Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (21,694)	$ 12,211	$ (439,279)	$ (12,253)
Other comprehensive income:
Increase in unrealized value of derivative instruments, including SL Green's share of joint venture derivative instruments	12,799	50,488	23,062	111,378
(Decrease) increase in unrealized value of marketable securities	(181)	1,605	(1,625)	(642)
Other comprehensive income	12,618	52,093	21,437	110,736
Comprehensive (loss) income	(9,076)	64,304	(417,842)	98,483
Net loss (income) attributable to noncontrolling interests and preferred units distributions	1,465	(1,096)	26,600	(5,282)
Other comprehensive income attributable to noncontrolling interests	(771)	(3,114)	(1,425)	(6,404)
Comprehensive (loss) income attributable to SL Green	$ (8,382)	$ 60,094	$ (392,667)	$ 86,797