Partners' Capital of the Operating Partnership - Additional Information (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Series I Preferred Units
Stockholders' Equity
Preferred stock, shares outstanding (in shares)	9,200,000	9,200,000
Common Stock
Stockholders' Equity
Units, outstanding (in units)	64,726,000	64,380,000	64,105,000	66,474,000
SL Green Operating Partnership
Stockholders' Equity
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	3,949,448	3,670,343
SL Green Operating Partnership | Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	5.75%	5.39%
SL Green Operating Partnership | Series I Preferred Units
Stockholders' Equity
Common units redemption, period of restriction	1 year
Conversion of stock, shares issued (in shares)	1
SL Green Operating Partnership | Common Stock
Stockholders' Equity
Units, outstanding (in units)	64,726,253
Excess shares issued (shares)	64,726,253