Organization and Basis of Presentation - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) ft² building	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Organization
Number of Buildings | building	52
Approximate Square Feet | ft²	29,716,041
Debt and preferred equity investments including investments held by unconsolidated joint ventures	$ 623,280	$ 1,088,723	$ 1,076,542
Managed office properties
Organization
Number of Buildings | building	1
Approximate Square Feet | ft²	300,000
Debt and preferred equity investments including investments held by unconsolidated joint ventures	$ 623,300
Debt and preferred equity investments and other financing receivables included in other balance sheet items	$ 8,500
Service Corporation
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	95.00%
SLG Management LLC | SL Green Management
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	100.00%
Operating Partnership | SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	5.39%	5.57%