Consolidated Statements of Capital - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest	$ (9,216)		$ (29,817)
DRSPP proceeds	52,308	$ 525	525
Measurement adjustment for redeemable noncontrolling interest	(107,631)	(15,486)	39,974
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	26,848	35,573	32,034
Proceeds from issuance of common stock	386,790
Repurchases of common units	0		(151,197)
Contributions to consolidated joint venture interests	6,656	15,066	52,164
Consolidation of partially owned entity	59,452
Cash distributions to noncontrolling interests	$ (11,053)	$ (2,777)	$ (4,699)
Common Stock
Increase (Decrease) in Partner's Capital
DRSPP proceeds (in units)	729	17	11
DRSPP proceeds	$ 7
Conversion of common units (in units)	124
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in units)	455	329	274
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	$ 4	$ 4	$ 4
Proceeds from issuance of common stock (in shares)	5,063
Proceeds from issuance of common stock	$ 51
Repurchases of common units (in units)			(1,971)
Repurchases of common units	$ (11)		$ (20)
Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest	(5,086)		(75)
Contributions to consolidated joint venture interests	6,656	15,066	52,164
Consolidation of partially owned entity	59,452
Cash distributions to noncontrolling interests	(11,053)	(2,777)	(4,699)
SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning balance	3,855,925	4,646,922	4,778,253
Net income (loss)	21,082	(569,127)	(76,952)
Acquisition of subsidiary interest from noncontrolling interest	(9,216)		(29,817)
Other comprehensive income (loss)	719	(32,127)	96,362
Perpetual preferred unit dividends	(14,950)	(14,950)	(14,950)
DRSPP proceeds	52,308	525	525
Measurement adjustment for redeemable noncontrolling interest	(107,631)	(15,486)	39,974
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	26,848	35,573	32,034
Proceeds from issuance of common stock	386,790
Repurchases of common units			(151,197)
Contributions to consolidated joint venture interests	6,656	15,066	52,164
Consolidation of partially owned entity	59,452
Cash distributions to noncontrolling interests	(11,053)	(2,777)	(4,699)
Issuance of special distribution paid in units			160,620
Cash distributions declared	(196,979)	(207,694)	(235,395)
Ending balance	4,069,951	3,855,925	4,646,922
SL Green Operating Partnership | Preferred Units | Series I Preferred Units
Increase (Decrease) in Partner's Capital
Beginning balance	221,932	221,932	221,932
Ending balance	221,932	221,932	221,932
SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning balance	$ 3,546,906	$ 4,313,497	$ 4,589,702
Beginning balance (units)	64,726	64,380	64,105
Net income (loss)	$ 22,010	$ (564,559)	$ (78,074)
Acquisition of subsidiary interest from noncontrolling interest	(4,130)		(29,742)
Perpetual preferred unit dividends	$ (14,950)	$ (14,950)	$ (14,950)
DRSPP proceeds (in units)	729	17	11
DRSPP proceeds	$ 52,308	$ 525	$ 525
Conversion of common units (in units)	124
Measurement adjustment for redeemable noncontrolling interest	$ (107,631)	$ (15,486)	$ 39,974
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in units)	455	329	274
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	$ 26,848	$ 35,573	$ 32,034
Proceeds from issuance of common stock (in shares)	5,063
Proceeds from issuance of common stock	$ 386,790
Repurchases of common units (in units)			(1,971)
Repurchases of common units			$ (151,197)
Issuance of special distribution paid in units (in shares)			1,961
Issuance of special distribution paid in units			$ 160,620
Cash distributions declared	(196,979)	(207,694)	(235,395)
Ending balance	$ 3,711,172	$ 3,546,906	$ 4,313,497
Ending balance (units)	71,097	64,726	64,380
SL Green Operating Partnership | Accumulated Other Comprehensive Income
Increase (Decrease) in Partner's Capital
Beginning balance	$ 17,477	$ 49,604	$ (46,758)
Other comprehensive income (loss)	719	(32,127)	96,362
Ending balance	18,196	17,477	49,604
SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning balance	69,610	61,889	13,377
Net income (loss)	(928)	(4,568)	1,122
Acquisition of subsidiary interest from noncontrolling interest	(5,086)		(75)
Contributions to consolidated joint venture interests	6,656	15,066	52,164
Consolidation of partially owned entity	59,452
Cash distributions to noncontrolling interests	(11,053)	(2,777)	(4,699)
Ending balance	$ 118,651	$ 69,610	$ 61,889