Noncontrolling Interests on the Company's Consolidated Financial Statements - Schedule of Common Unit Activity (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Rollforward Analysis of Preferred Unit Activity
Contributions to consolidated joint venture interests	$ 1,823
Redemption of preferred units	(5,674)
SL Green Operating Partnership
Rollforward Analysis of Preferred Unit Activity
Contributions to consolidated joint venture interests	1,823
Redemption of preferred units	(5,674)
SL Green Operating Partnership | Preferred stock
Rollforward Analysis of Preferred Unit Activity
Balance at beginning of period	166,501	$ 177,943
Contributions to consolidated joint venture interests	0	0
Redemption of preferred units	0	(11,700)
Dividends paid on preferred units	(3,916)	(6,271)
Accrued dividends on preferred units	4,146	6,529
Balance at end of period	$ 166,731	$ 166,501