Organization and Basis of Presentation - Additional Information (Details)						1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 07, 2022	Jan. 18, 2022 $ / shares shares	Jan. 10, 2022	Jan. 07, 2022 $ / shares	Dec. 02, 2021 $ / shares	Oct. 31, 2022 USD ($)	Sep. 30, 2022 USD ($) ft² building $ / shares	Sep. 30, 2021 $ / shares	Sep. 30, 2022 USD ($) ft² building $ / shares shares	Sep. 30, 2021 $ / shares	Dec. 31, 2021
Organization
Cash distribution declared, per common share (in dollars per share)							$ 0.932	$ 0.938	$ 2.797	$ 2.813
Volume weighted average share price (in dollars per share)				$ 79.71
Number of buildings | building							52		52
Area of office building (sqft) | ft²							30,122,545		30,122,545
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $							$ 670,600,000		$ 670,600,000
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $							$ 8,500,000		$ 8,500,000
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares									1
Line of Credit | Subsequent Event | Unsecured Debt
Organization
Debt instrument face amount | $						$ 400,000,000
Debt instrument renewal term						6 months
Debt fact amount, option to increase capacity | $						$ 500,000,000
Line of Credit | Subsequent Event | SOFR | Unsecured Debt
Organization
Interest rate added to base rate (as a percent)	1.40%
Shareholder Election, Cash Option Subject to Proration
Organization
Common stock, dividends, per share, cash paid (in dollars per share)		$ 0.3976
Common stock, dividends, per share, stock issued (in shares) | shares		0.0295
Shareholder Election, Stock Option
Organization
Common stock, dividends, per share, stock issued (in shares) | shares		0.0345
Managed office properties
Organization
Number of buildings | building							1		1
Area of office building (sqft) | ft²							300,000		300,000
Ordinary Dividend
Organization
Cash distribution declared, per common share (in dollars per share)					$ 0.3108
Special Dividend
Organization
Cash distribution declared, per common share (in dollars per share)					$ 2.4392
Common Stock
Organization
Reverse stock split conversion ratio			1.03060
SL Green Operating Partnership
Organization
Cash distribution declared, per common share (in dollars per share)							$ 0.932	$ 0.938	$ 2.797	$ 2.813
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)							5.52%		5.52%		5.57%
SL Green Management | SL Green Management LLC
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)									100.00%