3.24.0.1 html 764 697 1 true 305 0 false 20 false false R1.htm 0000001 - Document - Cover Page Sheet http://www.slgreen.com/role/CoverPage Cover Page Cover 1 false false R2.htm 0000002 - Document - Audit Information Sheet http://www.slgreen.com/role/AuditInformation Audit Information Cover 2 false false R3.htm 0000003 - Statement - Consolidated Balance Sheets Sheet http://www.slgreen.com/role/ConsolidatedBalanceSheets Consolidated Balance Sheets Statements 3 false false R4.htm 0000004 - Statement - Consolidated Balance Sheets (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedBalanceSheetsParenthetical Consolidated Balance Sheets (Parenthetical) Statements 4 false false R5.htm 0000005 - Statement - Consolidated Statements of Operations Sheet http://www.slgreen.com/role/ConsolidatedStatementsofOperations Consolidated Statements of Operations Statements 5 false false R6.htm 0000006 - Statement - Consolidated Statements of Operations (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofOperationsParenthetical Consolidated Statements of Operations (Parenthetical) Statements 6 false false R7.htm 0000007 - Statement - Consolidated Statements of Comprehensive (Loss) Income Sheet http://www.slgreen.com/role/ConsolidatedStatementsofComprehensiveLossIncome Consolidated Statements of Comprehensive (Loss) Income Statements 7 false false R8.htm 0000008 - Statement - Consolidated Statements of Equity Sheet http://www.slgreen.com/role/ConsolidatedStatementsofEquity Consolidated Statements of Equity Statements 8 false false R9.htm 0000009 - Statement - Consolidated Statements of Equity (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofEquityParenthetical Consolidated Statements of Equity (Parenthetical) Statements 9 false false R10.htm 0000010 - Statement - Consolidated Statements of Cash Flows Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCashFlows Consolidated Statements of Cash Flows Statements 10 false false R11.htm 0000011 - Statement - Consolidated Statements of Cash Flows (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCashFlowsParenthetical Consolidated Statements of Cash Flows (Parenthetical) Statements 11 false false R12.htm 0000012 - Statement - Consolidated Balance Sheets (Partnership) Sheet http://www.slgreen.com/role/ConsolidatedBalanceSheetsPartnership Consolidated Balance Sheets (Partnership) Statements 12 false false R13.htm 0000013 - Statement - Consolidated Balance Sheets (Partnership) (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedBalanceSheetsPartnershipParenthetical Consolidated Balance Sheets (Partnership) (Parenthetical) Statements 13 false false R14.htm 0000014 - Statement - Consolidated Statements of Operations (Partnership) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofOperationsPartnership Consolidated Statements of Operations (Partnership) Statements 14 false false R15.htm 0000015 - Statement - Consolidated Statements of Operations (Partnership) (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofOperationsPartnershipParenthetical Consolidated Statements of Operations (Partnership) (Parenthetical) Statements 15 false false R16.htm 0000016 - Statement - Consolidated Statements of Comprehensive (Loss) Income (Partnership) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofComprehensiveLossIncomePartnership Consolidated Statements of Comprehensive (Loss) Income (Partnership) Statements 16 false false R17.htm 0000017 - Statement - Consolidated Statements of Capital Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCapital Consolidated Statements of Capital Statements 17 false false R18.htm 0000018 - Statement - Consolidated Statements of Capital (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCapitalParenthetical Consolidated Statements of Capital (Parenthetical) Statements 18 false false R19.htm 0000019 - Statement - Consolidated Statements of Cash Flows (Partnership) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCashFlowsPartnership Consolidated Statements of Cash Flows (Partnership) Statements 19 false false R20.htm 0000020 - Statement - Consolidated Statements of Cash Flows (Partnership) (Parenthetical) Sheet http://www.slgreen.com/role/ConsolidatedStatementsofCashFlowsPartnershipParenthetical Consolidated Statements of Cash Flows (Partnership) (Parenthetical) Statements 20 false false R21.htm 0000021 - Disclosure - Organization and Basis of Presentation Sheet http://www.slgreen.com/role/OrganizationandBasisofPresentation Organization and Basis of Presentation Notes 21 false false R22.htm 0000022 - Disclosure - Significant Accounting Policies Sheet http://www.slgreen.com/role/SignificantAccountingPolicies Significant Accounting Policies Notes 22 false false R23.htm 0000023 - Disclosure - Property Acquisitions Sheet http://www.slgreen.com/role/PropertyAcquisitions Property Acquisitions Notes 23 false false R24.htm 0000024 - Disclosure - Properties Held for Sale and Property Dispositions Sheet http://www.slgreen.com/role/PropertiesHeldforSaleandPropertyDispositions Properties Held for Sale and Property Dispositions Notes 24 false false R25.htm 0000025 - Disclosure - Debt and Preferred Equity Investments Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestments Debt and Preferred Equity Investments Notes 25 false false R26.htm 0000026 - Disclosure - Investments in Unconsolidated Joint Ventures Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVentures Investments in Unconsolidated Joint Ventures Notes 26 false false R27.htm 0000027 - Disclosure - Deferred Costs Sheet http://www.slgreen.com/role/DeferredCosts Deferred Costs Notes 27 false false R28.htm 0000028 - Disclosure - Mortgages and Other Loans Payable Sheet http://www.slgreen.com/role/MortgagesandOtherLoansPayable Mortgages and Other Loans Payable Notes 28 false false R29.htm 0000029 - Disclosure - Corporate Indebtedness Sheet http://www.slgreen.com/role/CorporateIndebtedness Corporate Indebtedness Notes 29 false false R30.htm 0000030 - Disclosure - Related Party Transactions Sheet http://www.slgreen.com/role/RelatedPartyTransactions Related Party Transactions Notes 30 false false R31.htm 0000031 - Disclosure - Noncontrolling Interests on the Company's Consolidated Financial Statements Sheet http://www.slgreen.com/role/NoncontrollingInterestsontheCompanysConsolidatedFinancialStatements Noncontrolling Interests on the Company's Consolidated Financial Statements Notes 31 false false R32.htm 0000032 - Disclosure - Stockholders' Equity of the Company Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompany Stockholders' Equity of the Company Notes 32 false false R33.htm 0000033 - Disclosure - Partners' Capital of the Operating Partnership Sheet http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnership Partners' Capital of the Operating Partnership Notes 33 false false R34.htm 0000034 - Disclosure - Share-based Compensation Sheet http://www.slgreen.com/role/SharebasedCompensation Share-based Compensation Notes 34 false false R35.htm 0000035 - Disclosure - Accumulated Other Comprehensive Income Sheet http://www.slgreen.com/role/AccumulatedOtherComprehensiveIncome Accumulated Other Comprehensive Income Notes 35 false false R36.htm 0000036 - Disclosure - Fair Value Measurements Sheet http://www.slgreen.com/role/FairValueMeasurements Fair Value Measurements Notes 36 false false R37.htm 0000037 - Disclosure - Financial Instruments: Derivatives and Hedging Sheet http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedging Financial Instruments: Derivatives and Hedging Notes 37 false false R38.htm 0000038 - Disclosure - Lease Income Sheet http://www.slgreen.com/role/LeaseIncome Lease Income Notes 38 false false R39.htm 0000039 - Disclosure - Benefit Plans Sheet http://www.slgreen.com/role/BenefitPlans Benefit Plans Notes 39 false false R40.htm 0000040 - Disclosure - Commitments and Contingencies Sheet http://www.slgreen.com/role/CommitmentsandContingencies Commitments and Contingencies Notes 40 false false R41.htm 0000041 - Disclosure - Segment Information Sheet http://www.slgreen.com/role/SegmentInformation Segment Information Notes 41 false false R42.htm 0000042 - Disclosure - Schedule III - Real Estate and Accumulated Depreciation Sheet http://www.slgreen.com/role/ScheduleIIIRealEstateandAccumulatedDepreciation Schedule III - Real Estate and Accumulated Depreciation Notes 42 false false R43.htm 9954471 - Disclosure - Significant Accounting Policies (Policies) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesPolicies Significant Accounting Policies (Policies) Policies http://www.slgreen.com/role/SignificantAccountingPolicies 43 false false R44.htm 9954472 - Disclosure - Organization and Basis of Presentation (Tables) Sheet http://www.slgreen.com/role/OrganizationandBasisofPresentationTables Organization and Basis of Presentation (Tables) Tables http://www.slgreen.com/role/OrganizationandBasisofPresentation 44 false false R45.htm 9954473 - Disclosure - Significant Accounting Policies (Tables) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesTables Significant Accounting Policies (Tables) Tables http://www.slgreen.com/role/SignificantAccountingPolicies 45 false false R46.htm 9954474 - Disclosure - Property Acquisitions (Tables) Sheet http://www.slgreen.com/role/PropertyAcquisitionsTables Property Acquisitions (Tables) Tables http://www.slgreen.com/role/PropertyAcquisitions 46 false false R47.htm 9954475 - Disclosure - Properties Held for Sale and Property Dispositions (Tables) Sheet http://www.slgreen.com/role/PropertiesHeldforSaleandPropertyDispositionsTables Properties Held for Sale and Property Dispositions (Tables) Tables http://www.slgreen.com/role/PropertiesHeldforSaleandPropertyDispositions 47 false false R48.htm 9954476 - Disclosure - Debt and Preferred Equity Investments (Tables) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsTables Debt and Preferred Equity Investments (Tables) Tables http://www.slgreen.com/role/DebtandPreferredEquityInvestments 48 false false R49.htm 9954477 - Disclosure - Investments in Unconsolidated Joint Ventures (Tables) Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesTables Investments in Unconsolidated Joint Ventures (Tables) Tables http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVentures 49 false false R50.htm 9954478 - Disclosure - Deferred Costs (Tables) Sheet http://www.slgreen.com/role/DeferredCostsTables Deferred Costs (Tables) Tables http://www.slgreen.com/role/DeferredCosts 50 false false R51.htm 9954479 - Disclosure - Mortgages and Other Loans Payable (Tables) Sheet http://www.slgreen.com/role/MortgagesandOtherLoansPayableTables Mortgages and Other Loans Payable (Tables) Tables http://www.slgreen.com/role/MortgagesandOtherLoansPayable 51 false false R52.htm 9954480 - Disclosure - Corporate Indebtedness (Tables) Sheet http://www.slgreen.com/role/CorporateIndebtednessTables Corporate Indebtedness (Tables) Tables http://www.slgreen.com/role/CorporateIndebtedness 52 false false R53.htm 9954481 - Disclosure - Related Party Transactions (Tables) Sheet http://www.slgreen.com/role/RelatedPartyTransactionsTables Related Party Transactions (Tables) Tables http://www.slgreen.com/role/RelatedPartyTransactions 53 false false R54.htm 9954482 - Disclosure - Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables) Sheet http://www.slgreen.com/role/NoncontrollingInterestsontheCompanysConsolidatedFinancialStatementsTables Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables) Tables http://www.slgreen.com/role/NoncontrollingInterestsontheCompanysConsolidatedFinancialStatements 54 false false R55.htm 9954483 - Disclosure - Stockholders' Equity of the Company (Tables) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyTables Stockholders' Equity of the Company (Tables) Tables http://www.slgreen.com/role/StockholdersEquityoftheCompany 55 false false R56.htm 9954484 - Disclosure - Partners' Capital of the Operating Partnership (Tables) Sheet http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnershipTables Partners' Capital of the Operating Partnership (Tables) Tables http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnership 56 false false R57.htm 9954485 - Disclosure - Share-based Compensation (Tables) Sheet http://www.slgreen.com/role/SharebasedCompensationTables Share-based Compensation (Tables) Tables http://www.slgreen.com/role/SharebasedCompensation 57 false false R58.htm 9954486 - Disclosure - Accumulated Other Comprehensive Income (Tables) Sheet http://www.slgreen.com/role/AccumulatedOtherComprehensiveIncomeTables Accumulated Other Comprehensive Income (Tables) Tables http://www.slgreen.com/role/AccumulatedOtherComprehensiveIncome 58 false false R59.htm 9954487 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.slgreen.com/role/FairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.slgreen.com/role/FairValueMeasurements 59 false false R60.htm 9954488 - Disclosure - Financial Instruments: Derivatives and Hedging (Tables) Sheet http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedgingTables Financial Instruments: Derivatives and Hedging (Tables) Tables http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedging 60 false false R61.htm 9954489 - Disclosure - Lease Income (Tables) Sheet http://www.slgreen.com/role/LeaseIncomeTables Lease Income (Tables) Tables http://www.slgreen.com/role/LeaseIncome 61 false false R62.htm 9954490 - Disclosure - Benefit Plans (Tables) Sheet http://www.slgreen.com/role/BenefitPlansTables Benefit Plans (Tables) Tables http://www.slgreen.com/role/BenefitPlans 62 false false R63.htm 9954491 - Disclosure - Commitments and Contingencies (Tables) Sheet http://www.slgreen.com/role/CommitmentsandContingenciesTables Commitments and Contingencies (Tables) Tables http://www.slgreen.com/role/CommitmentsandContingencies 63 false false R64.htm 9954492 - Disclosure - Segment Information (Tables) Sheet http://www.slgreen.com/role/SegmentInformationTables Segment Information (Tables) Tables http://www.slgreen.com/role/SegmentInformation 64 false false R65.htm 9954493 - Disclosure - Organization and Basis of Presentation - Narrative (Details) Sheet http://www.slgreen.com/role/OrganizationandBasisofPresentationNarrativeDetails Organization and Basis of Presentation - Narrative (Details) Details 65 false false R66.htm 9954494 - Disclosure - Organization and Basis of Presentation - Schedule of Interests in Investment Properties (Details) Sheet http://www.slgreen.com/role/OrganizationandBasisofPresentationScheduleofInterestsinInvestmentPropertiesDetails Organization and Basis of Presentation - Schedule of Interests in Investment Properties (Details) Details 66 false false R67.htm 9954495 - Disclosure - Significant Accounting Policies - Investment in Commercial Real Estate Properties (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesInvestmentinCommercialRealEstatePropertiesNarrativeDetails Significant Accounting Policies - Investment in Commercial Real Estate Properties (Narrative) (Details) Details 67 false false R68.htm 9954496 - Disclosure - Significant Accounting Policies - Schedule of Estimated Useful Lives (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofEstimatedUsefulLivesDetails Significant Accounting Policies - Schedule of Estimated Useful Lives (Details) Details 68 false false R69.htm 9954497 - Disclosure - Significant Accounting Policies - Depreciation and Amortization of Right of Use Assets (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesDepreciationandAmortizationofRightofUseAssetsNarrativeDetails Significant Accounting Policies - Depreciation and Amortization of Right of Use Assets (Narrative) (Details) Details 69 false false R70.htm 9954498 - Disclosure - Significant Accounting Policies - Schedule of Identified Intangible Assets and Intangible Liabilities (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofIdentifiedIntangibleAssetsandIntangibleLiabilitiesDetails Significant Accounting Policies - Schedule of Identified Intangible Assets and Intangible Liabilities (Details) Details 70 false false R71.htm 9954499 - Disclosure - Significant Accounting Policies - Schedule of Estimated Annual Amortization of Acquired Above-market Leases, Net of Acquired Below-market Leases (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofEstimatedAnnualAmortizationofAcquiredAbovemarketLeasesNetofAcquiredBelowmarketLeasesDetails Significant Accounting Policies - Schedule of Estimated Annual Amortization of Acquired Above-market Leases, Net of Acquired Below-market Leases (Details) Details 71 false false R72.htm 9954500 - Disclosure - Significant Accounting Policies - Schedule of Estimated Annual Amortization of all Other Identifiable Assets (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofEstimatedAnnualAmortizationofallOtherIdentifiableAssetsDetails Significant Accounting Policies - Schedule of Estimated Annual Amortization of all Other Identifiable Assets (Details) Details 72 false false R73.htm 9954501 - Disclosure - Significant Accounting Policies - Schedule of Marketable Securities (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofMarketableSecuritiesDetails Significant Accounting Policies - Schedule of Marketable Securities (Details) Details 73 false false R74.htm 9954502 - Disclosure - Significant Accounting Policies - Investment in Marketable Securities (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesInvestmentinMarketableSecuritiesNarrativeDetails Significant Accounting Policies - Investment in Marketable Securities (Narrative) (Details) Details 74 false false R75.htm 9954503 - Disclosure - Significant Accounting Policies - Deferred Lease Costs (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesDeferredLeaseCostsNarrativeDetails Significant Accounting Policies - Deferred Lease Costs (Narrative) (Details) Details 75 false false R76.htm 9954504 - Disclosure - Significant Accounting Policies - Revenue Recognition (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesRevenueRecognitionNarrativeDetails Significant Accounting Policies - Revenue Recognition (Narrative) (Details) Details 76 false false R77.htm 9954505 - Disclosure - Significant Accounting Policies - Income Taxes (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesIncomeTaxesNarrativeDetails Significant Accounting Policies - Income Taxes (Narrative) (Details) Details 77 false false R78.htm 9954506 - Disclosure - Significant Accounting Policies - Concentrations of Credit Risk (Narrative) (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesConcentrationsofCreditRiskNarrativeDetails Significant Accounting Policies - Concentrations of Credit Risk (Narrative) (Details) Details 78 false false R79.htm 9954507 - Disclosure - Significant Accounting Policies - Schedule of Properties Contributed of Annualized Cash Rent (Details) Sheet http://www.slgreen.com/role/SignificantAccountingPoliciesScheduleofPropertiesContributedofAnnualizedCashRentDetails Significant Accounting Policies - Schedule of Properties Contributed of Annualized Cash Rent (Details) Details 79 false false R80.htm 9954508 - Disclosure - Property Acquisitions - Schedule of Properties Acquired in 2022 (Details) Sheet http://www.slgreen.com/role/PropertyAcquisitionsScheduleofPropertiesAcquiredin2022Details Property Acquisitions - Schedule of Properties Acquired in 2022 (Details) Details 80 false false R81.htm 9954509 - Disclosure - Property Acquisitions - Schedule of Properties Acquired in 2021 (Details) Sheet http://www.slgreen.com/role/PropertyAcquisitionsScheduleofPropertiesAcquiredin2021Details Property Acquisitions - Schedule of Properties Acquired in 2021 (Details) Details 81 false false R82.htm 9954510 - Disclosure - Properties Held for Sale and Property Dispositions - Schedule of Properties Sold (Details) Sheet http://www.slgreen.com/role/PropertiesHeldforSaleandPropertyDispositionsScheduleofPropertiesSoldDetails Properties Held for Sale and Property Dispositions - Schedule of Properties Sold (Details) Details 82 false false R83.htm 9954511 - Disclosure - Debt and Preferred Equity Investments - Schedule of Activity in Debt and Preferred Equity Investments (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofActivityinDebtandPreferredEquityInvestmentsDetails Debt and Preferred Equity Investments - Schedule of Activity in Debt and Preferred Equity Investments (Details) Details 83 false false R84.htm 9954512 - Disclosure - Debt and Preferred Equity Investments - Schedule of Debt and Preferred Equity Investments (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofDebtandPreferredEquityInvestmentsDetails Debt and Preferred Equity Investments - Schedule of Debt and Preferred Equity Investments (Details) Details 84 false false R85.htm 9954513 - Disclosure - Debt and Preferred Equity Investments - Schedule of Roll Forward of our Total Allowance for Loan Losses (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofRollForwardofourTotalAllowanceforLoanLossesDetails Debt and Preferred Equity Investments - Schedule of Roll Forward of our Total Allowance for Loan Losses (Details) Details 85 false false R86.htm 9954514 - Disclosure - Debt and Preferred Equity Investments - Narrative (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsNarrativeDetails Debt and Preferred Equity Investments - Narrative (Details) Details 86 false false R87.htm 9954515 - Disclosure - Debt and Preferred Equity Investments - Schedule of Carrying Value of Debt and Preferred Equity Investment Portfolio by Year of Origination and Risk Rating (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofCarryingValueofDebtandPreferredEquityInvestmentPortfoliobyYearofOriginationandRiskRatingDetails Debt and Preferred Equity Investments - Schedule of Carrying Value of Debt and Preferred Equity Investment Portfolio by Year of Origination and Risk Rating (Details) Details 87 false false R88.htm 9954516 - Disclosure - Debt and Preferred Equity Investments - Schedule of Debt Investments with an Aggregate Weighted Average Current Yield (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofDebtInvestmentswithanAggregateWeightedAverageCurrentYieldDetails Debt and Preferred Equity Investments - Schedule of Debt Investments with an Aggregate Weighted Average Current Yield (Details) Details 88 false false R89.htm 9954517 - Disclosure - Debt and Preferred Equity Investments - Schedule of Preferred Equity Investments with an Aggregate Weighted Average Current Yield (Details) Sheet http://www.slgreen.com/role/DebtandPreferredEquityInvestmentsScheduleofPreferredEquityInvestmentswithanAggregateWeightedAverageCurrentYieldDetails Debt and Preferred Equity Investments - Schedule of Preferred Equity Investments with an Aggregate Weighted Average Current Yield (Details) Details 89 false false R90.htm 9954518 - Disclosure - Investments in Unconsolidated Joint Ventures - Narrative (Details) Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesNarrativeDetails Investments in Unconsolidated Joint Ventures - Narrative (Details) Details 90 false false R91.htm 9954519 - Disclosure - Investments in Unconsolidated Joint Ventures - Schedule of General Information on Joint Ventures (Details) Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesScheduleofGeneralInformationonJointVenturesDetails Investments in Unconsolidated Joint Ventures - Schedule of General Information on Joint Ventures (Details) Details 91 false false R92.htm 9954520 - Disclosure - Investments in Unconsolidated Joint Ventures - Schedule of Investments in Unconsolidated Joint Ventures Sold (Details) Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesScheduleofInvestmentsinUnconsolidatedJointVenturesSoldDetails Investments in Unconsolidated Joint Ventures - Schedule of Investments in Unconsolidated Joint Ventures Sold (Details) Details 92 false false R93.htm 9954521 - Disclosure - Investments in Unconsolidated Joint Ventures - Schedule of Mortgage Notes and Other Loans Payable Collateralized by the Respective Joint Venture Properties and Assignment of Leases (Details) Notes http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesScheduleofMortgageNotesandOtherLoansPayableCollateralizedbytheRespectiveJointVenturePropertiesandAssignmentofLeasesDetails Investments in Unconsolidated Joint Ventures - Schedule of Mortgage Notes and Other Loans Payable Collateralized by the Respective Joint Venture Properties and Assignment of Leases (Details) Details 93 false false R94.htm 9954522 - Disclosure - Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) Sheet http://www.slgreen.com/role/InvestmentsinUnconsolidatedJointVenturesSchedulesofCombinedFinancialStatementsfortheUnconsolidatedJointVenturesDetails Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) Details 94 false false R95.htm 9954523 - Disclosure - Deferred Costs (Details) Sheet http://www.slgreen.com/role/DeferredCostsDetails Deferred Costs (Details) Details http://www.slgreen.com/role/DeferredCostsTables 95 false false R96.htm 9954524 - Disclosure - Mortgages and Other Loans Payable - Schedule of Mortgages and Other Loans Payable (Details) Sheet http://www.slgreen.com/role/MortgagesandOtherLoansPayableScheduleofMortgagesandOtherLoansPayableDetails Mortgages and Other Loans Payable - Schedule of Mortgages and Other Loans Payable (Details) Details 96 false false R97.htm 9954525 - Disclosure - Mortgages and Other Loans Payable - Narrative (Details) Sheet http://www.slgreen.com/role/MortgagesandOtherLoansPayableNarrativeDetails Mortgages and Other Loans Payable - Narrative (Details) Details 97 false false R98.htm 9954526 - Disclosure - Corporate Indebtedness - Additional Information (Details) Sheet http://www.slgreen.com/role/CorporateIndebtednessAdditionalInformationDetails Corporate Indebtedness - Additional Information (Details) Details 98 false false R99.htm 9954527 - Disclosure - Corporate Indebtedness - 2022 Term Loan (Details) Sheet http://www.slgreen.com/role/CorporateIndebtedness2022TermLoanDetails Corporate Indebtedness - 2022 Term Loan (Details) Details 99 false false R100.htm 9954528 - Disclosure - Corporate Indebtedness - Senior Unsecured Notes (Details) Notes http://www.slgreen.com/role/CorporateIndebtednessSeniorUnsecuredNotesDetails Corporate Indebtedness - Senior Unsecured Notes (Details) Details 100 false false R101.htm 9954529 - Disclosure - Corporate Indebtedness - Junior Subordinated Deferrable Interest Debentures and Principal Maturities (Details) Sheet http://www.slgreen.com/role/CorporateIndebtednessJuniorSubordinatedDeferrableInterestDebenturesandPrincipalMaturitiesDetails Corporate Indebtedness - Junior Subordinated Deferrable Interest Debentures and Principal Maturities (Details) Details 101 false false R102.htm 9954530 - Disclosure - Corporate Indebtedness - Schedule of Consolidated Interest Expense, Excluding Capitalized Interest (Details) Sheet http://www.slgreen.com/role/CorporateIndebtednessScheduleofConsolidatedInterestExpenseExcludingCapitalizedInterestDetails Corporate Indebtedness - Schedule of Consolidated Interest Expense, Excluding Capitalized Interest (Details) Details 102 false false R103.htm 9954531 - Disclosure - Related Party Transactions (Details) Sheet http://www.slgreen.com/role/RelatedPartyTransactionsDetails Related Party Transactions (Details) Details http://www.slgreen.com/role/RelatedPartyTransactionsTables 103 false false R104.htm 9954532 - Disclosure - Noncontrolling Interests on the Company's Consolidated Financial Statements - Additional Information (Details) Sheet http://www.slgreen.com/role/NoncontrollingInterestsontheCompanysConsolidatedFinancialStatementsAdditionalInformationDetails Noncontrolling Interests on the Company's Consolidated Financial Statements - Additional Information (Details) Details 104 false false R105.htm 9954533 - Disclosure - Noncontrolling Interests on the Company's Consolidated Financial Statements - Preferred Unit Activity (Details) Sheet http://www.slgreen.com/role/NoncontrollingInterestsontheCompanysConsolidatedFinancialStatementsPreferredUnitActivityDetails Noncontrolling Interests on the Company's Consolidated Financial Statements - Preferred Unit Activity (Details) Details 105 false false R106.htm 9954534 - Disclosure - Stockholders' Equity of the Company - Additional Information (Details) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyAdditionalInformationDetails Stockholders' Equity of the Company - Additional Information (Details) Details 106 false false R107.htm 9954535 - Disclosure - Stockholders' Equity of the Company - Stock Repurchase Program (Details) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyStockRepurchaseProgramDetails Stockholders' Equity of the Company - Stock Repurchase Program (Details) Details 107 false false R108.htm 9954536 - Disclosure - Stockholders' Equity of the Company - At-the-Market Equity Offering Program and Perpetual Preferred Stock (Details) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyAttheMarketEquityOfferingProgramandPerpetualPreferredStockDetails Stockholders' Equity of the Company - At-the-Market Equity Offering Program and Perpetual Preferred Stock (Details) Details 108 false false R109.htm 9954537 - Disclosure - Stockholders' Equity of the Company - Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments (Details) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyScheduleofCommonStockIssuedandProceedsReceivedDividendReinvestmentsDetails Stockholders' Equity of the Company - Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments (Details) Details 109 false false R110.htm 9954538 - Disclosure - Stockholders' Equity of the Company - Earnings per Share (Details) Sheet http://www.slgreen.com/role/StockholdersEquityoftheCompanyEarningsperShareDetails Stockholders' Equity of the Company - Earnings per Share (Details) Details 110 false false R111.htm 9954539 - Disclosure - Partners' Capital of the Operating Partnership - Additional Information (Details) Sheet http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnershipAdditionalInformationDetails Partners' Capital of the Operating Partnership - Additional Information (Details) Details 111 false false R112.htm 9954540 - Disclosure - Partners' Capital of the Operating Partnership - EPS (Details) Sheet http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnershipEPSDetails Partners' Capital of the Operating Partnership - EPS (Details) Details http://www.slgreen.com/role/PartnersCapitaloftheOperatingPartnershipTables 112 false false R113.htm 9954541 - Disclosure - Share-based Compensation - Additional Information (Details) Sheet http://www.slgreen.com/role/SharebasedCompensationAdditionalInformationDetails Share-based Compensation - Additional Information (Details) Details 113 false false R114.htm 9954542 - Disclosure - Share-based Compensation - Activity (Details) Sheet http://www.slgreen.com/role/SharebasedCompensationActivityDetails Share-based Compensation - Activity (Details) Details 114 false false R115.htm 9954543 - Disclosure - Accumulated Other Comprehensive Income (Details) Sheet http://www.slgreen.com/role/AccumulatedOtherComprehensiveIncomeDetails Accumulated Other Comprehensive Income (Details) Details http://www.slgreen.com/role/AccumulatedOtherComprehensiveIncomeTables 115 false false R116.htm 9954544 - Disclosure - Fair Value Measurements (Details) Sheet http://www.slgreen.com/role/FairValueMeasurementsDetails Fair Value Measurements (Details) Details http://www.slgreen.com/role/FairValueMeasurementsTables 116 false false R117.htm 9954545 - Disclosure - Financial Instruments: Derivatives and Hedging - Schedule of Notional and Fair Value of Derivative Financial Instruments and Foreign Currency Hedges (Details) Sheet http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedgingScheduleofNotionalandFairValueofDerivativeFinancialInstrumentsandForeignCurrencyHedgesDetails Financial Instruments: Derivatives and Hedging - Schedule of Notional and Fair Value of Derivative Financial Instruments and Foreign Currency Hedges (Details) Details 117 false false R118.htm 9954546 - Disclosure - Financial Instruments: Derivatives and Hedging (Details) Sheet http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedgingDetails Financial Instruments: Derivatives and Hedging (Details) Details http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedgingTables 118 false false R119.htm 9954547 - Disclosure - Financial Instruments: Derivatives and Hedging - Schedule of Effect of Derivative Financial Instruments on Consolidated Statements of Income (Details) Sheet http://www.slgreen.com/role/FinancialInstrumentsDerivativesandHedgingScheduleofEffectofDerivativeFinancialInstrumentsonConsolidatedStatementsofIncomeDetails Financial Instruments: Derivatives and Hedging - Schedule of Effect of Derivative Financial Instruments on Consolidated Statements of Income (Details) Details 119 false false R120.htm 9954548 - Disclosure - Lease Income - Future Minimum Rents (Details) Sheet http://www.slgreen.com/role/LeaseIncomeFutureMinimumRentsDetails Lease Income - Future Minimum Rents (Details) Details 120 false false R121.htm 9954549 - Disclosure - Lease Income - Lease Income (Details) Sheet http://www.slgreen.com/role/LeaseIncomeLeaseIncomeDetails Lease Income - Lease Income (Details) Details 121 false false R122.htm 9954550 - Disclosure - Lease Income - Sales Type Lease (Details) Sheet http://www.slgreen.com/role/LeaseIncomeSalesTypeLeaseDetails Lease Income - Sales Type Lease (Details) Details 122 false false R123.htm 9954551 - Disclosure - Benefit Plans (Details) Sheet http://www.slgreen.com/role/BenefitPlansDetails Benefit Plans (Details) Details http://www.slgreen.com/role/BenefitPlansTables 123 false false R124.htm 9954552 - Disclosure - Commitments and Contingencies (Details) Sheet http://www.slgreen.com/role/CommitmentsandContingenciesDetails Commitments and Contingencies (Details) Details http://www.slgreen.com/role/CommitmentsandContingenciesTables 124 false false R125.htm 9954553 - Disclosure - Commitments and Contingencies - Lease Cost (Details) Sheet http://www.slgreen.com/role/CommitmentsandContingenciesLeaseCostDetails Commitments and Contingencies - Lease Cost (Details) Details 125 false false R126.htm 9954554 - Disclosure - Segment Information - Additional Information (Details) Sheet http://www.slgreen.com/role/SegmentInformationAdditionalInformationDetails Segment Information - Additional Information (Details) Details 126 false false R127.htm 9954555 - Disclosure - Schedule III - Real Estate and Accumulated Depreciation (Details) Sheet http://www.slgreen.com/role/ScheduleIIIRealEstateandAccumulatedDepreciationDetails Schedule III - Real Estate and Accumulated Depreciation (Details) Details http://www.slgreen.com/role/ScheduleIIIRealEstateandAccumulatedDepreciation 127 false false R128.htm 9954556 - Disclosure - Schedule III - Real Estate and Accumulated Depreciation (Activity in Real Estate and Accumulated Depreciation) (Details) Sheet http://www.slgreen.com/role/ScheduleIIIRealEstateandAccumulatedDepreciationActivityinRealEstateandAccumulatedDepreciationDetails Schedule III - Real Estate and Accumulated Depreciation (Activity in Real Estate and Accumulated Depreciation) (Details) Details http://www.slgreen.com/role/ScheduleIIIRealEstateandAccumulatedDepreciation 128 false false All Reports Book All Reports slg-20231231.htm slg-20231231.xsd slg-20231231_cal.xml slg-20231231_def.xml slg-20231231_lab.xml slg-20231231_pre.xml http://fasb.org/srt/2023 http://fasb.org/us-gaap/2023 http://xbrl.sec.gov/dei/2023 true true