Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 35,161	$ (9,264)	$ 6,799	$ 11,084
Other comprehensive loss:
Decrease in unrealized value of derivative instruments, including SL Green's share of joint venture derivative instruments	(3,781)	(72,168)	(41,717)	(49,052)
Increase (decrease) in unrealized value of marketable securities	92	(228)	1,091	1,170
Other comprehensive loss	(3,689)	(72,396)	(40,626)	(47,882)
Comprehensive income (loss)	31,472	(81,660)	(33,827)	(36,798)
Net income attributable to noncontrolling interests and preferred units distributions	(6,549)	(277)	(2,879)	(2,169)
Other comprehensive loss attributable to noncontrolling interests	229	4,717	2,646	3,097
Comprehensive income (loss) attributable to SL Green	$ 25,152	$ (77,220)	$ (34,060)	$ (35,870)