Consolidated Statements of Cash Flows (Partnership) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net (loss) income	$ (76,303)	$ 480,632	$ 414,758
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	223,123	228,293	325,462
Equity in net loss from unconsolidated joint ventures	57,958	55,402	25,195
Distributions of cumulative earnings from unconsolidated joint ventures	780	824	679
Equity in net loss (gain) on sale of interest in unconsolidated joint venture interest/real estate	131	32,757	(2,961)
Purchase price and other fair value adjustments	8,118	(210,070)	(187,522)
Depreciable real estate reserves and impairments	6,313	23,794	60,454
Loss (gain) on sale of real estate, net	84,485	(287,417)	(215,506)
Loan loss reserves and other investment reserves, net of recoveries	0	2,931	35,298
Loss on early extinguishment of debt	0	1,551	0
Deferred rents receivable	(5,749)	(6,701)	(7,582)
Non-cash lease expense	22,403	17,234	11,984
Other non-cash adjustments	(5,676)	37,164	15,178
Changes in operating assets and liabilities:
Tenant and other receivables	14,370	(20,561)	(17,074)
Related party receivables	6,666	(8,727)	1,451
Deferred lease costs	(21,792)	(10,117)	(20,900)
Other assets	(27,343)	20,345	(26,137)
Accounts payable, accrued expenses, other liabilities and security deposits	(30,839)	(66,387)	132,171
Deferred revenue	18,332	(1,727)	20,657
Change in lease liability - operating leases	1,111	(33,241)	(11,369)
Net cash provided by operating activities	276,088	255,979	554,236
Investing Activities
Acquisitions of real estate property	(64,491)	(152,791)	(86,846)
Additions to land, buildings and improvements	(300,770)	(302,486)	(458,140)
Investments in unconsolidated joint ventures	(184,518)	(88,872)	(70,315)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	141,742	770,604	124,572
Net proceeds from disposition of real estate/joint venture interest	626,364	651,594	1,112,382
Cash and restricted cash assumed from acquisition of real estate investment	60,494	0	0
Cash assumed from consolidation of real estate investment	0	9,475	0
Proceeds from sale or redemption of marketable securities	15,626	4,528	0
Purchases of marketable securities	0	(10,000)	0
Other investments	1,432	40,200	32,479
Origination of debt and preferred equity investments	(51,367)	(95,695)	(360,953)
Repayments or redemption of debt and preferred equity investments	181,293	167,024	763,251
Net cash provided by investing activities	425,805	993,581	1,056,430
Financing Activities
Proceeds from mortgages and other loans payable	381,980	39,689	1,181,892
Repayments of mortgages and other loans payable	(292,364)	(375,044)	(1,186,828)
Proceeds from revolving credit facility and senior unsecured notes	1,524,000	1,488,000	1,495,000
Repayments of revolving credit facility and senior unsecured notes	(1,864,000)	(1,808,000)	(1,875,000)
Proceeds from stock options exercised and DRSPP issuance	525	1,556	1,006
Repurchase of common stock	(151,197)	(341,403)	(528,483)
Redemption of preferred stock	(17,967)	(6,040)	(82,750)
Redemption of OP units	(40,901)	(25,703)	(27,342)
Distributions to noncontrolling interests in other partnerships	(4,699)	(6,631)	(85,468)
Contributions from noncontrolling interests in other partnerships	52,164	336	12,477
Acquisition of subsidiary interest from noncontrolling interest	(29,817)	0	(1,536)
Dividends paid on common and preferred stock	(262,136)	(271,075)	(293,996)
Other obligation related to secured borrowing	77,874	51,862	0
Tax withholdings related to restricted share awards	(3,915)	(2,990)	(4,752)
Deferred loan costs	(8,098)	(13,745)	(70,036)
Principal payments of on financing lease liabilities	0	(434)	(833)
Net cash used in financing activities	(654,823)	(1,285,371)	(1,479,301)
Net increase (decrease) in cash, cash equivalents, and restricted cash	47,070	(35,811)	131,365
Cash, cash equivalents, and restricted cash at beginning of year	336,984	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	384,054	336,984	372,795
Supplemental cash flow disclosures:
Interest paid	169,519	152,773	201,348
Income taxes paid	5,358	4,405	2,296
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	0	8,744
Redemption of units in the Operating Partnership for a joint venture sale	0	27,586	0
Exchange of preferred equity investment for real estate or equity in joint venture	190,652	0	119,497
Exchange of debt investment for real estate or equity in joint venture	193,995	9,468	122,796
Assumption of mortgage and mezzanine loans	1,712,750	60,000	0
Tenant improvements and capital expenditures payable	18,518	7,580	1,665
Fair value adjustment to noncontrolling interest in the Operating Partnership	39,974	9,851	32,598
Investment in joint venture	47,135	0	0
Deconsolidation of a subsidiary	0	66,837	854,437
Deconsolidation of a subsidiary mortgage	0	510,000	5,593
Mortgages assumed in connection with sale of real estate	0	0	250,000
Seller financed purchases	0	0	100,000
Debt and preferred equity investments	302	8,372	9,014
Transfer of assets related to assets held for sale	0	140,855	0
Reversal of assets held for sale	0	0	391,664
Transfer of liabilities related to assets held for sale	0	64,120	0
Extinguishment of debt in connection with property dispositions	0	53,548	0
Consolidation of real estate investment	0	119,444	0
Removal of fully depreciated commercial real estate properties	30,359	19,831	66,169
Sale of interest in partially owned entity	0	4,476	0
Distributions to noncontrolling interests	0	358	6,613
Share repurchase payable	0	0	3,779
Recognition of sales-type leases and related lease liabilities	0	0	119,725
Recognition of right of use assets and related lease liabilities	57,938	537,344	61,990
Cash and cash equivalents	203,273	251,417	266,059
Restricted cash	180,781	85,567	106,736
Total cash, cash equivalents, and restricted cash	384,054	336,984	372,795
SL Green Operating Partnership
Operating Activities
Net (loss) income	(76,303)	480,632	414,758
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	223,123	228,293	325,462
Equity in net loss from unconsolidated joint ventures	57,958	55,402	25,195
Distributions of cumulative earnings from unconsolidated joint ventures	780	824	679
Equity in net loss (gain) on sale of interest in unconsolidated joint venture interest/real estate	131	32,757	(2,961)
Purchase price and other fair value adjustments	8,118	(210,070)	(187,522)
Depreciable real estate reserves and impairments	6,313	23,794	60,454
Loss (gain) on sale of real estate, net	84,485	(287,417)	(215,506)
Loan loss reserves and other investment reserves, net of recoveries	0	2,931	35,298
Loss on early extinguishment of debt	0	1,551	0
Deferred rents receivable	(5,749)	(6,701)	(7,582)
Non-cash lease expense	22,403	17,234	11,984
Other non-cash adjustments	(5,676)	37,164	15,178
Changes in operating assets and liabilities:
Tenant and other receivables	14,370	(20,561)	(17,074)
Related party receivables	6,666	(8,727)	1,451
Deferred lease costs	(21,792)	(10,117)	(20,900)
Other assets	(27,343)	20,345	(26,137)
Accounts payable, accrued expenses, other liabilities and security deposits	(30,839)	(66,387)	132,171
Deferred revenue	18,332	(1,727)	20,657
Change in lease liability - operating leases	1,111	(33,241)	(11,369)
Net cash provided by operating activities	276,088	255,979	554,236
Investing Activities
Acquisitions of real estate property	(64,491)	(152,791)	(86,846)
Additions to land, buildings and improvements	(300,770)	(302,486)	(458,140)
Investments in unconsolidated joint ventures	(184,518)	(88,872)	(70,315)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	141,742	770,604	124,572
Net proceeds from disposition of real estate/joint venture interest	626,364	651,594	1,112,382
Cash and restricted cash assumed from acquisition of real estate investment	60,494	0	0
Cash assumed from consolidation of real estate investment	0	9,475	0
Proceeds from sale or redemption of marketable securities	15,626	4,528	0
Purchases of marketable securities	0	(10,000)	0
Other investments	1,432	40,200	32,479
Origination of debt and preferred equity investments	(51,367)	(95,695)	(360,953)
Repayments or redemption of debt and preferred equity investments	181,293	167,024	763,251
Net cash provided by investing activities	425,805	993,581	1,056,430
Financing Activities
Proceeds from mortgages and other loans payable	381,980	39,689	1,181,892
Repayments of mortgages and other loans payable	(292,364)	(375,044)	(1,186,828)
Proceeds from revolving credit facility and senior unsecured notes	1,524,000	1,488,000	1,495,000
Repayments of revolving credit facility and senior unsecured notes	(1,864,000)	(1,808,000)	(1,875,000)
Proceeds from stock options exercised and DRSPP issuance	525	1,556	1,006
Repurchase of common stock	(151,197)	(341,403)	(528,483)
Redemption of preferred stock	(17,967)	(6,040)	(82,750)
Redemption of OP units	(40,901)	(25,703)	(27,342)
Distributions to noncontrolling interests in other partnerships	(4,699)	(6,631)	(85,468)
Contributions from noncontrolling interests in other partnerships	52,164	336	12,477
Acquisition of subsidiary interest from noncontrolling interest	(29,817)	0	(1,536)
Dividends paid on common and preferred stock	(278,408)	(286,824)	(306,648)
Other obligation related to secured borrowing	77,874	51,862	0
Tax withholdings related to restricted share awards	(3,915)	(2,990)	(4,752)
Deferred loan costs	(8,098)	(13,745)	(70,036)
Principal payments of on financing lease liabilities	0	(434)	(833)
Net cash used in financing activities	(654,823)	(1,285,371)	(1,479,301)
Net increase (decrease) in cash, cash equivalents, and restricted cash	47,070	(35,811)	131,365
Cash, cash equivalents, and restricted cash at beginning of year	336,984	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	384,054	336,984	372,795
Supplemental cash flow disclosures:
Interest paid	169,519	152,773	201,348
Income taxes paid	5,358	4,405	2,296
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	0	8,744
Redemption of units in the Operating Partnership for a joint venture sale	0	27,586	0
Exchange of preferred equity investment for real estate or equity in joint venture	190,652	0	119,497
Exchange of debt investment for real estate or equity in joint venture	193,995	9,468	122,796
Assumption of mortgage and mezzanine loans	1,712,750	60,000	0
Issuance of special distribution paid in units	160,620	121,418	0
Tenant improvements and capital expenditures payable	18,518	7,580	1,665
Fair value adjustment to noncontrolling interest in the Operating Partnership	39,974	9,851	32,598
Investment in joint venture	47,135	0	0
Deconsolidation of a subsidiary	0	66,837	854,437
Deconsolidation of a subsidiary mortgage	0	510,000	5,593
Mortgages assumed in connection with sale of real estate	0	0	250,000
Seller financed purchases	0	0	100,000
Debt and preferred equity investments	302	8,372	9,014
Transfer of assets related to assets held for sale	0	140,855	0
Reversal of assets held for sale	0	0	391,664
Transfer of liabilities related to assets held for sale	0	64,120	0
Extinguishment of debt in connection with property dispositions	0	53,548	0
Consolidation of real estate investment	0	119,444	0
Removal of fully depreciated commercial real estate properties	30,359	19,831	66,169
Sale of interest in partially owned entity	0	4,476	0
Distributions to noncontrolling interests	0	358	6,613
Share repurchase payable	0	0	3,779
Recognition of sales-type leases and related lease liabilities	0	0	119,725
Recognition of right of use assets and related lease liabilities	57,938	537,344	61,990
Cash and cash equivalents	203,273	251,417	266,059
Restricted cash	180,781	85,567	106,736
Total cash, cash equivalents, and restricted cash	$ 384,054	$ 336,984	$ 372,795