Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues
Rental revenue, net	$ 291,293	$ 242,439	$ 826,877	$ 741,022
Escalation and reimbursement	43,826	42,026	120,209	114,850
Investment income	43,969	44,448	137,767	143,887
Other income	11,186	9,869	48,498	20,855
Total revenues	390,274	338,782	1,133,351	1,020,614
Expenses
Operating expenses, including $5,104 and $13,183 (2014) and $4,698 and $12,858 (2013) of related party expenses	72,111	72,784	211,118	205,921
Real estate taxes	55,548	51,529	159,702	149,857
Ground rent	8,088	7,930	24,161	23,988
Interest expense, net of interest income	82,376	78,226	236,424	232,862
Amortization of deferred financing costs	6,679	4,121	15,737	12,404
Depreciation and amortization	94,443	84,162	274,337	238,666
Transaction related costs, net of recoveries	2,383	(2,368)	6,554	717
Marketing, general and administrative	22,649	20,869	69,778	63,450
Total expenses	344,277	317,253	997,811	927,865
Income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, loss on sale of investment in marketable securities, purchase price fair value adjustment and loss on early extinguishment of debt	45,997	21,529	135,540	92,749
Equity in net income from unconsolidated joint ventures	6,034	2,939	20,781	4,251
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	16,496	(354)	122,580	(3,937)
Loss on sale of investment in marketable securities	0	0	0	(65)
Purchase price fair value adjustment	(4,000)	0	67,446	(2,305)
Loss on early extinguishment of debt	(24,475)	0	(25,500)	(18,523)
Income from continuing operations	40,052	24,114	320,847	72,170
Net income from discontinued operations	4,035	7,435	15,449	19,851
Gain on sale of discontinued operations	29,507	13,787	144,242	14,900
Net income	73,594	45,336	480,538	106,921
Net income attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership	(2,636)	(1,110)	(16,010)	(1,909)
Noncontrolling interests in other partnerships	(1,712)	(2,901)	(5,045)	(8,806)
Preferred units distribution	(820)	(562)	(1,950)	(1,692)
Net income attributable to SL Green	68,426	40,763	457,533	94,514
Preferred stock redemption costs	0	0	0	(12,160)
Perpetual preferred stock dividends	(3,738)	(3,738)	(11,214)	(18,144)
Net income attributable to SL Green common stockholders	64,688	37,025	446,319	64,210
Amounts attributable to SL Green common stockholders:
Income from continuing operations	20,312	16,772	108,710	36,518
Purchase price fair value adjustment	(3,856)	0	65,111	(2,239)
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	15,901	(344)	118,336	(3,824)
Net income from discontinued operations	3,889	7,216	14,914	19,282
Gain on sale of discontinued operations	28,442	13,381	139,248	14,473
Net income attributable to SL Green common stockholders	64,688	37,025	446,319	64,210
Basic earnings per share:
Income from continuing operations before gains (loss) on sale and discontinued operations (usd per share)	$ 0.17	$ 0.18	$ 1.82	$ 0.37
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	$ 0.17	$ 0.00	$ 1.24	$ (0.04)
Net income from discontinued operations (usd per share)	$ 0.04	$ 0.07	$ 0.16	$ 0.21
Gain on sale of discontinued operations (usd per share)	$ 0.30	$ 0.15	$ 1.46	$ 0.16
Net income attributable to SL Green common stockholders (usd per share)	$ 0.68	$ 0.40	$ 4.68	$ 0.70
Diluted earnings per share:
Income from continuing operations before gains (loss) on sale and discontinued operations (usd per share)	$ 0.17	$ 0.18	$ 1.82	$ 0.37
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	$ 0.17	$ 0.00	$ 1.23	$ (0.04)
Net income from discontinued operations (usd per share)	$ 0.04	$ 0.07	$ 0.16	$ 0.21
Gain on sale of discontinued operations (usd per share)	$ 0.30	$ 0.15	$ 1.45	$ 0.16
Net income attributable to SL Green common stockholders (usd per share)	$ 0.68	$ 0.40	$ 4.66	$ 0.70
Dividends per share (usd per share)	$ 0.50	$ 0.33	$ 1.50	$ 0.99
Basic weighted average common shares outstanding (in shares)	95,734	91,988	95,437	91,684
Diluted weighted average common shares and common share equivalents outstanding (usd per share)	99,706	95,016	99,322	94,631
SL Green Operating Partnership
Revenues
Rental revenue, net	291,293	242,439	826,877	741,022
Escalation and reimbursement	43,826	42,026	120,209	114,850
Investment income	43,969	44,448	137,767	143,887
Other income	11,186	9,869	48,498	20,855
Total revenues	390,274	338,782	1,133,351	1,020,614
Expenses
Operating expenses, including $5,104 and $13,183 (2014) and $4,698 and $12,858 (2013) of related party expenses	72,111	72,784	211,118	205,921
Real estate taxes	55,548	51,529	159,702	149,857
Ground rent	8,088	7,930	24,161	23,988
Interest expense, net of interest income	82,376	78,226	236,424	232,862
Amortization of deferred financing costs	6,679	4,121	15,737	12,404
Depreciation and amortization	94,443	84,162	274,337	238,666
Transaction related costs, net of recoveries	2,383	(2,368)	6,554	717
Marketing, general and administrative	22,649	20,869	69,778	63,450
Total expenses	344,277	317,253	997,811	927,865
Income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, loss on sale of investment in marketable securities, purchase price fair value adjustment and loss on early extinguishment of debt	45,997	21,529	135,540	92,749
Equity in net income from unconsolidated joint ventures	6,034	2,939	20,781	4,251
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	16,496	(354)	122,580	(3,937)
Loss on sale of investment in marketable securities	0	0	0	(65)
Purchase price fair value adjustment	(4,000)	0	67,446	(2,305)
Loss on early extinguishment of debt	(24,475)	0	(25,500)	(18,523)
Income from continuing operations	40,052	24,114	320,847	72,170
Net income from discontinued operations	4,035	7,435	15,449	19,851
Gain on sale of discontinued operations	29,507	13,787	144,242	14,900
Net income	73,594	45,336	480,538	106,921
Net income attributable to noncontrolling interests:
Noncontrolling interests in other partnerships	(1,712)	(2,901)	(5,045)	(8,806)
Net income attributable to SL Green	71,062	41,873	473,543	96,423
Preferred stock redemption costs	0	0	0	(12,160)
Net income attributable to SL Green common stockholders	67,324	38,135	462,329	66,119
Amounts attributable to SL Green common stockholders:
Income from continuing operations	21,286	17,267	112,612	37,610
Purchase price fair value adjustment	(4,000)	0	67,446	(2,305)
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	16,496	(354)	122,580	(3,937)
Gain on sale of discontinued operations	29,507	13,787	144,242	14,900
Net income attributable to SL Green common stockholders	67,324	38,135	462,329	66,119
Basic earnings per share:
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	$ 0.17	$ 0.00	$ 1.24	$ (0.04)
Gain on sale of discontinued operations (usd per share)	$ 0.30	$ 0.15	$ 1.46	$ 0.16
Diluted earnings per share:
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	$ 0.17	$ 0.00	$ 1.23	$ (0.04)
Gain on sale of discontinued operations (usd per share)	$ 0.30	$ 0.15	$ 1.45	$ 0.16
Noncontrolling Interest [Abstract]
Preferred unit distributions	(820)	(562)	(1,950)	(1,692)
Perpetual preferred unit distributions	(3,738)	(3,738)	(11,214)	(18,144)
Net income attributable to SLGOP common unitholders	67,324	38,135	462,329	66,119
Net income from discontinued operations	$ 4,035	$ 7,435	$ 15,449	$ 19,851
Net income from continuing operations before gains (loss) on sale and discontinued operations (in dollars per share)	$ 0.17	$ 0.18	$ 1.82	$ 0.37
Net income from discontinued operations (in dollars per share)	$ 0.04	$ 0.07	$ 0.16	$ 0.21
Net income attributable to SLGOP common stockholders (in dollars per share)	$ 0.68	$ 0.40	$ 4.68	$ 0.70
Income from continuing operations before gains (loss) on sale and discontinued operations (in dollars per share)	$ 0.17	$ 0.18	$ 1.82	$ 0.37
Net income from discontinued operations (in dollars per share)	$ 0.04	$ 0.07	$ 0.16	$ 0.21
Net income attributable to SLGOP common stockholders (in dollars per share)	$ 0.68	$ 0.40	$ 4.66	$ 0.70
Dividends per unit (usd per share)	$ 0.5	$ 0.33	$ 1.50	$ 0.99
Basic weighted average common shares outstanding (in shares)	99,319	94,780	98,860	94,389
Diluted weighted average common shares and common share equivalents outstanding (in shares)	99,706	95,016	99,322	94,631