Partners' Capital of the Operating Partnership - EPS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator
Less: distributed earnings allocated to participating securities	$ (435)	$ (408)	$ (1,309)	$ (1,225)
Net loss attributable to SLGOP common unitholders (numerator for basic earnings per unit)	(13,714)	(24,375)	(3,607)	(425,117)
Net Income (Loss) Available to Common Stockholders, Diluted	$ (13,714)	$ (25,949)	$ (3,607)	$ (452,610)
Denominator
Common stock shares excluded from the diluted shares outstanding (shares)	5,345,430	1,402,771	5,155,662	1,380,364
SL Green Operating Partnership
Numerator
Net loss attributable to SLGOP common unitholders	$ (14,193)	$ (25,541)	$ (2,464)	$ (451,385)
Less: distributed earnings allocated to participating securities	(1,147)	(408)	(3,415)	(1,225)
Net loss attributable to SLGOP common unitholders (numerator for basic earnings per unit)	(15,340)	(25,949)	(5,879)	(452,610)
Net Income (Loss) Available to Common Stockholders, Diluted	$ (15,340)	$ (25,949)	$ (5,879)	$ (452,610)
Denominator
Basic weighted average common units outstanding (in shares)	67,999,000	68,296,000	68,092,000	68,274,000
Diluted weighted average common units outstanding (shares)	67,999,000	68,296,000	68,092,000	68,274,000
Common stock shares excluded from the diluted shares outstanding (shares)	1,734,283	1,402,771	1,418,306	1,380,364