Consolidated Statements of Cash Flows (Partnership) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Operating Activities
Net loss	$ (379,228)	$ (37,949)	$ (417,585)	$ (24,464)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization			151,807	97,762
Equity in net loss from unconsolidated joint ventures	21,932	4,550	29,344	9,265
Distributions of cumulative earnings from unconsolidated joint ventures			409	343
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	0	131	79	131
Purchase price and other fair value adjustments			17,170	6,231
Depreciable real estate reserves and impairment			305,916	0
Loss on sale of real estate, net	26,678	64,378	28,329	65,380
Loan loss and other investment reserves, net of recoveries	0	0	6,890	0	$ 0
Deferred rents receivable			(14,357)	1,075
Non-cash lease expense			10,550	12,080
Other non-cash adjustments			(2,523)	(10,406)
Changes in operating assets and liabilities:
Tenant and other receivables			(3,805)	14,767
Related party receivables			(893)	1,458
Deferred lease costs			(5,891)	(6,922)
Other assets			1,235	(2,651)
Accounts payable, accrued expenses, other liabilities and security deposits			2,697	19,767
Deferred revenue			(585)	(2,672)
Lease liability - operating leases			(4,795)	1,291
Net cash provided by operating activities			103,992	182,435
Investing Activities
Additions to land, buildings and improvements			(134,190)	(126,957)
Investments in unconsolidated joint ventures			(46,977)	(135,365)
Distributions in excess of cumulative earnings from unconsolidated joint ventures			72,823	64,976
Net proceeds from disposition of real estate/joint venture interest			97,563	353,853
Other investments			(17,779)	1,507
Origination of debt and preferred equity investments			(10,308)	(29,095)
Repayments or redemption of debt and preferred equity investments			0	6,405
Net cash (used in) provided by investing activities			(38,868)	135,324
Financing Activities
Proceeds from mortgages and other loans payable			0	184,196
Repayments of mortgages and other loans payable			(2,899)	(91,770)
Proceeds from revolving credit facility and unsecured notes			223,000	332,000
Repayments of revolving credit facility and unsecured notes			(218,000)	(592,000)
Proceeds from stock options exercised and DRSPP issuance			342	199
Repurchase of common units			0	(151,197)
Redemption of preferred units			(11,700)	(17,968)
Redemption of OP units			(5,250)	(18,334)
Distributions to noncontrolling interests in other partnerships			(763)	(3,020)
Contributions from noncontrolling interests in other partnerships			314	51,348
Distributions paid on common and preferred units			(114,983)	(131,556)
Other obligations related to secured borrowing			0	77,874
Tax withholdings related to restricted share awards			0	(3,891)
Deferred loan costs			(630)	(4,991)
Net cash used in financing activities			(138,119)	(377,682)
Net decrease in cash, cash equivalents, and restricted cash			(72,995)	(59,923)
Cash, cash equivalents, and restricted cash at beginning of year			384,054	336,984	336,984
Cash, cash equivalents, and restricted cash at end of period	311,059	277,061	311,059	277,061	384,054
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of special distribution paid primarily in units			0	160,620
Tenant improvements and capital expenditures payable			0	10,295
Fair value adjustment to noncontrolling interest in the Operating Partnership			11,198	5,085
Contribution to consolidated joint venture interest			8,134	0
Removal of fully depreciated commercial real estate properties			7,747	3,597
Cash and cash equivalents	191,979	189,360	191,979	189,360	203,273
Restricted cash	119,080	87,701	119,080	87,701	180,781
Total cash, cash equivalents, and restricted cash	311,059	277,061	311,059	277,061	384,054
SL Green Operating Partnership
Operating Activities
Net loss	(379,228)	(37,949)	(417,585)	(24,464)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization			151,807	97,762
Equity in net loss from unconsolidated joint ventures	21,932	4,550	29,344	9,265
Distributions of cumulative earnings from unconsolidated joint ventures			409	343
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	0	131	79	131
Purchase price and other fair value adjustments			17,170	6,231
Depreciable real estate reserves and impairment			305,916	0
Loss on sale of real estate, net	26,678	64,378	28,329	65,380
Loan loss and other investment reserves, net of recoveries	0	0	6,890	0
Deferred rents receivable			(14,357)	1,075
Non-cash lease expense			10,550	12,080
Other non-cash adjustments			(2,523)	(10,406)
Changes in operating assets and liabilities:
Tenant and other receivables			(3,805)	14,767
Related party receivables			(893)	1,458
Deferred lease costs			(5,891)	(6,922)
Other assets			1,235	(2,651)
Accounts payable, accrued expenses, other liabilities and security deposits			2,697	19,767
Deferred revenue			(585)	(2,672)
Lease liability - operating leases			(4,795)	1,291
Net cash provided by operating activities			103,992	182,435
Investing Activities
Additions to land, buildings and improvements			(134,190)	(126,957)
Investments in unconsolidated joint ventures			(46,977)	(135,365)
Distributions in excess of cumulative earnings from unconsolidated joint ventures			72,823	64,976
Net proceeds from disposition of real estate/joint venture interest			97,563	353,853
Other investments			(17,779)	1,507
Origination of debt and preferred equity investments			(10,308)	(29,095)
Repayments or redemption of debt and preferred equity investments			0	6,405
Net cash (used in) provided by investing activities			(38,868)	135,324
Financing Activities
Proceeds from mortgages and other loans payable			0	184,196
Repayments of mortgages and other loans payable			(2,899)	(91,770)
Proceeds from revolving credit facility and unsecured notes			223,000	332,000
Repayments of revolving credit facility and unsecured notes			(218,000)	(592,000)
Proceeds from stock options exercised and DRSPP issuance			342	199
Repurchase of common units			0	(151,197)
Redemption of preferred units			(11,700)	(17,968)
Redemption of OP units			(5,250)	(18,334)
Distributions to noncontrolling interests in other partnerships			(763)	(3,020)
Contributions from noncontrolling interests in other partnerships			314	51,348
Distributions paid on common and preferred units			(122,533)	(140,128)
Other obligations related to secured borrowing			0	77,874
Tax withholdings related to restricted share awards			0	(3,891)
Deferred loan costs			(630)	(4,991)
Net cash used in financing activities			(138,119)	(377,682)
Net decrease in cash, cash equivalents, and restricted cash			(72,995)	(59,923)
Cash, cash equivalents, and restricted cash at beginning of year			384,054	336,984	336,984
Cash, cash equivalents, and restricted cash at end of period	311,059	277,061	311,059	277,061	384,054
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of special distribution paid primarily in units			0	160,620
Tenant improvements and capital expenditures payable			0	10,295
Fair value adjustment to noncontrolling interest in the Operating Partnership			11,198	5,085
Deconsolidation of a subsidiary			101,351	0
Contribution to consolidated joint venture interest			8,134	0
Removal of fully depreciated commercial real estate properties			7,747	3,597
Cash and cash equivalents	191,979	189,360	191,979	189,360	203,273
Restricted cash	119,080	87,701	119,080	87,701	180,781
Total cash, cash equivalents, and restricted cash	$ 311,059	$ 277,061	$ 311,059	$ 277,061	$ 384,054