Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Commercial real estate properties, at cost:
Land and land interests	$ 3,466,587	$ 3,032,526
Building and improvements	8,843,315	7,884,663
Building leasehold and improvements	1,390,004	1,366,281
Properties under capital lease	27,445	50,310
Total commercial real estate properties, at cost	13,727,351	12,333,780
Less: accumulated depreciation	(1,769,428)	(1,646,240)
Total commercial real estate properties, net	11,957,923	10,687,540
Assets held for sale	339,809	0
Cash and cash equivalents	308,103	206,692
Restricted cash	157,225	142,051
Investment in marketable securities	39,912	32,049
Tenant and other receivables, net of allowance of $20,026 and $17,325 in 2014 and 2013, respectively	51,844	60,393
Related party receivables	8,915	8,530
Deferred rents receivable, net of allowance of $27,616 and $30,333 in 2014 and 2013, respectively	354,388	386,508
Debt and preferred equity investments, net of discounts and deferred origination fees of $14,633 and $18,593 in 2014 and 2013, respectively, and allowance of $1,000 in 2013	1,547,808	1,304,839
Investments in unconsolidated joint ventures	971,926	1,113,218
Deferred costs, net	300,043	267,058
Other assets	679,840	750,123
Total assets	16,717,736	14,959,001
Liabilities
Mortgages and other loans payable	5,939,176	4,860,578
Revolving credit facility	0	220,000
Term loan and senior unsecured notes	2,127,206	1,739,330
Accrued interest payable and other liabilities	128,730	114,622
Accounts payable and accrued expenses	164,215	145,889
Deferred revenue	223,394	263,261
Capitalized lease obligations	20,635	47,671
Deferred land leases payable	1,044	22,185
Dividend and distributions payable	53,193	52,255
Security deposits	65,166	61,308
Liabilities related to assets held for sale	193,375	0
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	9,016,134	7,627,099
Commitments and contingencies	0	0
Noncontrolling interests in the Operating Partnership	379,805	265,476
Preferred Units	49,550	49,550
Equity
Common stock, $0.01 par value, 160,000 shares authorized and 99,188 and 98,563 issued and outstanding at June 30, 2014 and December 31, 2013, respectively (including 3,601 and 3,570 shares held in Treasury at June 30, 2014 and December 31, 2013, respectively)	993	986
Additional paid-in-capital	5,085,965	5,015,904
Treasury stock at cost	(320,152)	(317,356)
Accumulated other comprehensive loss	(6,196)	(15,211)
Retained earnings	1,797,580	1,619,150
Total SL Green stockholders' equity	6,780,122	6,525,405
Noncontrolling interests in other partnerships	492,125	491,471
Total equity	7,272,247	7,016,876
Total liabilities and equity	16,717,736	14,959,001
Series I Preferred Stock
Equity
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at both June 30, 2014 and December 31, 2013	221,932	221,932
SL Green Operating Partnership
Commercial real estate properties, at cost:
Land and land interests	3,466,587	3,032,526
Building and improvements	8,843,315	7,884,663
Building leasehold and improvements	1,390,004	1,366,281
Properties under capital lease	27,445	50,310
Total commercial real estate properties, at cost	13,727,351	12,333,780
Less: accumulated depreciation	(1,769,428)	(1,646,240)
Total commercial real estate properties, net	11,957,923	10,687,540
Assets held for sale	339,809	0
Cash and cash equivalents	308,103	206,692
Restricted cash	157,225	142,051
Investment in marketable securities	39,912	32,049
Tenant and other receivables, net of allowance of $20,026 and $17,325 in 2014 and 2013, respectively	51,844	60,393
Related party receivables	8,915	8,530
Deferred rents receivable, net of allowance of $27,616 and $30,333 in 2014 and 2013, respectively	354,388	386,508
Debt and preferred equity investments, net of discounts and deferred origination fees of $14,633 and $18,593 in 2014 and 2013, respectively, and allowance of $1,000 in 2013	1,547,808	1,304,839
Investments in unconsolidated joint ventures	971,926	1,113,218
Deferred costs, net	300,043	267,058
Other assets	679,840	750,123
Total assets	16,717,736	14,959,001
Liabilities
Mortgages and other loans payable	5,939,176	4,860,578
Revolving credit facility	0	220,000
Term loan and senior unsecured notes	2,127,206	1,739,330
Accrued interest payable and other liabilities	128,730	114,622
Accounts payable and accrued expenses	164,215	145,889
Deferred revenue	223,394	263,261
Capitalized lease obligations	20,635	47,671
Deferred land leases payable	1,044	22,185
Dividend and distributions payable	53,193	52,255
Security deposits	65,166	61,308
Liabilities related to assets held for sale	193,375	0
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	9,016,134	7,627,099
Commitments and contingencies	0	0
Preferred Units	49,550	49,550
Equity
Accumulated other comprehensive loss	(6,413)	(15,662)
Total liabilities and equity	16,717,736	14,959,001
SLGOP partners' capital:
SL Green partners' capital 991 and 979 general partner common units and 94,596 and 94,014 limited partner common units outstanding at June 30, 2014 and December 31, 2013, respectively)	6,860,374	6,506,747
Limited partner interests in SLGOP (3,500 and 2,902 limited partner common units outstanding at June 30, 2014 and December 31, 2013, respectively)	84,034	77,864
Total SLGOP partners' capital	7,159,927	6,790,881
Noncontrolling interests in other partnerships	492,125	491,471
Total capital	7,652,052	7,282,352
SL Green Operating Partnership | Series I Preferred Stock
SLGOP partners' capital:
Series I Preferred Units, $25.00 liquidation preference, 9,200 outstanding at both June 30, 2014 and December 31, 2013	221,932	221,932
Total capital	$ 221,932	$ 221,932