint venture property of the entity.
Jericho Plaza
Jericho Plaza [Member]
Jericho Plaza [Member]
Investment, Name [Axis]
Investment, Name [Axis]
Investment, Name [Domain]
Investment, Name [Domain]
Preferred Equity due September 2018
Preferred Equity Due September 2018 [Member]
Preferred Equity Due September 2018 [Member]
Mezzanine loan due February 2022
Participating Financing Due February 2022 [Member]
Participating Financing Due February 2022 [Member]
Mezzanine loan due July 2036
Mezzanine Loan Due July 2036 [Member]
Mezzanine Loan Due July 2036 [Member]
Mezzanine Loan and Preferred Equity, Due March 2018
Mezzanine Loan And Preferred Equity, Due March 2018 [Member]
Mezzanine Loan And Preferred Equity, Due March 2018 [Member]
Mezzanine Loans And Preferred Equity [Member]
Mezzanine Loans And Preferred Equity [Member]
Mezzanine Loans And Preferred Equity [Member]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
Stonehenge Portfolio
Stonehenge Properties [Member]
Represents the information pertaining to Stonehenge Properties.
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Line Items]
Equity method investments
Ownership Interest
Equity Method Investment, Ownership Percentage
Gross Asset Valuation
Equity in net gain on sale of interest in unconsolidated joint venture/real estate
Noncontrolling Interests on the Company's Consolidated Financial Statements
Noncontrolling Interest Disclosure [Text Block]
Schedule of Related Party Transactions, by Related Party [Table]
Schedule of Related Party Transactions, by Related Party [Table]
One Vanderbilt
One Vanderbilt [Member]
One Vanderbilt [Member]
Alliance Building Services
Alliance Building Services [Member]
Represents the information pertaining to Alliance Building Services, which is a related party of the entity.
Entity with Stephen L Green ownership interest
Related Party Stephen L Green Interest [Member]
Represents the information pertaining to an entity in which Stephen L. Green owns an interest, which is a related party of the entity.
Marc Holliday
Investor [Member]
Andrew Mathias
Investor 2 [Member]
Investor 2 [Member]
Related Party Transactions
Related Party Transaction [Line Items]
Profit participation from related party
Related Party Transaction, Other Revenues from Transactions with Related Party
Payments made for services
Related Party Transaction, Expenses from Transactions with Related Party
Property management fees from related party
Revenue from Related Parties
Percentage of profits due to investors (as a percentage)
Related Party Transaction, Percentage of Profits Due to Investors
Related Party Transaction, Percentage of Profits Due to Investors
Due from related party
Related Party Transaction, Due from (to) Related Party
Amounts due from/to related parties
Due from Related Parties, Unclassified [Abstract]
Due from joint ventures
Due from Joint Ventures
Other
Due from Other Related Parties
Related party receivables
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Income taxes
Income Tax Disclosure [Abstract]
Federal, state and local tax provision
Income Tax Expense (Benefit)
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Award Type [Axis]
Award Type [Axis]
Equity Award [Domain]
Equity Award [Domain]
Stock options
Employee Stock Option [Member]
Restricted Stock Awards
Restricted Stock Awards [Member]
Represents the restricted stock awards granted by the entity. Restricted stock are shares of stock for which sale is contractually or governmentally restricted for a given period of time.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock available for issuance (shares)
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield (as a percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate
Expected life of option (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term
Risk-free interest rate (as a percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate
Expected stock price volatility (as a percent)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate
Options Outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance at beginning of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures
Exercised (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Lapsed or cancelled (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period
Balance at end of period (in shares)
Options exercisable at end of period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number
Total fair value of options granted during the period
Share Based Compensation Arrangement by Share Based Payment Award, Grants in Period Fair Value
Represents the weighted average fair value of awards granted during the period.
Weighted Average Exercise Price
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Exercise Price [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Exercise Price [Roll Forward]
Balance at beginning of year (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Granted (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Exercised (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Lapsed or cancelled (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price
Balance at end of period (in dollars per share)
Options exercisable at end of period (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price
Summary of restricted stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Balance at beginning of year (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Granted (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Cancelled (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Balance at end of period (in shares)
Vested during the period (in shares)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period
Partners' Capital of the Operating Partnership
Cash distribution declared, per common share (in dollars per share)
Common Stock, Dividends, Per Share, Declared
Corporate Indebtedness
Debt Disclosure [Text Block]
Schedule of commercial office properties
Schedule of Real Estate Properties [Table Text Block]
Investment in Unconsolidated Joint Ventures
Management fees, base revenue
Management Fees, Base Revenue
Assets (1)
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Commercial real estate property, net
Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance
Debt and preferred equity investments, net
Mortgage Loans On Real Estate Commercial And Consumer And Equity Method Investments Net
The balance represents the amount of loans that are secured by real estate mortgages, offset by any reserve to cover probable credit losses on the loan portfolio and deduction of deferred fees, unamortized costs, premiums and discounts from the face amounts. Included in this account is investment in unconsolidated joint venture which reflects the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.
Total assets
Equity Method Investment, Summarized Financial Information, Assets
Liabilities and equity (1)
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Deferred revenue/gain
Equity
Equity Method Investment Summarized Financial Information, Equity
Total liabilities and equity
Equity Method Investment, Summarized Financial Information, Liabilities and Equity
Company's investments in unconsolidated joint ventures
Combined statements of income for the unconsolidated joint ventures
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Total revenues
Equity Method Investment, Summarized Financial Information, Revenue
Operating expenses
Costs and Expenses
Ground rent
Direct Costs of Leased and Rented Property or Equipment
Real estate taxes
Real Estate Tax Expense
Interest expense, net of interest income
Interest Expense, Net
Amount of interest expense paid, net of interest income earned by the entity, during the period.
Amortization of deferred financing costs
Amortization of Debt Issuance Costs
Transaction related costs
Transaction Related Costs
This Element represents the transaction related costs during the period.
Depreciation and amortization
Depreciation, Depletion and Amortization, Nonproduction
Total expenses
Total Costs and Expenses Including Nonoperating Income (Expense)
This element represents the total of the costs related to real estate revenues, including management, leasing, and development services and income (expense) from ancillary business-related activities.
Net (loss) income before gain on sale (1)
Equity Method Investment, Summarized Financial Information, Net Income (Loss)
Company's equity in net income from unconsolidated joint ventures (1)
Document and Entity Information
-- None. No documentation exists for this element. --
Document Information [Table]
Document Information [Table]
Document Information [Line Items]
Document Information [Line Items]
Entity Registrant Name
Entity Registrant Name
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Entity Filer Category
Entity Filer Category
Document Type
Document Type
Document Period End Date
Document Period End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus (Q1,Q2,Q3,FY)
Document Fiscal Period Focus
Amendment Flag
Amendment Flag
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Counterparty Name [Axis]
Counterparty Name [Axis]
Counterparty Name [Domain]
Counterparty Name [Domain]
Allianz Real Estate
Allianz Real Estate [Member]
Allianz Real Estate [Member]
Mezzanine Loan
Mezzanine Loan [Member]
Mezzanine Loan [Member]
21 East 66th Street
East 21 Street 66 [Member]
Represents the information pertaining to 21 East 66th Street, a joint venture property of the entity.
East 400 Street 57
East 400 Street 57 [Member]
Represents information pertaining to 400 East 57th Street, a property owned by the entity.
100 Park Avenue
Park Avenue, 100 [Member]
Represents the information pertaining to 100 Park Avenue, a joint venture property of the entity.
717 Fifth Avenue
Fifth Avenue, 717 [Member]
Represents the information pertaining to 717 Fifth Avenue, a joint venture property of the entity.
800 Third Avenue
Third Avenue, 800 [Member]
Represents the information pertaining to 800 Third Avenue, a joint venture property of the entity.
1745 Broadway
Jericho Plaza
Jericho Plaza 1 and 2 [Member]
Represents the information pertaining to 1 and 2 Jericho Plaza, a joint venture property of the entity.
11 West 34th Street
West 11 Street 34 [Member]
Represents the information pertaining to 11 West 34th Street, a joint venture property of the entity.
3 Columbus Circle
Columbus Circle, 3 [Member]
Represents the information pertaining to 3 Columbus Circle, a joint venture property of the entity.
280 Park Avenue
Park Avenue, 280 [Member]
Represents the information pertaining to 280 Park Avenue, a joint venture property of the entity.
1552-1560 Broadway
Broadway 1552 to 1560 [Member]
Represents the information pertaining to 1552-1560 Broadway, a joint venture property of the entity.
724 Fifth Avenue
Fifth Avenue 724 [Member]
Represents the information pertaining to 724 Fifth Avenue, a property acquired by the entity under the joint venture.
10 East 53rd Street
East 53rd Street 10 [Member]
Represents information pertaining to 10 East 53rd Street, a joint venture property of the entity.
521 Fifth Avenue
Fifth Avenue, 521 [Member]
Represents the information pertaining to 521 Fifth Avenue, a property owned by the entity.
650 Fifth Avenue
650 Fifth Avenue [Member]
650 Fifth Avenue [Member]
121 Greene Street
Greene Street 121 [Member]
Greene Street 121 [Member]
55 West 46th Street
West 46th Street 55 [Member]
West 46th Street 55 [Member]
131-137 Spring Street
Spring Street 131 to 137 [Member]
Represents information pertaining to property located at 131-137 Spring Street, owned by the entity.
605 West 42nd Street
605 West 42nd Street [Member]
605 West 42nd Street [Member]
333 East 22nd St
333 East 22nd St [Member]
333 East 22nd St [Member]
1552 Broadway
Broadway 1552 [Member]
Represents information pertaining to 1552 Broadway, a joint venture property of the entity.
Worldwide Plaza
Worldwide Plaza [Member]
Worldwide Plaza [Member]
919 Third Avenue
Third Avenue, 919 [Member]
Represents the information pertaining to 919 Third Avenue, a property owned by the entity.
Real Estate, Type of Property [Axis]
Real Estate, Type of Property [Axis]
Real Estate, Property Type [Domain]
Real Estate [Domain]
Three Retail and Two Residential Units
Three Retail and Two Residential Units [Member]
Three Retail and Two Residential Units [Member]
Three Residential Units
Three Residential Units [Member]
Three Residential Units [Member]
General information on each joint venture
Net equity investment in VIEs in which the entity is not primary beneficiary
Variable Interest Entity Not Primary Beneficiary, Investment
Represents the amount of equity investment in variable interest entities (VIEs) in which the entity is not a primary beneficiary.
Economic Interest (as a percent)
Equity Method Investment, Economic Interest Percentage
The percentage of economic interest in the investee accounted for under the equity method of accounting.
Unaudited Approximate Square Feet (sqft)
Acquisition Price
Equity Method Investment, Aggregate Cost
Purchase price and other fair value adjustments
Purchase Price Fair Value Adjustment Gross
The impact of fair value adjustments on purchase price and it's impact on net income or loss for the period, gross.
Number of stores
Number of Stores
Number of residential units
Number Of Residential Units
Number Of Residential Units
Number of properties sold
Disposal Group, Not Discontinued Operation, Number of Properties
Disposal Group, Not Discontinued Operation, Number of Properties
Ownership percentage in disposed asset
Disposal Group Including Discontinued Operation, Ownership Percentage in Disposed Asset
Disposal Group Including Discontinued Operation, Ownership Percentage in Disposed Asset
Aggregate equity committed by partners
Investment in Joint Venture, Aggregate Equity Committed by Partner
Investment in Joint Venture, Aggregate Equity Committed by Partner
Maximum ownership percentage of partners
Investment in Joint Venture, Aggregate Maximum Ownership Percentage
Investment in Joint Venture, Aggregate Maximum Ownership Percentage
Partners' ownership percentage
Investment in Joint Venture, Partners' Ownership Percentage
Investment in Joint Venture, Partners' Ownership Percentage
Equity method investment, amount sold
Equity Method Investment, Amount Sold
Cumulative effect on retained earnings
Debt and Preferred Equity Investments
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
Statement of Comprehensive Income [Abstract]
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Change in net unrealized gain on derivative instruments, including SL Green's/SLGOP's share of joint venture net unrealized (loss) gain on derivative instruments
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax
Change in unrealized gain (loss) on marketable securities
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax
Other comprehensive income (loss)
Other Comprehensive Income (Loss), Net of Tax
Comprehensive income
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Net (income) loss attributable to noncontrolling interests and preferred units distributions
Net Income (Loss) Attributable to Noncontrolling Interest
Net (loss) income attributable to noncontrolling interests
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Redeemable
Other comprehensive (loss) income attributable to noncontrolling interests
Comprehensive income attributable to SL Green/SLGOP
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Statement of Partners' Capital [Abstract]
Preferred Units
Partner Capital Components [Axis]
Partner Capital Components [Axis]
Partner Capital Components [Domain]
Partner Capital Components [Domain]
Partners' Interest
General Partner [Member]
Increase (Decrease) in Partner's Capital
Beginning Balance
Beginning Balance (units)
Partners' Capital Account, Units
Adjusted Balance
Partners' Capital, Adjusted Balance
Net income
Profit Loss, Less Preferred Distributions
The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest, less preferred distributions during the period.
Other comprehensive income
Other Comprehensive Income (Loss), Net of Tax, Less Portion Attributable to Noncontrolling Interest
Other Comprehensive Income (Loss), Net of Tax, Less Portion Attributable to Noncontrolling Interest
Preferred distributions
Distributions Preferred Units
Distributions declared for preferred units during the period.
DRSPP proceeds
Conversion of common units (in shares)
Partners' Capital Account, Units, Sale of Units
Conversion of common units
Reallocation of noncontrolling interests in the operating partnership
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings
Contribution to consolidated joint venture interests
Contributions - proceeds from stock options exercised (in shares)
Contributions - proceeds from stock options exercised
Partners' Capital Account, Option Exercise
Cash distributions declared ($1.625 per common unit, none of which represented a return of capital for federal income tax purposes)
Partners' Capital Account, Distributions
Ending Balance
Ending Balance (units)
Mortgages and Other Loans Payable
-- None. No documentation exists for this element. --
Mortgages and other loans payable
Schedule of weighted average assumptions used to estimate the grant date fair value of options granted
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Summary of the status of stock options and changes during the period
Share-based Compensation, Stock Options, Activity [Table Text Block]
Summary of restricted stock and charges during the period
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]
Investments Schedule [Abstract]
Investment [Axis]
Investment [Axis]
Investment [Domain]
Investment [Domain]
Debt Investments in Mortgage Loans
Debt Investments in Mortgage Loans [Member]
Represents debt investments in mortgage loans on real estate.
Mortgage Loans on Real Estate [Line Items]
Movement in Mortgage Loans on Real Estate [Roll Forward]
Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at beginning of period
Mortgage Loans on Real Estate
Originations/Accretion
Mortgage Loans on Real Estate, New Mortgage Loans
Redemptions/Sales/Syndications/Amortization
Mortgage Loans on Real Estate, Amortization of Premium
Balance at end of period
Property Acquisitions
Business Combination Disclosure [Text Block]
One Madison Avenue
One Madison Avenue [Member]
Represents information pertaining to One Madison Avenue, a property owned by the entity.
762 Madison Avenue
Madison Avenue 762 [Member]
Represents information pertaining to property located at 762 Madison Avenue, owned by the entity.
100 Church Street
Church Street, 100 [Member]
Represents the information pertaining to 100 Church Street, a property owned by the entity.
400 East 58th Street
East 400 Street 58 [Member]
Represents information pertaining to 400 East 58th Street, a property owned by the entity.
Landmark Square
Landmark Square [Member]
Represents the information pertaining to Landmark Square, a property owned by the entity.
485 Lexington Avenue
Lexington Avenue, 485 [Member]
Represents the information pertaining to 485 Lexington Avenue, a property owned by the entity.
1080 Amsterdam Avenue
Amsterdam Avenue 1080 [Member]
Represents information pertaining to property located at 1080 Amsterdam, owned by the entity.
315 West 33rd Street
315 West 33rd Street [Member]
315 West 33rd Street [Member]
719 Seventh Avenue
Seven One Nine Seventh Avenue [Member]
Seven One Nine Seventh Avenue [Member]
183, 187 Broadway & 5-7 Dey Street (7)
187 Broadway and 5-7 Dey Street [Member]
187 Broadway and 5-7 Dey Street [Member]
220 East 42nd Street
East 220 Street 42 [Member]
Represents the information pertaining to 220 East 42nd Street, a property owned by the entity.
Unsecured Loan
Unsecured Debt [Member]
Mortgage loan
Mortgages [Member]
Subordinate loan
Senior Subordinated Loans [Member]
Uncommitted Master Repurchase Agreements
Uncommitted Master Repurchase Agreements [Member]
Uncommitted Master Repurchase Agreements [Member]
Uncommitted Master Repurchase Agreement 2017
Uncommitted Master Repurchase Agreement 2017 [Member]
Uncommitted Master Repurchase Agreement 2017
Uncommitted Master Repurchase Agreement 2016
Uncommitted Master Repurchase Agreement 2016 [Member]
Uncommitted Master Repurchase Agreement 2016 [Member]
Series J Preferred Units
Series J Preferred Stock [Member]
Series J Preferred Stock [Member]
Weighted Average
Weighted Average [Member]
Interest rate, fixed rate debt (as a percent)
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate
Total fixed rate debt
Secured Debt, Bearing Fixed Interest, Amount
The portion of the carrying amount of long-term secured loans outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.
Interest rate, floating rate debt (as a percent)
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate
Total floating rate debt
Secured Debt, Bearing Variable Interest, Amount
The portion of the carrying amount of long-term secured loans outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.
Total fixed rate and floating rate debt
Secured Debt and Other Loans, Payable
Represents the carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations and other loans payable.
Mortgages reclassed to liabilities related to assets held for sale
Secured Debt, Amount Transferred to Liabilities Related to Net Assets Held for Sale
Secured Debt, Amount Transferred to Liabilities Related to Net Assets Held for Sale
Total mortgages and other loans payable
Secured Debt, Gross
Secured Debt, Gross
Deferred financing costs, net of amortization
Secured Debt, Deferred Finance Costs, Net
Secured Debt, Deferred Finance Costs, Net
Total mortgages and other loans payable, net
Term (in Years)
Total fixed rate debt
Secured Debt, Bearing Fixed Interest, Mortgage Amount
Secured Debt, Bearing Fixed Interest, Mortgage Amount
Subordinate loan
Secured Debt, Bearing Fixed Interest, Subordinate Loan Amount
Secured Debt, Bearing Fixed Interest, Subordinate Loan Amount
Preferred units (as a percent)
Preferred units, liquidation preference (in dollars per unit)
Maximum facility capacity
Line of Credit Facility, Maximum Borrowing Capacity
Book value of collateral
Collateral Already Posted, Aggregate Fair Value
Number of debt instruments
Debt Instrument, Number of Instruments
Debt Instrument, Number of Instruments
Number of extension options
Debt Instrument, Number of Extension Options
Debt Instrument, Number of Extension Options
Period of extension options
Debt Instrument, Period of Extension Option
Debt Instrument, Period of Extension Option
Extension option exercised, term
Debt Instrument, Extension Option Exercised, Term
Debt Instrument, Extension Option Exercised, Term
Basis point fee (as a percent)
Line of Credit Facility, Basis Point Fee
Line of Credit Facility, Basis Point Fee
Outstanding under line of credit facility
Credit facility, interest rate (as a percent)
Threshold amount for basis point fee to be applicable (less than)
Line of Credit Facility, Threshold Amount for Basis Point Fee
Line of Credit Facility, Threshold Amount for Basis Point Fee
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Related Party Transactions
Related Party Transactions Disclosure [Text Block]
Organization and Basis of Presentation
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Major Types of Debt and Equity Securities [Axis]
Major Types of Debt and Equity Securities [Axis]
Major Types of Debt and Equity Securities [Domain]
Major Types of Debt and Equity Securities [Domain]
Equity marketable securities
Equity Securities [Member]
Commercial mortgage-backed securities
Commercial Mortgage Backed Securities [Member]
Measurement Basis [Axis]
Measurement Basis [Axis]
Fair Value Measurement [Domain]
Fair Value Measurement [Domain]
Portion at Fair Value Measurement [Member]
Portion at Fair Value Measurement [Member]
Fair Value
Estimate of Fair Value Measurement [Member]
Investment in Marketable Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities
Available-for-sale Securities
Cost basis
Available-for-sale Securities, Amortized Cost Basis
Proceeds from sale of marketable securities
Proceeds from Sale of Available-for-sale Securities
Marketable Securities, Realized Gain (Loss)
Marketable Securities, Realized Gain (Loss)
Financial Instruments: Derivatives and Hedging
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Schedule of first mortgages and other loans payable collateralized by the respective properties and assignment of leases
Mortgage and Other Loans Payable [Table Text Block]
Tabular disclosure of the information pertaining to mortgage and other loans payable of the entity. The disclosure may include but is not limited to identification of terms, features, collateral requirements and other information necessary to a fair presentation.
Schedule of components of deferred costs
Schedule of Deferred Costs [Table Text Block]
Tabular disclosure of the components of deferred costs.
Earnings Per Share
Earnings Per Share [Abstract]
Numerator
Net Income (Loss) Attributable to Parent [Abstract]
Basic Earnings:
Net Income (Loss) Available to Common Stockholders, Basic [Abstract]
Income attributable to SL Green common stockholders
Net Income (Loss) Available to Common Stockholders, Basic
Effect of Dilutive Securities:
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Redemption of units to common shares
Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities
Diluted Earnings:
Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]
Income attributable to SL Green common stockholders
Net Income (Loss) Available to Common Stockholders, Diluted
Denominator
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic Shares:
Weighted Average Number of Shares Outstanding, Basic [Abstract]
Weighted average common shares outstanding (shares)
Weighted Average Number of Shares Outstanding, Basic
Effect of Dilutive Securities:
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Operating Partnership units redeemable for common shares (shares)
Incremental Common Shares, Attributable to Redemption of Units to Common Shares
Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of the redemption of units to common shares.
Stock-based compensation plans (shares)
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Diluted weighted average common stock outstanding (shares)
Weighted Average Number of Shares Outstanding, Diluted
Common stock shares excluded from the diluted shares outstanding (shares)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
Schedule of accumulated other comprehensive income (loss)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Stockholders' Equity of the Company
Total fixed rate
Fixed Rate [Member]
Fixed Rate [Member]
Total floating rate
Debt Investment with Floating Interest Rate [Member]
Represents the debt investment in mortgage loans having a floating interest rate.
Mezzanine/Jr. Mortgage Loan with an Initial Maturity Date of April 2017
Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017 [Member]
Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017 [Member]
Mortgage Loan, February 2019
Mortgage Loan With An Initial Maturity Date Of February 2019 [Member]
Mortgage Loan With An Initial Maturity Date Of February 2019 [Member]
Mortgage Loan, August 2019
Mortgage Loan with an Initial Maturity of August 2019 [Member]
Mortgage Loan with an Initial Maturity of August 2019 [Member]
Mezzanine Loan with an Initial Maturity Date of March 2020
Mezzanine Loan with an Initial Maturity Date of March 2020 [Member]
Mezzanine Loan with an Initial Maturity Date of March 2020 [Member]
Mortgage and Mezzanine Loan with an Initial Maturity Date of April 2020 [Member]
Mortgage and Mezzanine Loan with an Initial Maturity Date of April 2020 [Member]
Mortgage and Mezzanine Loan with an Initial Maturity Date of April 2020 [Member]
Mezzanine Loan, September 2021
Mezzanine Loan with an Initial Maturity Date of September 2021 [Member]
Mezzanine Loan with an Initial Maturity Date of September 2021 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2022
Mezzanine Loan with an Initial Maturity Date of April 2022 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2022 [Member]
Mezzanine Loan, November 2023
Mezzanine Loan, with an Initial Maturity Date of November 2023 [Member]
Mezzanine Loan, with an Initial Maturity Date of November 2023 [Member]
Mezzanine Loan, with an Initial Maturity Date of June 2024
Mezzanine Loan with an Initial Maturity Date of June 2024 [Member]
Mezzanine Loan with an Initial Maturity Date of June 2024 [Member]
Mezzanine Loan, January 2025
Mezzanine Loan, with an Initial Maturity Date of January 2025 [Member]
Mezzanine Loan, with an Initial Maturity Date of January 2025 [Member]
Mezzanine Loan with an Initial Maturity Date of November 2026
Mezzanine Loan with an Initial Maturity Date of November 2026 [Member]
Mezzanine Loan with an Initial Maturity Date of November 2026
Mezzanine Loan with an Initial Maturity Date of June 2027
Mezzanine Loan with an Initial Maturity Date of June 2027 [Member]
Mezzanine Loan with an Initial Maturity Date of June 2027 [Member]
Real Estate Acquired in Satisfaction of Debt [Member]
Mortgage and Jr Mortgage loan satisfied via foreclosure [Member]
Mortgage and Jr Mortgage loan satisfied via foreclosure [Member]
Mezzanine Loan with an Initial Maturity Date of December 2017
Mezzanine Loan with an Initial Maturity Date of April 2018, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2018, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2018
Mezzanine Loan with an Initial Maturity Date of April 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of August 2018
Mezzanine Loan with an Initial Maturity Date of August 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of August 2018 [Member]
Mortgage/Mezzanine Loan, with an Initial Maturity Date of August 2018
Mortgage/Mezzanine Loan, with an Initial Maturity Date of August 2018 [Member]
Mortgage/Mezzanine Loan, with an Initial Maturity Date of August 2018 [Member]
Mezzanine Loan With An Initial Maturity Date of August 2018, 2
Mezzanine Loan With An Initial Maturity Date of August 2018, 2 [Member]
Mezzanine Loan With An Initial Maturity Date of August 2018, 2 [Member]
Mortgage/Mezzanine Loan, September 2018
Mortgage/Mezzanine Loan with an Initial Maturity Date of September 2018 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of September 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of September 2018
Mezzanine Loan with an Initial Maturity Date of September 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of September 2018 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2016 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2018 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of October 2018
Mezzanine Loan with an Initial Maturity Date of October 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of October 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018
Mezzanine Loan with an Initial Maturity Date of December 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 2
Mezzanine Loan with an Initial Maturity Date of December 2018, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 3
Mezzanine Loan with an Initial Maturity Date of December 2018, 3 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 3 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 4
Mezzanine Loan with an Initial Maturity Date of December 2018, 4 [Member]
Mezzanine Loan with an Initial Maturity Date of December 2018, 4 [Member]
Mezzanine Loan with an Initial Maturity Date of January 2019
Mezzanine Loan with an Initial Maturity Date of January 2019 [Member]
Mezzanine Loan with an Initial Maturity Date of January 2019 [Member]
Mezzanine Loan with an Initial Maturity of January 2019, 2
Mezzanine Loan with an Initial Maturity of January 2019, 3 [Member]
Mezzanine Loan with an Initial Maturity of January 2019, 3 [Member]
Mezzanine Loan with an Initial Maturity of March 2019
Mezzanine Loan with an Initial Maturity of March 2019 [Member]
Mezzanine Loan with an Initial Maturity of March 2019 [Member]
Mezzanine Loan with an Initial Maturity of March 2019, 2
Mezzanine Loan with an Initial Maturity of March 2019, 2 [Member]
Mezzanine Loan with an Initial Maturity of March 2019, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2019
Mezzanine Loan with an Initial Maturity Date of April 2019 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2019 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2019, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2019, 2 [Member]
Mezzanine Loan with an Initial Maturity Date of April 2019, 2 [Member]
Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019
Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019 [Member]
Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019 [Member]
Mezzanine Loan, Maturity of September 2019
Mezzanine Loan, Maturity of September 2019 [Member]
Mezzanine Loan, Maturity of September 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of September 2019
Mortgage/Mezzanine Loan with an Initial Maturity of September 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of September 2019 [Member]
Mezzanine Loan with an Initial Maturity of October 2019 [Member]
Mezzanine Loan with an Initial Maturity of October 2019 [Member]
Mezzanine Loan with an Initial Maturity of October 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2019 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of January 2020
Mortgage/Mezzanine Loan with an Initial Maturity of January 2020 [Member] [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of January 2020 [Member] [Member]
Mezzanine Loan with an Initial Maturity of January 2020
Mezzanine Loan with an Initial Maturity of January 2020 [Member]
Mezzanine Loan with an Initial Maturity of January 2020 [Member]
Mortgage Loan with an Initial Maturity of February 2020 [Member]
Mortgage Loan with an Initial Maturity of February 2020 [Member]
Mortgage Loan with an Initial Maturity of February 2020 [Member]
Mezzanine Loan with an Initial Maturity of July 2020 [Member]
Mezzanine Loan with an Initial Maturity of July 2020 [Member]
Mezzanine Loan with an Initial Maturity of July 2020 [Member]
Mezzanine Loan with an Initial Maturity of July 2020 [Domain]
Mezzanine Loan with an Initial Maturity of November 2020 [Member]
Mezzanine Loan with an Initial Maturity of November 2020 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020, 2 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020, 2 [Member]
Mortgage/Mezzanine Loan with an Initial Maturity of December 2020, 2 [Member]
Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021
Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021 [Member]
Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021 [Member]
Mezzanine Loan with an Initial Maturity of August 2022
Mezzanine Loan With An Initial Maturity Of August 2022 [Member]
Mezzanine Loan With An Initial Maturity Of August 2022
Mortgage/Mezzanine Loan repaid in June 2017
Mortgage/Mezzanine Loan repaid in February 2018 [Member]
Mortgage/Mezzanine Loan repaid in February 2018 [Member]
Mezzanine Loan Contributed for a Joint Venture Interest
Mezzanine Loan repaid in February 2018 [Member]
Mezzanine Loan repaid in February 2018 [Member]
Junior Mortgage Participation, Related To Mortgage Loan, February 2019
Junior Mortgage Participation, Related To Mortgage Loan, February 2019 [Member]
Junior Mortgage Participation, Related To Mortgage Loan, February 2019 [Member]
Debt Investments Held [Abstract]
Debt Investments Held [Abstract]
Debt Investments Held [Abstract]
Carrying Value
Loans and Leases Receivable, Gross
Interest Receivable
Interest Receivable
Loan acquired
Receivable with Imputed Interest, Face Amount
Discount amount
Receivable with Imputed Interest, Discount
Amount participated out
Mortgage Loans on Real Estate Loan Value
Represents the amount of loan participation on property mortgage.
Loan reserves
Provision for Loan and Lease Losses
Schedule of Business Acquisitions, by Acquisition
Schedule of Business Acquisitions, by Acquisition [Table Text Block]
Mezzanine Loan, Initial Maturity October 2022 [Member]
Mezzanine Loan, Initial Maturity October 2022 [Member]
Mezzanine Loan, Initial Maturity October 2022 [Member]
Secured Debt, Initial Maturity August 2019
Secured Debt, Initial Maturity August 2019 [Member]
Secured Debt, Initial Maturity August 2019 [Member]
Secured Debt, Initial Maturity June 2024
Secured Debt, Initial Maturity June 2024 [Member]
Secured Debt, Initial Maturity June 2024 [Member]
Secured Debt, Initial Maturity April 2028
Secured Debt, Initial Maturity April 2028 [Member]
Secured Debt, Initial Maturity April 2028 [Member]
21 East 66th Street
175-225 Third Street Brooklyn, New York
Jericho Plaza
1552 Broadway
280 Park Avenue
11 West 34th Street
Mezzanine loans
Mezzanine Loans on Real Estate [Member]
Represents the mezzanine loans on real estate properties.
Construction Loans
Construction Loans [Member]
Total joint venture mortgages and other loans payable, net
Secured Debt and Other Loans, Payable, Net
Secured Debt and Other Loans, Payable, Net
Committed amount
Debt Instrument, Committed Amount
Represents the maximum committed amount of the debt instrument.
Long-term debt, carrying value
Long-term Debt
Unused borrowing capacity, amount
Debt Instrument, Unused Borrowing Capacity, Amount
Schedule of debt and preferred equity book balance roll forward
Schedule Of Debt And Preferred Equity Book Balance Roll Forward [Table Text Block]
Schedule Of Debt And Preferred Equity Book Balance Roll Forward
Summary of debt investments
Schedule of Mortgage Loans on Real Estate [Table Text Block]
Tabular disclosure of investments in mortgage loans on real estate.
Summary of preferred equity investments
Investments Classified by Contractual Maturity Date [Table Text Block]
Series I Preferred Units
Units outstanding (units)
Period of restriction to redeem OP Units
Common Units Redemption, Period Of Restriction
Common Units Redemption, Period Of Restriction
Conversion of stock, shares issued
Conversion of Stock, Shares Issued
Noncontrolling interest in the operating partnership (as a percent)
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)
Issuance of common stock (in shares)
Stock Issued During Period, Shares, New Issues
Dividend reinvestments/stock purchases under the DRSPP
Proceeds from Issuance of Common Stock
Income Statement [Abstract]
Revenues
Revenues [Abstract]
Rental revenue, net
Operating Leases, Income Statement, Minimum Lease Revenue
Escalation and reimbursement
Tenant Reimbursements
Investment income
Investment Income, Interest and Dividend
Other income
Other Income
Total revenues
Revenues
Expenses
Costs and Expenses [Abstract]
Operating expenses, including related party expenses of $4,665 and $8,499 in 2018 and $5,262 and $9,436 in 2017, respectively.
Transaction related costs
Marketing, general and administrative
Selling, General and Administrative Expense
Net income before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, (loss) gain on sale of real estate net, depreciable real estate reserves, and gain on sale of marketable securities
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest
Equity in net income from unconsolidated joint ventures
(Loss) gain on sale of real estate, net
Gain on sale of investment in marketable securities
Marketable Securities, Gain (Loss)
Net income
Net (income) loss attributable to noncontrolling interests:
Net Income (Loss) Attributable to Noncontrolling Interest [Abstract]
Noncontrolling interests in the Operating Partnership
Noncontrolling interests in other partnerships
Preferred units distributions
Noncontrolling Interest in Net Income (Loss) Preferred Unit Holders, Redeemable
Net income (loss) attributable to SL Green/SLGOP
Net Income (Loss) Attributable to Parent
Perpetual preferred stock dividends
Perpetual preferred unit distributions
Preferred Stock Dividends and Other Adjustments
Net income attributable to SLGOP common unitholders
Net Income (Loss) Allocated to, Common Unitholders
This element represents amounts attributable to ROP common unitholders.
Amounts attributable to SL Green common stockholders:
Income Amounts Attributable to Parent, Disclosures [Abstract]
Income before depreciable real estate reserves and gains on sale and fair value adjustments
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent
Purchase price and other fair value adjustments
Purchase Price Fair Value Adjustments Attributable to Parent
The impact of fair value adjustments on purchase price and it's impact on net income or loss for the period attributable to parent.
Equity in net gain on sale of interest in unconsolidated joint venture/real estate
Gain (Loss) on Sale of Unconsolidated Joint Ventures or Real Estate
Gain (Loss) on Sale of Unconsolidated Joint Ventures or Real Estate reflects the amount by which the consideration received exceeds (is exceeded by) the net carrying amount (reflecting previous provisions for loss on disposal, if any) of the disposal group.
(Loss) gain on sale of real estate, net
Gains (Losses) on Sales of Investment Real Estate, Attributable to Parent
Gains (Losses) on Sales of Investment Real Estate, Attributable to Parent
Depreciable real estate reserves
Depreciable Real Estate Reserves, Effect on Earnings, Attributable to Parent
Depreciable Real Estate Reserves, Effect on Earnings, Attributable to Parent
Net income attributable to SL Green common stockholders
Basic earnings per share:
Earnings Per Share, Basic [Abstract]
Income (loss) before depreciable real estate reserves and gains (losses) on sale (in dollars per share)
Income (Loss) from Continuing Operations, Per Outstanding Limited Partnership Unit, Basic, Net of Tax
Income (loss) before depreciable real estate reserves and gains (losses) on sale (in dollars per share)
Income (Loss) from Continuing Operations, Per Basic Share
Purchase price and other fair value adjustments (in dollars per share)
Purchase Price Fair Value Adjustment, Per Basic Unit
Purchase Price Fair Value Adjustment, Per Basic Unit
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (in dollars per share)
Gain (Loss) on Sale of Unconsolidated Joint Ventures or Real Estate, Per Basic Share
The amount of gain (loss) from sale of unconsolidated joint ventures or real estate per basic share.
Gain on sale of real estate, net (in dollars per share)
Gains (Losses) on Sales of Investment Real Estate, Per Basic Share
Gains (Losses) on Sales of Investment Real Estate, Per Basic Share
Depreciable real estate reserves (in dollars per share)
Depreciable Real Estate Reserves, Effect on Earnings, Per Basic Share
Depreciable Real Estate Reserves, Effect on Earnings, Per Basic Share
Net income attributable to SL Green common stockholders (usd per share)
Earnings Per Share, Basic
Net income attributable to SLGOP common unitholders (usd per share)
Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax
Diluted earnings per share:
Earnings Per Share, Diluted [Abstract]
Income (loss) before depreciable real estate reserves and gains (losses) on sale (in dollars per share)
Income (Loss) from Continuing Operations, Net of Tax, Per Outstanding Limited Partnership Unit, Diluted
Purchase price and other fair value adjustments (in dollars per share)
Purchase Price Fair Value Adjustment, Per Diluted Unit
Purchase Price Fair Value Adjustment, Per Diluted Unit
Income (loss) before depreciable real estate reserves and gains (losses) on sale (in dollars per share)
Income (Loss) from Continuing Operations, Per Diluted Share
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (in dollars per share)
Gain (Loss) on Sale of Unconsolidated Joint Ventures or Real Estate, Per Diluted Share
The amount of gain (loss) from sale of unconsolidated joint ventures or real estate per diluted share.
Gain on sale of real estate (in dollars per share)
Gains (Losses) on Sales of Investment Real Estate, Per Diluted Share
Gains (Losses) on Sales of Investment Real Estate, Per Diluted Share
Depreciable real estate reserves (in dollars per share)
Depreciable Real Estate Reserves, Effect on Earnings, Per Diluted Share
Depreciable Real Estate Reserves, Effect on Earnings, Per Diluted Share
Net income attributable to SL Green common stockholders (usd per share)
Earnings Per Share, Diluted
Net income attributable to SLGOP common unitholders (usd per share)
Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted
Dividends per share/unit (usd per share)
Basic weighted average common shares outstanding (in shares)
Basic weighted average common units outstanding (in shares)
Weighted Average Limited Partnership Units Outstanding, Basic
Diluted weighted average common shares and common share equivalents outstanding (in shares)
Diluted weighted average common units and common unit equivalents outstanding (in shares)
Weighted Average Limited Partnership Units Outstanding, Diluted
Summary of properties sold
Disposal Groups, Including Discontinued Operations [Table Text Block]
Variable Interest Entities [Axis]
Variable Interest Entities [Axis]
Variable Interest Entity, Classification [Domain]
Variable Interest Entity, Classification [Domain]
Consolidated VIEs
Variable Interest Entity, Primary Beneficiary [Member]
Tenant and other receivables, allowance
Allowance for Doubtful Accounts, Premiums and Other Receivables
Deferred rents receivable, allowance
Allowance for Deferred Rents Receivable
The valuation allowances attributable to, for instance, credit risk associated with a lessee as of the balance sheet date to reduce the gross amount of deferred rents receivable, which would be presented in parentheses on the face of the balance sheet.
Debt and preferred equity investments, discount and deferred origination fees
Discount of Structured Finance Investments
This item represents the net amount of discounts related to investments in structured finance investments.
Preferred stock, liquidation preference (in dollars per share)
Preferred stock, shares issued (in shares)
Preferred Stock, Shares Issued
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)
Limited Partners' Capital Account, Units Outstanding
Preferred units, liquidation preference (in dollars per share)
Preferred units, shares issued (in shares)
Preferred units, shares outstanding (in shares)
Temporary Equity, Shares Outstanding
Common stock, shares issued (in shares)
Common Stock, Shares, Issued
Common stock, shares outstanding (in shares)
Common Stock, Shares, Outstanding
Treasury stock, shares (in shares)
Treasury Stock, Shares
SL Green partner's capital, general partner common units outstanding (shares)
General Partners' Capital Account, Units Outstanding
SL Green partners' capital, limited partner common units outstanding (shares)
Limited Partnership Units Held by General Partner
This element represents Limited Partnership Units Held by General Partner.
Accumulated depreciation
Schedule of Preferred Units [Table]
Schedule of Preferred Units [Table]
Preferred Units [Line Items]
Preferred Units [Line Items]
Rollforward Analysis of Preferred Unit Activity
Rollforward Analysis of Preferred Unit Activity [Roll Forward]
Rollforward Analysis of Preferred Unit Activity [Roll Forward]
Balance at beginning of period
Noncontrolling Interest in Preferred Unit Holders
Issuance of preferred units
Redemption of preferred units
Balance at end of period
Net income attributable to SLGOP common unitholders
Stock-based compensation plans (shares)
Incremental Common Units Attributable to Share based Payment Arrangements
Incremental Common Units Attributable to Share based Payment Arrangements
Diluted weighted average common units outstanding (shares)
Weighted Average Number of Units Outstanding Diluted
Weighted Average Number of Units Outstanding Diluted
Segment Information
Segment Reporting Disclosure [Text Block]
Fair Value Disclosures [Abstract]
Fair Value, Hierarchy [Axis]
Fair Value, Hierarchy [Axis]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Fair Value Hierarchy [Domain]
Level 1
Fair Value, Inputs, Level 1 [Member]
Level 2
Fair Value, Inputs, Level 2 [Member]
Level 3
Fair Value, Inputs, Level 3 [Member]
Carrying Value
Reported Value Measurement [Member]
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)
Derivative Asset, Fair Value, Gross Asset
Notes receivable
Mortgage Loans on Real Estate, Face Amount of Mortgages
Accrued interest
Debt and preferred equity investments
Fixed rate debt
Long-term Debt, Percentage Bearing Fixed Interest, Amount
Variable rate debt
Long-term Debt, Percentage Bearing Variable Interest, Amount
Total
Long-term Debt, Fair Value
Additional amount of financing receivables included in other assets
Financing Receivable, Recorded in Other Assets
Represents the amount of financing receivables recorded in other assets on the entity's balance sheet.
Estimated fair value of debt and preferred equity investments, low end of range
Mortgage Loans on Real Estate, Fair Value, Low End of Range
Represents the low end of the range of estimated fair value for investments in mortgage loans on real estate.
Estimated fair value of debt and preferred equity investments, high end of range
Mortgage Loans on Real Estate Fair Value, High End of Range
Represents the high end of the range of estimated fair value for investments in mortgage loans on real estate.
Interest expense
Interest Income (Expense), Net [Abstract]
Interest expense before capitalized interest
Interest Expense
Interest capitalized
Capitalized Interest Costs, Including Allowance for Funds Used During Construction
Interest income
Interest Income, Operating
Interest expense, net
Interest Income (Expense), Net
Schedule of Segment Reporting Information, by Segment [Table]
Schedule of Segment Reporting Information, by Segment [Table]
Consolidation Items [Axis]
Consolidation Items [Axis]
Consolidation Items [Domain]
Consolidation Items [Domain]
Operating Segments
Operating Segments [Member]
Business Segments [Axis]
Segments [Axis]
Segment [Domain]
Segments [Domain]
Real Estate Segment
Real Estate Segment [Member]
Represents the information pertaining to the reportable segment of the entity, Real Estate Segment.
Debt and Preferred Equity Segment
Structured Finance Segment [Member]
Represents the information pertaining to the reportable segment of the entity, Structured Finance Segment.
Segment information
Segment Reporting Information [Line Items]
Number of reportable segments (segment)
Number of Reportable Segments
Total revenues
Net income (loss) before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, (loss) gain on sale of real estate net, depreciable real estate reserves, and gain on sale of marketable securities
Income (Loss) from Continuing Operations before Realized Gain (Loss) on Disposal of Equity Method Investment
This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before realized gains (losses) on disposals of equity method investments, extraordinary items, and noncontrolling interest.
Total assets
Deferred leasing costs
Deferred Costs, Leasing, Gross
Less: accumulated amortization
Accumulated Amortization of Deferred Costs
The accumulated amortization, as of the reporting date, representing the periodic charge to earnings of deferred costs.
Deferred costs, net
Operating expenses, paid to related parties
Affiliate Costs
Principles of Consolidation
Consolidation, Policy [Policy Text Block]
Investment in Commercial Real Estate Properties
Investment in Real Estate [Policy Text Block]
Disclosure of accounting policy for investments in real estate properties.
Fair Value Measurements
Fair Value of Financial Instruments, Policy [Policy Text Block]
Investment in Marketable Securities
Marketable Securities, Policy [Policy Text Block]
Investments in Unconsolidated Joint Ventures
Equity Method Investments [Policy Text Block]
Reserve for Possible Credit Losses
Financing Receivable, Allowance for Credit Losses, Policy or Methodology Change [Policy Text Block]
Income Taxes
Income Tax, Policy [Policy Text Block]
Use of Estimates
Use of Estimates, Policy [Policy Text Block]
Concentrations of Credit Risk
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Reclassification
Reclassification, Policy [Policy Text Block]
Accounting Standards Updates
New Accounting Pronouncements, Policy [Policy Text Block]
Disposal Group Classification [Axis]
Disposal Group Classification [Axis]
Disposal Group Classification [Domain]
Disposal Group Classification [Domain]
Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operations, Disposed of by Sale [Member]
Schedule of general information on joint ventures
Equity Method Investments [Table Text Block]
Schedule of first mortgage notes payable collateralized by the respective joint venture properties and assignment of leases
Schedule of Mortgage and Other Loans Payable on Joint Venture Properties [Table Text Block]
Tabular disclosure of the information pertaining to mortgage and other loans payable on joint venture properties of the entity.
Schedule of combined balance sheets for the unconsolidated joint ventures
Equity Method Investments, Summarized Financial Information Balance Sheet [Table Text Block]
Disclosure of summarized balance sheet financial information for investments accounted for using the equity method of accounting.
Schedule of combined statements of income for the unconsolidated joint ventures
Equity Method Investments, Summarized Financial Information Income Statement [Table Text Block]
Disclosure of summarized income statement information for investments accounted for using the equity method of accounting.
Junior Mortgage Participation Acquired in September 2014
Junior Mortgage Participation Acquired in September 2014 [Member]
Junior Mortgage Participation Acquired in September 2014 [Member]
Receivable with Imputed Interest, Face Amount
Payments to acquire loans
Payments to Acquire Loans Receivable
Number of portfolio segments of financial receivables (segment)
Financing Receivable, Portfolio Segments Number
Represents the number of portfolio segments of financing receivables.
Schedule of Real Estate Properties [Table]
Schedule of Real Estate Properties [Table]
Manhattan
Manhattan [Member]
Represents information pertaining to properties located in Manhattan.
Suburban
Suburban [Member]
Represents information pertaining to property located in Suburban areas.
Real Estate Property Ownership [Axis]
Real Estate Property Ownership [Axis]
Real Estate Properties [Domain]
Real Estate Properties [Domain]
Consolidated properties
Consolidated Properties [Member]
Unconsolidated properties
Unconsolidated Properties [Member]
Office
Office Properties [Member]
Represents the investment in office properties owned by the entity.
Retail
Retail Properties [Member]
Represents information pertaining to retail properties owned by the entity.
Development/Redevelopment
Development Properties [Member]
Represents the development properties owned by the entity.
Fee Interest
Fee Interest [Member]
Fee Interest [Member]
Commercial properties
Commercial Property [Member]
Commercial Property [Member]
Residential
Residential Real Estate [Member]
Dual property type, retail portion
Dual Property Type, Retail Portion [Member]
Dual Property Type, Retail Portion [Member]
Dual property type, residential portion
Dual Property Type, Residential Portion [Member]
Dual Property Type, Residential Portion [Member]
Managed office properties
Managed Office Properties [Member]
Represents the office properties managed by the entity.
Real estate properties
Real Estate Properties [Line Items]
Number of Properties
Number of Real Estate Buildings
Number of Real Estate Buildings
Approximate Square Feet unaudited (sqft)
Weighted Average Occupancy unaudited (as a percent)
Real Estate Weighted Average Occupancy
Represents the weighted average occupancy of real estate properties owned, which represents the total leased square feet divided by the total available rentable square feet.
Debt and preferred equity investments including investments held by unconsolidated joint ventures
Mortgage Loans on Real Estate, Commercial and Consumer, Net Including Debt Investments, Other
Mortgage Loans on Real Estate, Commercial and Consumer, Net Including Debt Investments, Other
Debt and preferred equity investments and other financing receivables included in other balance sheet items
Debt Investments, Other
Debt Investments, Other
Number of shares to be received on redemption of one unit of limited partnership interests (shares)
Number of Shares on Redemption of One Unit of Partnership Interest
Represents the number of shares of the common stock of the entity, which the limited partner of the operating partnership is entitled to receive on redemption of one unit of interest in the partnership.
Derivative [Table]
Derivative [Table]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract Type [Domain]
Derivative Contract [Domain]
Interest Rate Swap Expiring in July 2023
Interest Rate Swap Expiring in July 2023 [Member]
Interest Rate Swap Expiring in July 2023 [Member]
Interest Rate Swap Expiring in July 2023
Interest Rate Swap Expiring in July 2023, 2 [Member]
Interest Rate Swap Expiring in July 2023, 2 [Member]
Interest Rate Cap Expiring September 2019
Interest Rate Cap Expiring September 2019 [Member]
Interest Rate Cap Expiring September 2019 [Member]
Interest Rate Swap Expiring November 2020
Interest Rate Swap Expiring November 2020 [Member]
Interest Rate Swap Expiring November 2020 [Member]
Interest Rate Swap Expiring November 2020, 2
Interest Rate Swap Expiring November 2020, 2 [Member]
Interest Rate Swap Expiring November 2020, 2 [Member]
Interest Rate Swaps/Caps
Interest Rate Swap [Member]
Financial Instruments: Derivatives and Hedging
Derivative [Line Items]
Notional Value
Derivative Asset, Notional Amount
Strike Rate
Derivative, Fixed Interest Rate
Fair Value
Derivative, Fair Value, Net
Gain (loss) from changes in fair value
Accumulated Other Comprehensive Income (Loss), Gain (Loss) from Changes in Fair Value
Accumulated Other Comprehensive Income (Loss), Gain (Loss) from Changes in Fair Value
Fair value of derivatives in a net liability position
Derivative, Net Liability Position, Aggregate Fair Value
Aggregate termination value
Assets Needed for Immediate Settlement, Aggregate Fair Value
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months into Equity in Net Income
Represents the estimated net amount of existing gains (losses) on cash flow hedges at the reporting date expected to be reclassified to equity in net income within the next 12 months.
Amount of Gain (Loss) Recognized in Other Comprehensive Loss (Effective Portion)
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net
Amount of Gain (Loss) Recognized into Income (Ineffective Portion)
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness
Fair Value Measurements
Fair Value Disclosures [Text Block]
Fair value measurements, recurring and nonrecurring
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]
Fair value, by balance sheet grouping
Fair Value, by Balance Sheet Grouping [Table Text Block]
Plan Name [Axis]
Plan Name [Axis]
Plan Name [Domain]
Plan Name [Domain]
Third Amendment and Restated 2005 Stock Option and Incentive Plan
Third Amendment and Restated 2005 Stock Option and Incentive Plan [Member]
Third Amendment and Restated 2005 Stock Option and Incentive Plan [Member]
Stock options, stock appreciation rights and other awards
Stock Options Stock Appreciation Rights and Other Awards [Member]
Represents the stock options, stock appreciation rights and other awards granted by the entity. Thes do not deliver full value and have an expiration date.
All other awards
Other Awards [Member]
Represents awards granted by the entity that deliver the full value of the award upon vesting.
2014 Outperformance Plan
Long Term Outperformance Compensation Program 2014 [Member]
Long Term Outperformance Compensation Program 2014 [Member]
Deferred Stock Compensation Plan for Directors
Deferred Stock Compensation Plan for Directors [Member]
Represents the Deferred Stock Compensation Plan for Directors of the entity.
Employee Stock Purchase Plan
Employee Stock Purchase Plan [Member]
Employee Stock Purchase Plan [Member]
Class O LTIP Units
Class O LTIP Units [Member]
Class O LTIP Units [Member]
LTIP units
Long Term Incentive Plan Units [Member]
LTIP units as awarded by a company to its employees as a form of incentive compensation.
Performance Shares
Performance Shares [Member]
Vesting [Axis]
Vesting [Axis]
Vesting [Domain]
Vesting [Domain]
Vesting on August 31, 2017
Share-based Compensation Award, Tranche Three [Member]
Vesting on August 31, 2018
Share-based Compensation Award, Tranche Four [Member]
Share-based Compensation Award, Tranche Four [Member]
Maximum fungible units that may be granted (in shares)
Share Based Compensation Arrangement by Share Based Payment Award, Number of Fungible Units Authorized
Represents the maximum number of fungible units authorized to be granted by the entity.
Fungible units per share (in fungible units per share)
Share Based Compensation Arrangement by Share Based Payment Award, Fungible Units Per Share
Share Based Compensation Arrangement by Share Based Payment Award, Fungible Units Per Share
Award expiration period (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period
Shares that may be issued if equal to fungible units (shares) (less than)
Share Based Compensation Arrangement by Share Based Payment Award, Number of Shares to be Issued if Equal to Fungible Units
Represents the number of shares that would be issued under the plan if shares issued is equal to fungible units; actual shares issued may be more or less depending on the type of awards issued and the ratio of fungible units to shares under each award.
Fungible units
Share-based Compensation Arrangement By Share-based Payment Award, Number Of Fungible Units Available For Grant
Share-based Compensation Arrangement By Share-based Payment Award, Number Of Fungible Units Available For Grant
Options vesting period (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period
Period of commencement of option vesting, from date of grant (in years)
Share Based Compensation Arrangement by Share Based Payment Award, Period of Award Vesting Commencement
Represents the period from the date of grant of the awards for the commencement of vesting of awards.
Exercise price of options granted, low end of the range (in dollars per share)
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit
Exercise price of options granted, high end of the range (in dollars per share)
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit
Remaining weighted average contractual life of the options outstanding (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
Remaining average contractual life of the options exercisable (in years)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term
Compensation expense
Allocated Share-based Compensation Expense
Total unrecognized compensation cost related to unvested stock awards
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized
Weighted average period for recognition of compensation cost related to unvested stock awards (in years)
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition
Annual award vesting rate, low end of range (as a percent)
Share Based Compensation Arrangement by Share Based Payment Award, Award Vesting Rate, Low End of Range
Represents the low end of the range of annual vesting rates that occurs once performance criteria are reached.
Annual award vesting rate, high end of range (as a percent)
Share Based Compensation Arrangement by Share Based Payment Award, Award Vesting Rate, High End of Range
Represents the low end of the range of annual vesting rates that occurs once performance criteria are reached.
Fair value of restricted stock vested during the period
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value
Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount
Weighted average fair value of options granted during the period
Share-based compensation
Share-based Compensation
LTIP units earned (in shares)
Share Based Compensation, Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Awards Earned
Represents the awards earned by all participants under the stock based compensation plans.
Award period (in years)
Share-based Compensation Arrangement by Share--based Payment Award, Stock Appreciation Period
Share-based Compensation Arrangement by Share--based Payment Award, Stock Appreciation Period
Maximum award to be earned, if performance reaches maximum threshold, first performance period
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Award To Be Earned, If Performance Reaches Maximum Threshold, First Performance Period
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Award To Be Earned, If Performance Reaches Maximum Threshold, First Performance Period
Maximum award to be earned, if performance reaches maximum threshold, second performance period
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Award To Be Earned, If Performance Reaches Maximum Threshold, Second Performance Period
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Award To Be Earned, If Performance Reaches Maximum Threshold, Second Performance Period
Percentage of units vested
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage
Maximum percentage of the annual retainer fee, chairman fees and meeting fees that may be deferred by non-employee directors (percent)
Deferred Compensation Arrangement with Individual Maximum Percentage of the Compensation that May be Deferred
Represents the maximum percentage of the compensation that may be deferred by employees of the entity under deferred compensation plans.
Awards granted (in shares)
Shares issued (in shares)
Deferred Compensation Arrangement with Individual, Shares Issued
Awards outstanding (in shares)
Duration of each offering period starting the first day of each calendar quarter (in months)
Share Based Compensation Arrangement by Share Based Payment Award, Duration of Offering Periods
Represents the duration of each offering period during which the shares are offered for purchase under the stock-based compensation plan of the entity.
Discount from market price
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date
Shares of common stock issued (shares)
Common Stock, Shares Held in Employee Trust, Shares
Share Based Compensation Arrangement by Share Based Payment Award, Preferred Unit Distributions as a Percentage of Common Unit Distributions
Share Based Compensation Arrangement by Share Based Payment Award, Preferred Unit Distributions as a Percentage of Common Unit Distributions
Share Based Compensation Arrangement by Share Based Payment Award, Preferred Unit Distributions as a Percentage of Common Unit Distributions
Initial term of non cancellable operating leases, minimum (in years)
Operating Leases, Minimum Lease Term
Represents the initial minimum term of the non cancellable operating leases.
Capital lease
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Fiscal Year Maturity [Abstract]
Remaining 2018
Capital Leases, Future Minimum Payments, Remainder of Fiscal Year
2019
Capital Leases, Future Minimum Payments Due, Next Twelve Months
2020
Capital Leases, Future Minimum Payments Due in Two Years
2021
Capital Leases, Future Minimum Payments Due in Three Years
2022
Capital Leases, Future Minimum Payments Due in Four Years
2023
Capital Leases, Future Minimum Payments Due in Five Years
Thereafter
Capital Leases, Future Minimum Payments Due Thereafter
Total minimum lease payments
Capital Leases, Future Minimum Payments Due
Amount representing interest
Capital Leases, Future Minimum Payments, Interest Included in Payments
Amount classified within liabilities held for sale
Capital Leases, Held For Sale
Capital Leases, Held For Sale
Capital lease obligations
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments
Non-cancellable operating leases
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remaining 2018
Operating Leases, Future Minimum Payments, Remainder of Fiscal Year
2019
Operating Leases, Future Minimum Payments Due, Next Twelve Months
2020
Operating Leases, Future Minimum Payments, Due in Two Years
2021
Operating Leases, Future Minimum Payments, Due in Three Years
2022
Operating Leases, Future Minimum Payments, Due in Four Years
2023
Operating Leases, Future Minimum Payments, Due in Five Years
Thereafter
Operating Leases, Future Minimum Payments, Due Thereafter
Total minimum lease payments
Operating Leases, Future Minimum Payments Due
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Revolving credit facility
Revolving Credit Facility [Member]
Term Loan B, Maturity November 21, 2024
Term Loan B, Maturity November 21, 2024 [Member]
Term Loan B [Member]
Revolving Credit Facility, Maturity March 31, 2022
Revolving Credit Facility, Maturity March 31, 2022 [Member]
Revolving Credit Facility, Maturity March 31, 2022 [Member]
Term loan
2012 Credit Facility
Term Loan A, Maturity March 31, 2023
Term Loan A, Maturity March 31, 2023 [Member]
Term Loan A [Member]
Line of Credit
Line of Credit [Member]
Corporate Indebtedness
Credit facility, maximum borrowing capacity
Number of extensions
Line Of Credit Facility, Number Of Extensions
Line Of Credit Facility, Number Of Extensions
Term of extension
Line Of Credit Facility, Term Of Extension
Line Of Credit Facility, Term Of Extension
Maximum borrowing capacity, optional expansion
Line of Credit Facility, Optional Expansion, Maximum Borrowing Capacity
The expanded maximum borrowing capacity available, which is subject to agreement with the entity.
Facility fee (as a percent)
Line of Credit Facility, Commitment Fee Percentage
Letters of credit
Letters of Credit Outstanding, Amount
Ability to borrow under line of credit facility
Line of Credit Facility, Remaining Borrowing Capacity
Reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Net income (loss) before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, (loss) gain on sale of real estate net, depreciable real estate reserves, and gain on sale of marketable securities
Investments in Unconsolidated Joint Ventures
Equity Method Investments and Joint Ventures Disclosure [Text Block]
Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)
Schedule of Intangible Assets and Liabilities [Table Text Block]
Tabular disclosure of the aggregate amount of intangible assets and liabilities.
Schedule of marketable securities
Available-for-sale Securities [Table Text Block]