Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 31, 2012
Debt and preferred equity investments, net of discounts and deferred origination fees	$ 5,057	$ 11,232
Allowance for loan and lease losses	$ 6,630	$ 13,213	$ 1,750	$ 5,750
Preferred stock, par (in dollars per share)	$ 0.01
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	65,132,000	67,470,000
Common stock, shares outstanding (in shares)	65,132,000	67,470,000
Treasury stock, shares (in shares)	1,027,000	996,000
Land	$ 1,350,701	$ 1,315,832
Building and improvements	3,671,402	4,168,193
Building leasehold and improvements	1,645,081	1,448,134
Right of use asset - financing leases	0	55,711
Accumulated depreciation	1,896,199	1,956,077
Other assets	262,841	448,213
Real estate debt	1,394,386	1,979,972
Accrued interest payable	12,698	14,825
Lease liabilities	102,914	152,521
Other liabilities	195,390	302,798
SL Green Operating Partnership
Debt and preferred equity investments, net of discounts and deferred origination fees	5,057	11,232
Allowance for loan and lease losses	$ 6,630	$ 13,213
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	3,782,000	3,939,000
SL Green partner's capital, general partner common units outstanding (shares)	677,000	703,000
SL Green partners' capital, limited partner common units outstanding (shares)	63,428,000	65,771,000
Land	$ 1,350,701	$ 1,315,832
Building and improvements	3,671,402	4,168,193
Building leasehold and improvements	1,645,081	1,448,134
Right of use asset - financing leases	0	55,711
Accumulated depreciation	1,896,199	1,956,077
Other assets	262,841	448,213
Real estate debt	1,394,386	1,979,972
Accrued interest payable	12,698	14,825
Lease liabilities	102,914	152,521
Other liabilities	$ 195,390	$ 302,798
Series I Preferred Stock
Preferred stock, par (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, shares issued (in shares)	9,200,000	9,200,000
Preferred stock, shares outstanding (in shares)	9,200,000	9,200,000			9,200,000
Series I Preferred Stock | SL Green Operating Partnership
Preferred units, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred units, shares issued (in shares)	9,200,000	9,200,000
Preferred units, shares outstanding (in shares)	9,200,000	9,200,000