Partners' Capital of the Operating Partnership - EPS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator
Less: distributed earnings allocated to participating securities	$ (434)	$ (406)
Net income (loss) attributable to SLGOP common unitholders (numerator for basic earnings per unit)	12,707	(40,137)
Add back: dilutive effect of earnings allocated to participating securities and contingently issuable shares	(434)	0
Net (loss) income attributable to SL Green common stockholders, diluted	$ 14,042	$ (42,974)
Denominator
Common stock shares excluded from the diluted shares outstanding (shares)	135,000	1,275,225
SL Green Operating Partnership
Numerator
Net income (loss) attributable to SLGOP common unitholders (numerator for diluted earnings per unit)	$ 14,042	$ (42,068)
Less: distributed earnings allocated to participating securities	(434)	(906)
Net income (loss) attributable to SLGOP common unitholders (numerator for basic earnings per unit)	13,608	(42,974)
Add back: dilutive effect of earnings allocated to participating securities and contingently issuable shares	434	0
Net (loss) income attributable to SL Green common stockholders, diluted	$ 14,042	$ (42,974)
Denominator
Basic weighted average common units outstanding (in shares)	68,767,000	68,182,000
Stock-based compensation plans (shares)	1,328,000	0
Diluted weighted average common units outstanding (shares)	70,095,000	68,182,000
Common stock shares excluded from the diluted shares outstanding (shares)	135,000	1,275,225