Organization and Basis of Presentation - Additional Information (Details) ft² in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) ft² building shares	Dec. 31, 2023
Organization
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $	$ 352.3
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $	$ 4.8
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares	1
Managed Office Properties
Organization
Number of buildings | building	1
Approximate Square Feet | ft²	0.4
Retail Site
Organization
Number of buildings | building	1
Service Corporation
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	95.00%
Operating Partnership | SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	6.38%	5.75%
SL Green Management | SL Green Management LLC
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	100.00%