Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (9,264)	$ (21,694)	$ 11,084	$ (439,279)
Other comprehensive (loss) income:
(Decrease) increase in unrealized value of derivative instruments, including SL Green's share of joint venture derivative instruments	(72,168)	12,799	(49,052)	23,062
(Decrease) increase in unrealized value of marketable securities	(228)	(181)	1,170	(1,625)
Other comprehensive (loss) income	(72,396)	12,618	(47,882)	21,437
Comprehensive loss	(81,660)	(9,076)	(36,798)	(417,842)
Net (income) loss attributable to noncontrolling interests and preferred units distributions	(277)	1,465	(2,169)	26,600
Other comprehensive loss (income) attributable to noncontrolling interests	4,717	(771)	3,097	(1,425)
Comprehensive loss attributable to SL Green	$ (77,220)	$ (8,382)	$ (35,870)	$ (392,667)