Partners' Capital of the Operating Partnership - Additional Information (Details) - shares	9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Common Stock
Stockholders' Equity
Units outstanding (units)	64,316,000	64,302,000	64,105,000	64,881,000	65,866,000	66,474,000
SL Green Operating Partnership
Stockholders' Equity
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	3,759,073		3,781,565
SL Green Operating Partnership | Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	5.52%		5.57%
SL Green Operating Partnership | Common Stock
Stockholders' Equity
Units outstanding (units)	64,315,581
SL Green Operating Partnership | Series I Preferred Units
Stockholders' Equity
Units outstanding (units)	9,200,000
Period of restriction to redeem OP Units	1 year
Conversion of stock, shares issued	1