Noncontrolling Interests on the Company's Consolidated Financial Statements - Additional Information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Distributions | $	$ (2,777)	$ (4,699)	$ (6,631)
Acquisition of subsidiary interest from noncontrolling interest | $		(29,817)
Net loss | $	(37,465)	(5,794)	25,457
Accumulated other comprehensive income allocation | $	$ (1,960)	5,827	1,042
Series B Preferred Stock
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Preferred units, issued (in shares)	0
SL Green Operating Partnership
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $	$ 269,993	344,252
Distributions | $	(14,779)	(16,272)
Issuance of common units | $	25,365	22,855
Acquisition of subsidiary interest from noncontrolling interest | $	(18,589)	(40,901)
Net loss | $	(37,465)	(5,794)
Accumulated other comprehensive income allocation | $	(1,960)	5,827
Fair value adjustment | $	15,486	(39,974)
Balance at end of period | $	$ 238,051	$ 269,993	344,252
SL Green Operating Partnership
Organization
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)	3,949,448	3,670,343
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Distributions | $	$ (2,777)	$ (4,699)	(6,631)
Acquisition of subsidiary interest from noncontrolling interest | $		(29,817)
Accumulated other comprehensive income allocation | $	$ (1,960)	$ 5,827	$ 1,042
SL Green Operating Partnership | Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	5.75%	5.39%
SL Green Operating Partnership | Series A Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	5.00%
Preferred Units, shares authorized (in shares)	109,161
Number of preferred units issued (in shares)	109,161
Preferred units, shares outstanding (in shares)	109,161
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 50.0000
Liquidation preference of preferred units (in dollars per share) | $ / shares	1,000
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 0
Number of company common stock issued on conversion of Series B preferred units	6.71348
SL Green Operating Partnership | Series F Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	7.00%
Preferred Units, shares authorized (in shares)	60
Number of preferred units issued (in shares)	60
Preferred units, shares outstanding (in shares)	60
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 70.0000
Liquidation preference of preferred units (in dollars per share) | $ / shares	1,000
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 29.12
SL Green Operating Partnership | Series K Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	3.50%
Preferred Units, shares authorized (in shares)	700,000
Number of preferred units issued (in shares)	563,954
Preferred units, shares outstanding (in shares)	341,677
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	25.00
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 134.67
SL Green Operating Partnership | Series L Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	4.00%
Preferred Units, shares authorized (in shares)	500,000
Number of preferred units issued (in shares)	378,634
Preferred units, shares outstanding (in shares)	372,634
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 1.0000
Liquidation preference of preferred units (in dollars per share) | $ / shares	25.00
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 0
SL Green Operating Partnership | Series R Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	3.50%
Preferred Units, shares authorized (in shares)	400,000
Number of preferred units issued (in shares)	400,000
Preferred units, shares outstanding (in shares)	400,000
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	25.00
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 154.89
SL Green Operating Partnership | Series S Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	4.00%
Preferred Units, shares authorized (in shares)	1,077,280
Number of preferred units issued (in shares)	1,077,280
Preferred units, shares outstanding (in shares)	1,077,280
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 1.0000
Liquidation preference of preferred units (in dollars per share) | $ / shares	25.00
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 0
SL Green Operating Partnership | Series V Preferred Stock
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Stated Distribution Rate	5.00%
Preferred Units, shares authorized (in shares)	40,000
Number of preferred units issued (in shares)	40,000
Preferred units, shares outstanding (in shares)	40,000
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 1.2500
Liquidation preference of preferred units (in dollars per share) | $ / shares	25.00
Conversion Price Per Unit (in dollars per share) | $ / shares	$ 0
SL Green Operating Partnership | Series W
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Preferred Units, shares authorized (in shares)	1
Number of preferred units issued (in shares)	1
Preferred units, shares outstanding (in shares)	1
Preferred stock, dividend, multiplier per common unit distribution	1,350
SL Green Operating Partnership | Series B Preferred Stock
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Convertible preferred stock, shares issued upon conversion (in shares)	1