Consolidated Statements of Cash Flows (Partnership) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities
Net income (loss)	$ 30,222	$ (599,337)	$ (76,303)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	214,062	255,647	223,984
Equity in net loss from unconsolidated joint ventures	179,695	76,509	57,958
Distributions of cumulative earnings from unconsolidated joint ventures	12,992	9,897	780
Equity in net (gain) loss on sale of interest in unconsolidated joint venture/real estate	(208,144)	13,368	131
Purchase price and other fair value adjustments	(88,966)	17,260	8,118
Depreciable real estate reserves and impairments	104,071	382,374	6,313
(Gain) loss on sale of real estate, net	(3,025)	32,370	84,485
Loan loss and other investment reserves, net of recoveries	0	6,890	0
(Gain) loss on early extinguishment of debt	(43,762)	870	0
Deferred rents receivable	(1,535)	(17,903)	(5,749)
Non-cash lease expense	20,290	20,435	22,403
Other non-cash adjustments	46,219	28,174	(5,676)
Changes in operating assets and liabilities:
Tenant and other receivables	(11,804)	(1,725)	14,370
Related party receivables	(11,414)	15,788	6,666
Deferred lease costs	(29,271)	(17,427)	(21,792)
Other assets	15,968	(1,922)	(28,204)
Accounts payable, accrued expenses, other liabilities and security deposits	(74,501)	11,974	(30,839)
Deferred revenue	(4,799)	8,057	18,332
Lease liability - operating leases	(16,703)	(11,796)	1,111
Net cash provided by operating activities	129,595	229,503	276,088
Investing Activities
Acquisitions of real estate property	0	0	(64,491)
Additions to land, buildings and improvements	(211,869)	(259,663)	(300,770)
Acquisition deposits and deferred purchase price	(23,050)	0	0
Investments in unconsolidated joint ventures	(451,233)	(184,481)	(184,518)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	161,474	140,569	141,742
Net proceeds from disposition of real estate/joint venture interest	729,025	557,611	626,364
Cash and restricted cash assumed from acquisition and consolidation of real estate investment	19,017	0	60,494
Proceeds from sale or redemption of marketable securities	0	0	15,626
Investments in marketable securities	(12,368)	0	0
Investments in real estate loans held by consolidated securitization vehicles	(117,894)	0	0
Other investments	(21,535)	(17,334)	1,432
Origination of debt and preferred equity investments	(16,310)	(65,357)	(51,367)
Repayments or redemption of debt and preferred equity investments	63,496	0	181,293
Net cash provided by investing activities	118,753	171,345	425,805
Financing Activities
Proceeds from mortgages and other loans payable	4,450	0	381,980
Repayments of mortgages and other loans payable	(68,977)	(25,826)	(292,364)
Proceeds from revolving credit facility, term loans and senior unsecured notes	1,170,000	538,000	1,524,000
Repayments of revolving credit facility, term loans and senior unsecured notes	(1,510,000)	(828,000)	(1,864,000)
Proceeds from stock options exercised and DRSPP issuance	52,308	525	525
Proceeds from issuance of common stock	386,790	0	0
Repurchase of common units	0	0	(151,197)
Redemption of preferred units	(2,503)	(11,700)	(17,967)
Redemption of OP units	(38,177)	(9,076)	(40,901)
Distributions to noncontrolling interests in other partnerships	(11,053)	(2,777)	(4,699)
Contributions from noncontrolling interests in other partnerships	6,584	6,932	52,164
Acquisition of subsidiary interest from noncontrolling interest	(7,289)	0	(29,817)
Distributions paid on common and preferred units	(218,823)	(230,931)	(262,136)
Other obligation related to secured borrowing	0	129,656	77,874
Tax withholdings related to restricted share awards	(182)	0	(3,915)
Deferred loan costs	(1,442)	(1,407)	(8,098)
Net cash used in financing activities	(252,229)	(449,383)	(654,823)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(3,881)	(48,535)	47,070
Cash, cash equivalents, and restricted cash at beginning of year	335,519	384,054	336,984
Cash, cash equivalents, and restricted cash at end of period	331,638	335,519	384,054
Supplemental cash flow disclosures:
Interest paid	200,752	229,119	169,519
Income taxes paid	9,001	7,815	5,358
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Exchange of preferred equity investment for real estate or equity in joint venture	0	0	190,652
Exchange of debt investment for real estate or equity in joint venture	0	349,946	193,995
Assumption of mortgage and mezzanine loans	0	0	1,712,750
Tenant improvements and capital expenditures payable	0	0	18,518
Acquisition of subsidiary interest from noncontrolling interest	1,927	0	0
Consolidation of a subsidiary	50,377	0	0
Investment in joint venture	10,639	0	47,135
Deconsolidation of a subsidiary	0	101,351	0
Deconsolidation of subsidiary debt	0	1,712,750	0
Debt and preferred equity investments	1,133	0	302
Extinguishment of debt	46,835	0	0
Removal of fully depreciated commercial real estate properties	6,903	16,313	30,359
Contribution to consolidated joint venture by noncontrolling interest	72	8,134	0
Share repurchase or redemption payable	9,514	9,513	0
Recognition of right of use assets and related lease liabilities	0	0	57,938
Consolidation of securitization vehicle assets	600,521	0	0
Consolidation of securitization vehicle liabilities	600,521	0	0
Cash and cash equivalents	184,294	221,823	203,273
Restricted cash	147,344	113,696	180,781
Total cash, cash equivalents, and restricted cash	331,638	335,519	384,054
SL Green Operating Partnership
Operating Activities
Net income (loss)	30,222	(599,337)	(76,303)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	214,062	255,647	223,984
Equity in net loss from unconsolidated joint ventures	179,695	76,509	57,958
Distributions of cumulative earnings from unconsolidated joint ventures	12,992	9,897	780
Equity in net (gain) loss on sale of interest in unconsolidated joint venture/real estate	(208,144)	13,368	131
Purchase price and other fair value adjustments	(88,966)	17,260	8,118
Depreciable real estate reserves and impairments	104,071	382,374	6,313
(Gain) loss on sale of real estate, net	(3,025)	32,370	84,485
Loan loss and other investment reserves, net of recoveries	0	6,890	0
(Gain) loss on early extinguishment of debt	(43,762)	870	0
Deferred rents receivable	(1,535)	(17,903)	(5,749)
Non-cash lease expense	20,290	20,435	22,403
Other non-cash adjustments	46,219	28,174	(5,676)
Changes in operating assets and liabilities:
Tenant and other receivables	(11,804)	(1,725)	14,370
Related party receivables	(11,414)	15,788	6,666
Deferred lease costs	(29,271)	(17,427)	(21,792)
Other assets	15,968	(1,922)	(28,204)
Accounts payable, accrued expenses, other liabilities and security deposits	(74,501)	11,974	(30,839)
Deferred revenue	(4,799)	8,057	18,332
Lease liability - operating leases	(16,703)	(11,796)	1,111
Net cash provided by operating activities	129,595	229,503	276,088
Investing Activities
Acquisitions of real estate property	0	0	(64,491)
Additions to land, buildings and improvements	(211,869)	(259,663)	(300,770)
Acquisition deposits and deferred purchase price	(23,050)	0	0
Investments in unconsolidated joint ventures	(451,233)	(184,481)	(184,518)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	161,474	140,569	141,742
Net proceeds from disposition of real estate/joint venture interest	729,025	557,611	626,364
Cash and restricted cash assumed from acquisition and consolidation of real estate investment	19,017	0	60,494
Proceeds from sale or redemption of marketable securities	0	0	15,626
Investments in marketable securities	(12,368)	0	0
Investments in real estate loans held by consolidated securitization vehicles	(117,894)	0	0
Other investments	(21,535)	(17,334)	1,432
Origination of debt and preferred equity investments	(16,310)	(65,357)	(51,367)
Repayments or redemption of debt and preferred equity investments	63,496	0	181,293
Net cash provided by investing activities	118,753	171,345	425,805
Financing Activities
Proceeds from mortgages and other loans payable	4,450	0	381,980
Repayments of mortgages and other loans payable	(68,977)	(25,826)	(292,364)
Proceeds from revolving credit facility, term loans and senior unsecured notes	1,170,000	538,000	1,524,000
Repayments of revolving credit facility, term loans and senior unsecured notes	(1,510,000)	(828,000)	(1,864,000)
Proceeds from stock options exercised and DRSPP issuance	52,308	525	525
Repurchase of common units	0	0	(151,197)
Redemption of preferred units	(2,503)	(11,700)	(17,967)
Redemption of OP units	(38,177)	(9,076)	(40,901)
Distributions to noncontrolling interests in other partnerships	(11,053)	(2,777)	(4,699)
Contributions from noncontrolling interests in other partnerships	6,584	6,932	52,164
Acquisition of subsidiary interest from noncontrolling interest	(7,289)	0	(29,817)
Distributions paid on common and preferred units	(232,738)	(245,710)	(278,408)
Other obligation related to secured borrowing	0	129,656	77,874
Tax withholdings related to restricted share awards	(182)	0	(3,915)
Deferred loan costs	(1,442)	(1,407)	(8,098)
Net cash used in financing activities	(252,229)	(449,383)	(654,823)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(3,881)	(48,535)	47,070
Cash, cash equivalents, and restricted cash at beginning of year	335,519	384,054	336,984
Cash, cash equivalents, and restricted cash at end of period	331,638	335,519	384,054
Supplemental cash flow disclosures:
Interest paid	200,752	229,119	169,519
Income taxes paid	9,001	7,815	5,358
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Exchange of preferred equity investment for real estate or equity in joint venture	0	0	190,652
Exchange of debt investment for real estate or equity in joint venture	0	349,946	193,995
Assumption of mortgage and mezzanine loans	0	0	1,712,750
Issuance of special distribution paid in units	0	0	160,620
Tenant improvements and capital expenditures payable	0	0	18,518
Measurement adjustment for redeemable noncontrolling interest	107,632	15,486	39,974
Investment in joint venture	10,639	0	47,135
Deconsolidation of a subsidiary	0	101,351	0
Deconsolidation of subsidiary debt	0	1,712,750	0
Debt and preferred equity investments	1,133	0	302
Extinguishment of debt	46,835	0	0
Removal of fully depreciated commercial real estate properties	6,903	16,313	30,359
Contribution to consolidated joint venture by noncontrolling interest	72	8,134	0
Share repurchase or redemption payable	9,514	9,513	0
Recognition of right of use assets and related lease liabilities	0	0	57,938
Consolidation of securitization vehicle assets	600,521	0	0
Consolidation of securitization vehicle liabilities	600,521	0	0
Cash and cash equivalents	184,294	221,823	203,273
Restricted cash	147,344	113,696	180,781
Total cash, cash equivalents, and restricted cash	$ 331,638	$ 335,519	$ 384,054