Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Operating Activities
Net income	$ 480,538	$ 106,921
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	295,877	264,833
Equity in net income from unconsolidated joint ventures	(20,781)	(4,251)
Distributions of cumulative earnings from unconsolidated joint ventures	23,065	21,723
Equity in net (gain) loss on sale of interest in unconsolidated joint venture interest/real estate	(122,580)	3,937
Purchase price fair value adjustment	(71,446)	2,305
Depreciable real estate reserves	0	2,150
Gain on sale of discontinued operations	(144,242)	(14,900)
Loss on early extinguishment of debt	25,500	10,968
Deferred rents receivable	(43,736)	(44,021)
Other non-cash adjustments	(13,121)	(31,732)
Changes in operating assets and liabilities:
Restricted cash—operations	(7,124)	1,254
Tenant and other receivables	(7,336)	(3,018)
Related party receivables	(5,200)	(187)
Deferred lease costs	(17,544)	(28,502)
Other assets	(35,717)	(23,316)
Accounts payable, accrued expenses and other liabilities and security deposits	17,445	23,635
Deferred revenue and deferred land leases payable	23,608	22,731
Net cash provided by operating activities	377,206	310,530
Investing Activities
Acquisitions of real estate property	(711,437)	(58,185)
Additions to land, buildings and improvements	(282,947)	(108,849)
Escrowed cash—capital improvements/acquisition deposits	(67,868)	(246,682)
Investments in unconsolidated joint ventures	(217,187)	(120,130)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	158,809	19,795
Net proceeds from disposition of real estate/joint venture interest	357,426	218,701
Proceeds from sale of marketable securities	3,669	287
Purchase of marketable securities	(10,025)	(11,492)
Other investments	15,980	(14,874)
Origination of debt and preferred equity investments	(421,003)	(393,429)
Repayments or redemption of debt and preferred equity investments	349,320	472,317
Net cash used in investing activities	(825,263)	(242,541)
Financing Activities
Proceeds from mortgages and other loans payable	2,001,603	980,333
Repayments of mortgages and other loans payable	(1,688,466)	(1,027,201)
Proceeds from revolving credit facility, term loan and senior unsecured notes	1,136,400	844,000
Repayments of revolving credit facility, term loan and senior unsecured notes	(805,988)	(578,970)
Payment of debt extinguishment costs	(23,332)	0
Proceeds from stock options exercised and DRIP issuance	20,549	10,452
Net proceeds from sale of common stock	42,698	41,734
Net proceeds from sale of preferred stock	0	24
Redemption of preferred stock	0	(192,500)
Sale of treasury stock	0	6,089
Distributions to noncontrolling interests in other partnerships	(5,745)	(11,809)
Contributions from noncontrolling interests in other partnerships	27,933	3,781
Distributions to noncontrolling interests in the Operating Partnership	(5,482)	(2,695)
Dividends paid on common and preferred stock	(154,907)	(113,192)
Deferred loan costs and capitalized lease obligation	(50,378)	(8,921)
Net cash provided by (used in) financing activities	494,885	(48,875)
Net increase in cash and cash equivalents	46,828	19,114
Cash and cash equivalents at beginning of period	206,692	189,984
Cash and cash equivalents at end of period	253,520	209,098
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of common stock as deferred compensation	1,503	434
Issuance of units in the Operating Partnership	22,862	14,270
Redemption of units in the Operating Partnership	26,392	17,287
Issuance of preferred units of limited partnership interest in the Operating Partnership	27,565	0
Fair value adjustment to noncontrolling interest in the Operating Partnership	108,453	38,452
Derivative instruments at fair value	12,713	494
Tenant improvements and capital expenditures payable	8,456	9,855
Capital leased asset	0	9,992
Transfer to net assets held for sale	753,457	0
Transfer to liabilities related to net assets held for sale	461,891	0
Transfer of financing receivable to debt investment	19,675	0
Deferred leasing payable	13,086	2,849
Consolidation of real estate	1,316,591	90,934
Assumption of mortgage loan	0	84,642
SL Green Operating Partnership
Operating Activities
Net income	480,538	106,921
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	295,877	264,833
Equity in net income from unconsolidated joint ventures	(20,781)	(4,251)
Distributions of cumulative earnings from unconsolidated joint ventures	23,065	21,723
Equity in net (gain) loss on sale of interest in unconsolidated joint venture interest/real estate	(122,580)	3,937
Purchase price fair value adjustment	(71,446)	2,305
Depreciable real estate reserves	0	2,150
Gain on sale of discontinued operations	(144,242)	(14,900)
Loss on early extinguishment of debt	25,500	10,968
Deferred rents receivable	(43,736)	(44,021)
Other non-cash adjustments	(13,121)	(31,732)
Changes in operating assets and liabilities:
Restricted cash—operations	(7,124)	1,254
Tenant and other receivables	(7,336)	(3,018)
Related party receivables	(5,200)	(187)
Deferred lease costs	(17,544)	(28,502)
Other assets	(35,717)	(23,316)
Accounts payable, accrued expenses and other liabilities and security deposits	17,445	23,635
Deferred revenue and deferred land leases payable	23,608	22,731
Net cash provided by operating activities	377,206	310,530
Investing Activities
Acquisitions of real estate property	(711,437)	(58,185)
Additions to land, buildings and improvements	(282,947)	(108,849)
Escrowed cash—capital improvements/acquisition deposits	(67,868)	(246,682)
Investments in unconsolidated joint ventures	(217,187)	(120,130)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	158,809	19,795
Net proceeds from disposition of real estate/joint venture interest	357,426	218,701
Proceeds from sale of marketable securities	3,669	287
Purchase of marketable securities	(10,025)	(11,492)
Other investments	15,980	(14,874)
Origination of debt and preferred equity investments	(421,003)	(393,429)
Repayments or redemption of debt and preferred equity investments	349,320	472,317
Net cash used in investing activities	(825,263)	(242,541)
Financing Activities
Proceeds from mortgages and other loans payable	2,001,603	980,333
Repayments of mortgages and other loans payable	(1,688,466)	(1,027,201)
Proceeds from revolving credit facility, term loan and senior unsecured notes	1,136,400	844,000
Repayments of revolving credit facility, term loan and senior unsecured notes	(805,988)	(578,970)
Payment of debt extinguishment costs	(23,332)	0
Proceeds from stock options exercised and DRIP issuance	20,549	10,452
Net proceeds from sale of common stock	42,698	41,734
Net proceeds from sale of preferred stock	0	24
Redemption of preferred stock	0	(192,500)
Sale of treasury stock	0	6,089
Distributions to noncontrolling interests in other partnerships	(5,745)	(11,809)
Contributions from noncontrolling interests in other partnerships	27,933	3,781
Dividends paid on common and preferred stock	(160,389)	(115,887)
Deferred loan costs and capitalized lease obligation	(50,378)	(8,921)
Net cash provided by (used in) financing activities	494,885	(48,875)
Net increase in cash and cash equivalents	46,828	19,114
Cash and cash equivalents at beginning of period	206,692	189,984
Cash and cash equivalents at end of period	253,520	209,098
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of common stock as deferred compensation	1,503	434
Issuance of units in the Operating Partnership	22,862	14,270
Redemption of units in the Operating Partnership	26,392	17,287
Issuance of preferred units of limited partnership interest in the Operating Partnership	27,565	0
Derivative instruments at fair value	12,713	494
Tenant improvements and capital expenditures payable	8,456	9,855
Capital leased asset	0	9,992
Transfer to net assets held for sale	753,457	0
Transfer to liabilities related to net assets held for sale	461,891	0
Transfer of financing receivable to debt investment	19,675	0
Deferred leasing payable	13,086	2,849
Consolidation of real estate	1,316,591	90,934
Assumption of mortgage loan	$ 0	$ 84,642