Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Commercial real estate properties, at cost:
Land and land interests	$ 2,866,048	$ 2,886,099
Building and improvements	7,393,930	7,389,766
Building leasehold and improvements	1,352,953	1,346,748
Properties under capital lease	50,332	40,340
Total commercial real estate properties, at cost	11,663,263	11,662,953
Less: accumulated depreciation	(1,502,694)	(1,393,323)
Total commercial real estate properties, net	10,160,569	10,269,630
Assets held for sale	207,665	4,901
Cash and cash equivalents	198,969	189,984
Restricted cash	130,483	136,071
Investment in marketable securities	26,266	21,429
Tenant and other receivables, net of allowance of $20,466 and $21,652 in 2013 and 2012, respectively	51,646	48,544
Related party receivables	6,845	7,531
Deferred rents receivable, net of allowance of $29,821 and $29,580 in 2013 and 2012, respectively	360,954	340,747
Debt and preferred equity investments, net of discounts and deferred origination fees of $27,107 and $22,341 and allowance of $7,000 both in 2013 and 2012, respectively	1,227,421	1,348,434
Investments in unconsolidated joint ventures	1,085,793	1,032,243
Deferred costs, net	246,058	261,145
Other assets	699,256	718,326
Total assets	14,401,925	14,378,985
Liabilities
Mortgages and other loans payable	4,835,231	4,615,464
Revolving credit facility	40,000	70,000
Term loan and senior unsecured notes	1,735,205	1,734,956
Accrued interest payable and other liabilities	72,415	73,769
Accounts payable and accrued expenses	138,029	159,598
Deferred revenue	296,930	312,995
Capitalized lease obligations	47,240	37,518
Deferred land leases payable	19,948	20,897
Dividend and distributions payable	34,740	37,839
Security deposits	53,604	46,253
Liabilities related to assets held for sale	11,894	136
Junior subordinate deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	7,385,236	7,209,425
Commitments and contingencies
Noncontrolling interest in the Operating Partnership	243,925	212,907
SL Green stockholders' equity:
Common stock, $0.01 par value, 160,000 shares authorized and 95,376 and 94,896 issued and outstanding at June 30, 2013 and December 31, 2012, respectively (including 3,563 and 3,646 shares held in Treasury at June 30, 2013 and December 31, 2012, respectively)	955	950
Additional paid-in-capital	4,716,012	4,667,900
Treasury stock at cost	(316,768)	(322,858)
Accumulated other comprehensive loss	(18,622)	(29,587)
Retained earnings	1,631,287	1,701,092
Total SL Green stockholders' equity	6,234,796	6,419,802
Noncontrolling interests in other partnerships	488,418	487,301
Total equity	6,723,214	6,907,103
Total liabilities and equity	14,401,925	14,378,985
Series G Preferred Units
Liabilities
Preferred Units	47,550	47,550
Series H Preferred Units
Liabilities
Preferred Units	2,000	2,000
Series C Preferred Stock
SL Green stockholders' equity:
Preferred stock		180,340
Series I Preferred Stock
SL Green stockholders' equity:
Preferred stock	$ 221,932	$ 221,965