Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt and preferred equity investments, discount and deferred origination fees	$ 16,224	$ 22,379
Allowance for loan and lease losses, real estate	$ 1,750	$ 5,750
Preferred stock, par value (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)	82,570,000	84,739,000
Common stock, shares outstanding (in shares)	82,570,000	84,739,000
Treasury stock, shares (in shares)	1,055,000	1,055,000
Land and land interests	$ 1,860,922	$ 1,774,899
Building and improvements	5,352,144	5,268,484
Building leasehold and improvements	1,431,183	1,423,107
Right of use asset - financing leases	47,445	47,445
Accumulated depreciation	2,147,395	2,099,137
Other assets	271,467	295,679
Mortgages and other loans payable, net	2,417,161	1,961,240
Accrued interest payable	27,568	23,154
Lease liability - financing leases	44,251	43,616
Other liabilities	$ 140,899	$ 116,566
Series I Preferred Stock
Preferred stock, par value (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
Consolidated VIEs
Land and land interests	$ 219,400	$ 110,000
Building and improvements	522,900	346,700
Building leasehold and improvements	2,000	2,000
Right of use asset - financing leases	61,700	47,400
Accumulated depreciation	27,600	42,200
Other assets	99,400	112,600
Mortgages and other loans payable, net	473,200	140,800
Accrued interest payable	1,400	400
Lease liability - financing leases	57,400	43,600
Other liabilities	35,700	18,300
SL Green Operating Partnership
Debt and preferred equity investments, discount and deferred origination fees	16,224	22,379
Allowance for loan and lease losses, real estate	$ 1,750	$ 5,750
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,258,000	4,131,000
SL Green partner's capital, general partner common units outstanding (shares)	858,000	878,000
SL Green partners' capital, limited partner common units outstanding (shares)	80,657,000	82,806,000
Land and land interests	$ 1,860,922	$ 1,774,899
Building and improvements	5,352,144	5,268,484
Building leasehold and improvements	1,431,183	1,423,107
Right of use asset - financing leases	47,445	47,445
Accumulated depreciation	2,147,395	2,099,137
Other assets	271,467	295,679
Mortgages and other loans payable, net	2,417,161	1,961,240
Accrued interest payable	27,568	23,154
Lease liability - financing leases	44,251	43,616
Other liabilities	$ 140,899	$ 116,566
SL Green Operating Partnership | Series I Preferred Stock
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
SL Green Operating Partnership | Consolidated VIEs
Land and land interests	$ 219,400	$ 110,000
Building and improvements	522,900	346,700
Building leasehold and improvements	2,000	2,000
Right of use asset - financing leases	61,700	47,400
Accumulated depreciation	27,600	42,200
Other assets	99,400	112,600
Mortgages and other loans payable, net	473,200	140,800
Accrued interest payable	1,400	400
Lease liability - financing leases	57,400	43,600
Other liabilities	$ 35,700	$ 18,300