SL Green Realty (SLG) 10-K 21 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Document Information [Line Items]
Entity Registrant Name	SL GREEN REALTY CORP
Entity Central Index Key	1,040,971
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		100,579,714
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 10,000,000,000
SL Green Operating Partnership
Document Information [Line Items]
Entity Registrant Name	SL GREEN OPERATING PARTNERSHIP, LP.
Entity Central Index Key	1,492,869
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,497,224
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Commercial real estate properties, at cost:
Land and land interests	$ 3,309,710	$ 4,779,159
Building and improvements	7,948,852	10,423,739
Building leasehold and improvements	1,437,325	1,431,259
Properties under capital lease	47,445	47,445
Total commercial real estate properties, at cost	12,743,332	16,681,602
Less: accumulated depreciation	(2,264,694)	(2,060,706)
Total commercial real estate properties, net	10,478,638	14,620,896
Assets held for sale	0	34,981
Cash and cash equivalents	279,443	255,399
Restricted cash	90,524	233,578
Investments in marketable securities	85,110	45,138
Tenant and other receivables, net of allowance of $16,592 and $17,618 in 2016 and 2015, respectively	53,772	63,491
Related party receivables	15,856	10,650
Deferred rents receivable, net of allowance of $25,203 and $21,730 in 2016 and 2015, respectively	442,179	498,776
Debt and preferred equity investments, net of discounts and deferred origination fees of $16,705 and $18,759 in 2016 and 2015, respectively	1,640,412	1,670,020
Investments in unconsolidated joint ventures	1,890,186	1,203,858
Deferred costs, net	267,600	239,920
Other assets	614,067	850,939
Total assets	15,857,787	19,727,646
Liabilities
Mortgages and other loans payable, net	4,073,830	6,881,920
Revolving credit facility, net	0	985,055
Unsecured term loan, net	1,179,521	929,514
Unsecured notes, net	1,128,315	1,378,964
Accrued interest payable	36,052	42,406
Other liabilities	206,238	168,477
Accounts payable and accrued expenses	190,583	196,213
Deferred revenue	217,955	399,102
Capital lease obligations	42,132	41,360
Deferred land leases payable	2,583	1,783
Dividend and distributions payable	87,271	79,790
Security deposits	66,504	68,023
Liabilities related to assets held for sale	0	29,000
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	7,330,984	11,301,607
Commitments and contingencies
Noncontrolling interests in Operating Partnership	473,882	424,206
Preferred units	302,010	282,516
Equity
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at both December 31, 2016 and 2015	221,932	221,932
Common stock, $0.01 par value, 160,000 shares authorized and 101,617 and 100,063 issued and outstanding at December 31, 2016 and 2015, respectively (including 1,055 and 87 shares held in treasury at December 31, 2016 and 2015, respectively)	1,017	1,001
Additional paid-in-capital	5,624,545	5,439,735
Treasury stock at cost	(124,049)	(10,000)
Accumulated other comprehensive income (loss)	22,137	(8,749)
Retained earnings	1,578,893	1,643,546
Total SL Green stockholders' equity	7,324,475	7,287,465
Noncontrolling interests in other partnerships	426,436	431,852
Total equity	7,750,911	7,719,317
SL Green stockholders equity:
Total liabilities and equity/capital	15,857,787	19,727,646
SL Green Operating Partnership
Commercial real estate properties, at cost:
Land and land interests	3,309,710	4,779,159
Building and improvements	7,948,852	10,423,739
Building leasehold and improvements	1,437,325	1,431,259
Properties under capital lease	47,445	47,445
Total commercial real estate properties, at cost	12,743,332	16,681,602
Less: accumulated depreciation	(2,264,694)	(2,060,706)
Total commercial real estate properties, net	10,478,638	14,620,896
Assets held for sale	0	34,981
Cash and cash equivalents	279,443	255,399
Restricted cash	90,524	233,578
Investments in marketable securities	85,110	45,138
Tenant and other receivables, net of allowance of $16,592 and $17,618 in 2016 and 2015, respectively	53,772	63,491
Related party receivables	15,856	10,650
Deferred rents receivable, net of allowance of $25,203 and $21,730 in 2016 and 2015, respectively	442,179	498,776
Debt and preferred equity investments, net of discounts and deferred origination fees of $16,705 and $18,759 in 2016 and 2015, respectively	1,640,412	1,670,020
Investments in unconsolidated joint ventures	1,890,186	1,203,858
Deferred costs, net	267,600	239,920
Other assets	614,067	850,939
Total assets	15,857,787	19,727,646
Liabilities
Mortgages and other loans payable, net	4,073,830	6,881,920
Revolving credit facility, net	0	985,055
Unsecured term loan, net	1,179,521	929,514
Unsecured notes, net	1,128,315	1,378,964
Accrued interest payable	36,052	42,406
Other liabilities	206,238	168,477
Accounts payable and accrued expenses	190,583	196,213
Deferred revenue	217,955	399,102
Capital lease obligations	42,132	41,360
Deferred land leases payable	2,583	1,783
Dividend and distributions payable	87,271	79,790
Security deposits	66,504	68,023
Liabilities related to assets held for sale	0	29,000
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	7,330,984	11,301,607
Commitments and contingencies
Preferred units	302,010	282,516
Equity
Accumulated other comprehensive income (loss)	22,137	(8,749)
SL Green stockholders equity:
Limited partner interests in SLGOP (4,364 and 3,746 limited partner common units outstanding at December 31, 2016 and 2015, respectively)	473,882	424,206
Series I Preferred Units, $25.00 liquidation preference, 9,200 issued and outstanding at both December 31, 2016 and 2015	221,932	221,932
SL Green partners' capital (1,049 and 1,035 general partner common units, and 99,513 and 98,941 limited partner common units outstanding at December 31, 2016 and 2015, respectively)	7,080,406	7,074,282
Total SLGOP partners' capital	7,324,475	7,287,465
Noncontrolling interests in other partnerships	426,436	431,852
Total capital	7,750,911	7,719,317
Total liabilities and equity/capital	$ 15,857,787	$ 19,727,646

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tenant and other receivables, allowance	$ 16,592	$ 17,618
Deferred rents receivable, allowance	25,203	21,730
Debt and preferred equity investments, discount and deferred origination fees	$ 16,705	$ 18,759
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred stock, shares issued	9,200,000	9,200,000
Preferred stock, shares outstanding	9,200,000	9,200,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	160,000,000	160,000,000
Common stock, shares issued	101,617,000	100,063,000
Common stock, shares outstanding	101,617,000	100,063,000
Treasury stock, shares	1,055,000	87,000
SL Green Operating Partnership
Tenant and other receivables, allowance	$ 16,592	$ 17,618
Deferred rents receivable, allowance	25,203	21,730
Debt and preferred equity investments, discount and deferred origination fees	$ 16,705	$ 18,759
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,364,000	3,746,000
Preferred units, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred units, shares issued	9,200,000	9,200,000
Preferred units, shares outstanding	9,200,000	9,200,000
SL Green partner's capital, general partner common units outstanding (shares)	1,049,000	1,035,000
SL Green partners' capital, limited partner common units outstanding (shares)	99,513,000	98,941,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Rental revenue, net	$ 1,323,767	$ 1,245,981	$ 1,121,066
Escalation and reimbursement	196,858	178,512	164,376
Investment income	213,008	181,128	178,815
Other income	130,348	57,208	55,721
Total revenues	1,863,981	1,662,829	1,519,978
Expenses
Operating expenses, including $21,890 in 2016, $20,071 in 2015, and $19,308 in 2014 of related party expenses	312,859	301,624	282,283
Real estate taxes	248,388	232,702	217,843
Ground rent	33,261	32,834	32,307
Interest expense, net of interest income	321,199	323,870	317,400
Amortization of deferred financing costs	24,564	27,348	22,377
Depreciation and amortization	821,041	560,887	371,610
Transaction related costs	7,528	11,430	8,707
Marketing, general and administrative	99,759	94,873	92,488
Total expenses	1,868,599	1,585,568	1,345,015
(Loss) income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, (loss) gain on sale of marketable securities and loss on early extinguishment of debt	(4,618)	77,261	174,963
Equity in net income from unconsolidated joint ventures	11,874	13,028	26,537
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	44,009	15,844	123,253
Purchase price fair value adjustment	0	40,078	67,446
Gain on sale of real estate, net	238,116	175,974	0
Depreciable real estate reserves	(10,387)	(19,226)	0
(Loss) gain on sale of investment in marketable securities	(83)	0	3,895
Loss on early extinguishment of debt	0	(49)	(32,365)
Income from continuing operations	278,911	302,910	363,729
Net income from discontinued operations	0	427	19,075
Gain on sale of discontinued operations	0	14,122	163,059
Net income	278,911	317,459	545,863
Net income attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership	(10,136)	(10,565)	(18,467)
Net income attributable to noncontrolling interests in other partnerships	(7,644)	(15,843)	(6,590)
Preferred unit distributions	(11,235)	(6,967)	(2,750)
Net income (loss) attributable to SL Green/SLGOP	249,896	284,084	518,056
Preferred stock/unit redemption costs	0	0	0
Perpetual preferred stock dividends	(14,950)	(14,952)	(14,952)
Amounts attributable to SL Green common stockholders:
(Loss) income from continuing operations before purchase price fair value adjustment, gains on sale and discontinued operations	(25,552)	50,502	143,466
Purchase price fair value adjustment	0	38,563	65,059
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	42,189	15,245	118,891
Net income from discontinued operations	0	411	18,400
Gain on sale of discontinued operations	0	13,588	157,288
Gain on sale of real estate	228,266	169,322	0
Depreciable real estate reserves	(9,957)	(18,499)	0
Net income attributable to SL Green common stockholders	$ 234,946	$ 269,132	$ 503,104
Basic earnings per share:
Income from continuing operations before purchase price fair value adjustment, gains on sale and discontinued operations (usd per share)	$ (0.26)	$ 0.51	$ 1.50
Purchase price fair value adjustment (usd per share)	0	0.39	0.68
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0.42	0.15	1.24
Net income from discontinued operations (usd per share)	0	0	0.19
Gain on sale of discontinued operations (usd per share)	0	0.14	1.64
Gain on sale of real estate (in dollars per share)	2.29	1.71	0
Depreciable real estate reserves (in dollars per share)	(0.10)	(0.19)	0
Net income attributable to SL Green common stockholders (usd per share)	2.35	2.71	5.25
Diluted earnings per share:
Income from continuing operations before purchase price fair value adjustment, gains on sale and discontinued operations (usd per share)	(0.25)	0.51	1.52
Purchase price fair value adjustment (usd per share)	0	0.39	0.65
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0.42	0.15	1.24
Net income from discontinued operations (usd per share)	0	0	0.19
Gain on sale of discontinued operations (usd per share)	0	0.14	1.63
Gain on sale of real estate (in dollars per share)	2.27	1.70	0
Depreciable real estate reserves (in dollars per share)	(0.10)	(0.19)	0
Net income attributable to SL Green common stockholders (usd per share)	$ 2.34	$ 2.70	$ 5.23
Basic weighted average common shares outstanding (in shares)	100,185	99,345	95,774
Diluted weighted average common shares and common share equivalents outstanding (in shares)	104,881	103,734	99,696
SL Green Operating Partnership
Revenues
Rental revenue, net	$ 1,323,767	$ 1,245,981	$ 1,121,066
Escalation and reimbursement	196,858	178,512	164,376
Investment income	213,008	181,128	178,815
Other income	130,348	57,208	55,721
Total revenues	1,863,981	1,662,829	1,519,978
Expenses
Operating expenses, including $21,890 in 2016, $20,071 in 2015, and $19,308 in 2014 of related party expenses	312,859	301,624	282,283
Real estate taxes	248,388	232,702	217,843
Ground rent	33,261	32,834	32,307
Interest expense, net of interest income	321,199	323,870	317,400
Amortization of deferred financing costs	24,564	27,348	22,377
Depreciation and amortization	821,041	560,887	371,610
Transaction related costs	7,528	11,430	8,707
Marketing, general and administrative	99,759	94,873	92,488
Total expenses	1,868,599	1,585,568	1,345,015
(Loss) income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, (loss) gain on sale of marketable securities and loss on early extinguishment of debt	(4,618)	77,261	174,963
Equity in net income from unconsolidated joint ventures	11,874	13,028	26,537
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	44,009	15,844	123,253
Purchase price fair value adjustment	0	40,078	67,446
Gain on sale of real estate, net	238,116	175,974	0
Depreciable real estate reserves	(10,387)	(19,226)	0
(Loss) gain on sale of investment in marketable securities	(83)	0	3,895
Loss on early extinguishment of debt	0	(49)	(32,365)
Income from continuing operations	278,911	302,910	363,729
Net income from discontinued operations	0	427	19,075
Gain on sale of discontinued operations	0	14,122	163,059
Net income	278,911	317,459	545,863
Net income attributable to noncontrolling interests:
Net income attributable to noncontrolling interests in other partnerships	(7,644)	(15,843)	(6,590)
Preferred unit distributions	(11,235)	(6,967)	(2,750)
Net income (loss) attributable to SL Green/SLGOP	260,032	294,649	536,523
Preferred stock/unit redemption costs	0	0	0
Perpetual preferred stock dividends	(14,950)	(14,952)	(14,952)
Net income attributable to SLGOP common unitholders	245,082	279,697	521,571
Amounts attributable to SL Green common stockholders:
(Loss) income from continuing operations before purchase price fair value adjustment, gains on sale and discontinued operations	(26,656)	52,478	148,738
Purchase price fair value adjustment	0	40,078	67,446
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	44,009	15,844	123,253
Net income from discontinued operations	0	427	19,075
Gain on sale of discontinued operations	0	14,122	163,059
Gain on sale of real estate	238,116	175,974	0
Depreciable real estate reserves	$ (10,387)	$ (19,226)	$ 0
Basic earnings per share:
Income from continuing operations before gains on sale and discontinued operations (usd per share)	$ (0.26)	$ 0.51	$ 1.50
Purchase price fair value adjustment (usd per share)	0	0.39	0.68
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0.42	0.15	1.24
Net income from discontinued operations (usd per share)	0	0	0.19
Gain on sale of discontinued operations (usd per share)	0	0.14	1.64
Gain on sale of real estate (in dollars per share)	2.29	1.71	0
Depreciable real estate reserves (in dollars per share)	(0.10)	(0.19)	0
Net income attributable to SLGOP common unitholders (usd per share)	2.35	2.71	5.25
Diluted earnings per share:
Income from continuing operations before gains on sale and discontinued operations (usd per share)	(0.25)	0.51	1.52
Purchase price fair value adjustment (usd per share)	0	0.39	0.65
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0.42	0.15	1.24
Net income from discontinued operations (usd per share)	0	0	0.19
Gain on sale of discontinued operations (usd per share)	0	0.14	1.63
Gain on sale of real estate (in dollars per share)	2.27	1.70	0
Depreciable real estate reserves (in dollars per share)	(0.10)	(0.19)	0
Net income attributable to SLGOP common unitholders (usd per share)	$ 2.34	$ 2.70	$ 5.23
Basic weighted average common units outstanding (in shares)	104,508	103,244	99,288
Diluted weighted average common units and common unit equivalents outstanding (in shares)	104,881	103,734	99,696

Consolidated Statements of Ope5

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses, paid to related parties	$ 21,890	$ 20,071	$ 19,308
SL Green Operating Partnership
Operating expenses, paid to related parties	$ 21,890	$ 20,071	$ 19,308

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 278,911	$ 317,459	$ 545,863
Other comprehensive income (loss):
Change in net unrealized (loss) gain on derivative instruments, including SL Green's/SLGOP's share of joint venture net unrealized (loss) gain on derivative instruments	28,508	(1,229)	10,643
Change in unrealized gain (loss) on marketable securities	3,677	(607)	(2,237)
Other comprehensive income (loss)	32,185	(1,836)	8,406
Comprehensive income	311,096	315,623	554,269
Net income attributable to noncontrolling interests and preferred units distributions	(29,015)	(33,375)	(27,807)
Net income attributable to noncontrolling interests	7,644	15,843	6,590
Other comprehensive income (loss) attributable to noncontrolling interests	(1,299)	67	(175)
Comprehensive income attributable to SL Green/SLGOP	280,782	282,315	526,287
SL Green Operating Partnership
Net income	278,911	317,459	545,863
Other comprehensive income (loss):
Change in net unrealized (loss) gain on derivative instruments, including SL Green's/SLGOP's share of joint venture net unrealized (loss) gain on derivative instruments	28,508	(1,229)	10,643
Change in unrealized gain (loss) on marketable securities	3,677	(607)	(2,237)
Other comprehensive income (loss)	32,185	(1,836)	8,406
Comprehensive income	311,096	315,623	554,269
Net income attributable to noncontrolling interests	7,644	15,843	6,590
Other comprehensive income (loss) attributable to noncontrolling interests	(1,299)	67	(175)
Comprehensive income attributable to SL Green/SLGOP	$ 302,153	$ 299,847	$ 547,504

Consolidated Statement of Equit

Consolidated Statement of Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series C Preferred StockPreferred Stock	Series I Preferred StockPreferred Stock
Beginning Balance at Dec. 31, 2013	$ 7,016,876	$ 950	$ 4,841,800	$ 0	$ (15,211)	$ 1,475,934	$ 491,471	$ 0	$ 221,932
Beginning Balance (in shares) at Dec. 31, 2013		94,993,000
Increase (Decrease) in Stockholders' Equity
Net income	524,646					518,056	6,590
Other comprehensive loss	8,231				8,231
Preferred dividends	(14,952)					(14,952)
DRSPP proceeds	64		64
Conversion of units of the Operating Partnership to common stock (in shares)		315,000
Conversion of units of the Operating Partnership to common stock	31,653	$ 3	31,650
Reallocation of noncontrolling interest in the Operating Partnership	168,439					168,439
Deferred compensation plan and stock award, net (in shares)		15,000
Deferred compensation plan and stock award, net	(1,514)		(15)			(1,499)
Amortization of deferred compensation plan	$ 29,749		29,749
Issuance of common stock (in shares)	1,626,999	1,654,000
Issuance of common stock	$ 185,321	$ 17	185,304
Proceeds from stock options exercised (in shares)		348,000
Proceeds from stock options exercised	25,211	$ 4	25,207
Contributions to consolidated joint venture interests	30,800						30,800
Cash distributions to noncontrolling interests	(7,019)						(7,019)
Cash distributions declared ($2.52, $2.10, and $1.49 per common share, respectively, none of which represented a return of capital for federal income tax purposes)	(201,411)					(201,411)
Ending Balance at Dec. 31, 2014	7,459,216	$ 974	5,113,759	0	(6,980)	1,607,689	521,842	0	221,932
Ending Balance (in shares) at Dec. 31, 2014		97,325,000
Increase (Decrease) in Stockholders' Equity
Net income	299,927					284,084	15,843
Acquisition of subsidiary interest from noncontrolling interest	(20,650)		(9,566)				(11,084)
Other comprehensive loss	(1,769)				(1,769)
Preferred dividends	(14,952)					(14,952)
DRSPP (in shares)		776,000
DRSPP proceeds	99,555	$ 8	99,547
Conversion of units of the Operating Partnership to common stock (in shares)		483,000
Conversion of units of the Operating Partnership to common stock	55,697	$ 5	55,692
Reallocation of noncontrolling interest in the Operating Partnership	20,915					20,915
Reallocation of capital account relating to sale	(10,143)						(10,143)
Deferred compensation plan and stock award, net (in shares)		168,000
Deferred compensation plan and stock award, net	(2,982)	$ 2	243			(3,227)
Amortization of deferred compensation plan	26,721		26,721
Issuance of common stock (in shares)		1,007,000
Issuance of common stock	126,989	$ 10	136,979	(10,000)
Proceeds from stock options exercised (in shares)		217,000
Proceeds from stock options exercised	16,362	$ 2	16,360
Contributions to consolidated joint venture interests	35,178						35,178
Cash distributions to noncontrolling interests	(119,784)						(119,784)
Cash distributions declared ($2.52, $2.10, and $1.49 per common share, respectively, none of which represented a return of capital for federal income tax purposes)	(250,963)					(250,963)
Ending Balance at Dec. 31, 2015	7,719,317	$ 1,001	5,439,735	(10,000)	(8,749)	1,643,546	431,852	0	221,932
Ending Balance (in shares) at Dec. 31, 2015		99,976,000
Increase (Decrease) in Stockholders' Equity
Net income	257,540					249,896	7,644
Other comprehensive loss	30,886				30,886
Preferred dividends	(14,950)					(14,950)
DRSPP (in shares)		2,000
DRSPP proceeds	277		277
Conversion of units of the Operating Partnership to common stock (in shares)		295,000
Conversion of units of the Operating Partnership to common stock	31,806	$ 3	31,803
Reallocation of noncontrolling interest in the Operating Partnership	4,222					4,222
Deferred compensation plan and stock award, net (in shares)		96,000
Deferred compensation plan and stock award, net	(1,988)	$ 1	(1,989)
Amortization of deferred compensation plan	25,890		25,890
Issuance of common stock	(40)	$ 10	113,999	(114,049)
Proceeds from stock options exercised (in shares)		193,000
Proceeds from stock options exercised	14,832	$ 2	14,830
Contributions to consolidated joint venture interests	2,359						2,359
Cash distributions to noncontrolling interests	(15,419)						(15,419)
Cash distributions declared ($2.52, $2.10, and $1.49 per common share, respectively, none of which represented a return of capital for federal income tax purposes)	(295,377)					(295,377)
Ending Balance at Dec. 31, 2016	$ 7,750,911	$ 1,017	$ 5,624,545	$ (124,049)	$ 22,137	$ 1,578,893	$ 426,436	$ 0	$ 221,932
Ending Balance (in shares) at Dec. 31, 2016		100,562,000

Consolidated Statement of Equi8

Consolidated Statement of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Cash distribution declared, per common share (in dollars per share)	$ 2.94	$ 2.52	$ 2.10

Consolidated Statement of Capit

Consolidated Statement of Capital - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest						$ (20,650)
Conversion of common units					$ 31,806	55,697	$ 31,653
DRSPP proceeds					277	99,555	64
Reallocation of capital account relating to sale						(10,143)
Reallocation of noncontrolling interests in the operating partnership					4,222	20,915	168,439
Deferred compensation plan and stock award, net					(1,988)	(2,982)	(1,514)
Amortization of deferred compensation plan					25,890	26,721	$ 29,749
Contributions - net proceeds from common stock offering (in units)							1,626,999
Cash distributions to noncontrolling interests					(15,419)	(119,784)	$ (7,019)
Common Stock
Increase (Decrease) in Partner's Capital
Conversion of common units					$ 3	$ 5	$ 3
DRSPP (in units)					2,000	776,000
DRSPP proceeds						$ 8
Deferred compensation plan and stock award, net, as adjusted (in units)					96,000	168,000	15,000
Deferred compensation plan and stock award, net					$ 1	$ 2
Contributions - net proceeds from common stock offering (in units)						1,007,000	1,654,000
Contributions - proceeds from stock options exercised (in units)					193,000	217,000	348,000
Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest						$ (11,084)
Reallocation of capital account relating to sale						(10,143)
Cash distributions to noncontrolling interests					$ (15,419)	(119,784)	$ (7,019)
SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance		$ 7,719,317		$ 7,459,216	7,719,317	7,459,216	7,016,876
Net income					257,540	299,927	524,646
Acquisition of subsidiary interest from noncontrolling interest						(20,650)
Other comprehensive (loss)					30,886	(1,769)	8,231
Preferred distributions	$ (4,252)	(4,622)	$ (5,277)	(6,878)	(14,950)	(14,952)	(14,952)
Conversion of common units					31,806	55,697	31,653
DRSPP proceeds					277	99,555	64
Reallocation of capital account relating to sale						(10,143)
Reallocation of noncontrolling interests in the operating partnership					4,222	20,915	168,439
Deferred compensation plan and stock award, net					(1,988)	(2,982)	(1,514)
Amortization of deferred compensation plan					25,890	26,721	29,749
Issuance of stock					(40)
Contribution to consolidated joint venture interests					2,359	35,178	30,800
Contributions - net proceeds from common stock offering						126,989	185,321
Contributions - proceeds from stock options exercised					14,832	16,362	25,211
Cash distributions to noncontrolling interests					(15,419)	(119,784)	(7,019)
Cash distributions declared ($2.52, $2.10, and $1.49 per common unit, respectively, none of which represented a return of capital for federal income tax purposes)					(295,377)	(250,963)	(201,411)
Ending Balance	7,750,911		7,719,317		7,750,911	7,719,317	7,459,216
SL Green Operating Partnership | Preferred Units | Series C Preferred Stock
Increase (Decrease) in Partner's Capital
Beginning Balance		0		0	0	0	0
Ending Balance	0		0		0	0	0
SL Green Operating Partnership | Preferred Units | Series I Preferred Stock
Increase (Decrease) in Partner's Capital
Beginning Balance		221,932		221,932	221,932	221,932	221,932
Ending Balance	221,932		221,932		221,932	221,932	221,932
SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning Balance		$ 7,074,282		$ 6,722,422	$ 7,074,282	$ 6,722,422	$ 6,318,684
Beginning Balance (units)		99,976,000		97,325,000	99,976,000	97,325,000	94,993,000
Net income					$ 249,896	$ 284,084	$ 518,056
Acquisition of subsidiary interest from noncontrolling interest						(9,566)
Preferred distributions					$ (14,950)	$ (14,952)	$ (14,952)
Conversion of common units (in units)					295,000	483,000	315,000
Conversion of common units					$ 31,806	$ 55,697	$ 31,653
DRSPP (in units)						776,000
DRSPP proceeds					277	$ 99,555	64
Reallocation of noncontrolling interests in the operating partnership					$ 4,222	$ 20,915	$ 168,439
Deferred compensation plan and stock award, net, as adjusted (in units)					96,000	168,000	15,000
Deferred compensation plan and stock award, net					$ (1,988)	$ (2,982)	$ (1,514)
Amortization of deferred compensation plan					25,890	$ 26,721	$ 29,749
Issuance of stock					$ (40)
Contributions - net proceeds from common stock offering (in units)						1,007,000	1,654,000
Contributions - net proceeds from common stock offering						$ 126,989	$ 185,321
Contributions - proceeds from stock options exercised (in units)					193,000	217,000	348,000
Contributions - proceeds from stock options exercised					$ 14,832	$ 16,362	$ 25,211
Cash distributions declared ($2.52, $2.10, and $1.49 per common unit, respectively, none of which represented a return of capital for federal income tax purposes)					(295,377)	(250,963)	(201,411)
Ending Balance	$ 7,080,406		$ 7,074,282		$ 7,080,406	$ 7,074,282	$ 6,722,422
Ending Balance (units)	100,562,000		99,976,000		100,562,000	99,976,000	97,325,000
SL Green Operating Partnership | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partner's Capital
Beginning Balance		$ (8,749)		$ (6,980)	$ (8,749)	$ (6,980)	$ (15,211)
Other comprehensive (loss)					30,886	(1,769)	8,231
Ending Balance	$ 22,137		$ (8,749)		22,137	(8,749)	(6,980)
SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning Balance		$ 431,852		$ 521,842	431,852	521,842	491,471
Net income					7,644	15,843	6,590
Acquisition of subsidiary interest from noncontrolling interest						(11,084)
Reallocation of capital account relating to sale						(10,143)
Contribution to consolidated joint venture interests					2,359	35,178	30,800
Cash distributions to noncontrolling interests					(15,419)	(119,784)	(7,019)
Ending Balance	$ 426,436		$ 431,852		$ 426,436	$ 431,852	$ 521,842

Consolidated Statement of Cap10

Consolidated Statement of Capital (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash distribution declared, per common share (in dollars per share)	$ 2.94	$ 2.52	$ 2.10
SL Green Operating Partnership
Cash distribution declared, per common share (in dollars per share)	$ 2.94	$ 2.52	$ 2.1

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income	$ 278,911		$ 317,459	$ 545,863
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	845,605		588,238	400,001
Equity in net income from unconsolidated joint ventures	(11,874)		(13,028)	(26,537)
Distributions of cumulative earnings from unconsolidated joint ventures	24,337		40,759	28,859
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	(44,009)		(15,844)	(123,253)
Purchase price fair value adjustment	0		(40,078)	(71,446)
Depreciable real estate reserves	10,387		19,226	0
Gain on sale of real estate	(238,116)		(175,974)	0
Gain on sale of discontinued operations	0		(14,122)	(163,059)
Gain on sale of investments in marketable securities	83		0	(3,895)
Loss on early extinguishment of debt	0		49	32,365
Deferred rents receivable	26,716		(136,924)	(56,362)
Other non-cash adjustments	(150,913)	[1]	(20,671)	(28,559)
Changes in operating assets and liabilities:
Restricted cash—operations	(10,811)		11,289	861
Tenant and other receivables	4,780		(6,405)	1,978
Related party receivables	(5,183)		1,278	(3,673)
Deferred lease costs	(70,707)		(61,005)	(53,333)
Other assets	9,899		18,501	9,340
Accounts payable, accrued expenses and other liabilities and security deposits	(35,628)		8,634	(7,796)
Deferred revenue and land leases payable	1,237		5,102	9,027
Net cash provided by operating activities	634,714		526,484	490,381
Investing Activities
Acquisitions of real estate property	(37,760)		(2,653,311)	(1,039,530)
Additions to land, buildings and improvements	(411,950)		(406,442)	(369,887)
Escrowed cash—capital improvements/acquisition deposits/deferred purchase price	92,374		(101,000)	(8,461)
Investments in unconsolidated joint ventures	(84,456)		(161,712)	(382,010)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	196,211		98,639	236,181
Proceeds from disposition of real estate/joint venture interest	2,469,719		1,216,785	820,599
Proceeds from sale of marketable securities	6,965		1,426	8,248
Purchases of marketable securities	(43,341)		(7,769)	(14,364)
Other investments	7,704		(15,806)	(7,448)
Origination of debt and preferred equity investments	(977,413)		(756,939)	(617,090)
Repayments or redemption of debt and preferred equity investments	904,517		520,218	576,927
Net cash provided by (used in) investing activities	2,122,570		(2,265,911)	(796,835)
Financing Activities
Proceeds from mortgages and other loans payable	408,293		1,849,293	2,151,603
Repayments of mortgages and other loans payable	(1,822,303)		(781,236)	(2,201,999)
Proceeds from revolving credit facility and senior unsecured notes	1,325,300		2,515,000	1,908,000
Repayments of revolving credit facility and senior unsecured notes	(2,334,604)		(1,706,007)	(1,386,588)
Payments of debt extinguishment costs	0		0	(50,150)
Proceeds from stock options exercised and DRIP issuance	15,109		115,917	25,275
Proceeds from sale of common stock	0		124,761	185,321
Redemption of preferred stock	(3,299)		(200)	(2,000)
Distributions to noncontrolling interests in other partnerships	(15,419)		(119,784)	(7,019)
Contributions from noncontrolling interests in other partnerships	2,359		12,674	30,675
Distributions to noncontrolling interests in the Operating Partnership	(12,671)		(9,710)	(7,849)
Dividends/Distributions paid on common and preferred stock/units	(314,079)		(257,378)	(206,974)
Other obligations related to mortgage loan participations	59,150		25,000	0
Deferred loan costs and capitalized lease obligation	(41,076)		(54,913)	(57,124)
Net cash (used in) provided by financing activities	(2,733,240)		1,713,417	381,171
Net increase (decrease) in cash and cash equivalents	24,044		(26,010)	74,717
Cash and cash equivalents at beginning of year	255,399		281,409	206,692
Cash and cash equivalents at end of period	279,443		255,399	281,409
Supplemental Cash Flow Information [Abstract]
Interest paid	344,295		345,110	348,230
Income taxes paid	2,009		3,882	4,056
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of units in the operating partnership	78,495		30,506	56,469
Redemption of units in the operating partnership	31,806		55,697	31,653
Derivative instruments at fair value	31,826		1,816	11,230
Exchange of debt investment for equity in joint venture	68,581		10,151	0
Transfer of restricted cash to operating cash and cash equivalents as a result of sale	0		21,578	0
Acquisition of subsidiary interest from noncontrolling interest	0		20,630	0
Tenant improvements and capital expenditures payable	15,972		7,755	9,408
Mortgage assigned to joint venture	0		0	150,000
Fair value adjustment to noncontrolling interest in operating partnership	4,222		20,915	168,439
Assumption of mortgage loan	0		112,795	16,000
Investment in Joint Venture	0		0	88,957
Capital lease assets	0		20,000	0
Reclass of development costs from other assets to real estate	0		47,519	0
Deconsolidation of a subsidiary	1,226,425		27,435	112,095
Transfer of assets to assets held for sale	2,048,376		34,981	462,430
Transfer of liabilities related to assets held for sale	1,677,528		29,000	266,873
Transfer of financing receivable to debt investment	0		0	19,675
Deferred leasing payable	1,556		7,832	8,667
Consolidation of real estate investment	0		158,566	1,316,591
Removal of fully depreciated commercial real estate properties	31,474		241,910	0
Issuance of SLG's common stock to a consolidated joint venture	114,049		10,000	0
Contribution to consolidated joint venture by noncontrolling interest	0		22,504	0
SL Green Operating Partnership
Operating Activities
Net income	278,911		317,459	545,863
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	845,605		588,238	400,001
Equity in net income from unconsolidated joint ventures	(11,874)		(13,028)	(26,537)
Distributions of cumulative earnings from unconsolidated joint ventures	24,337		40,759	28,859
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	(44,009)		(15,844)	(123,253)
Purchase price fair value adjustment	0		(40,078)	(71,446)
Depreciable real estate reserves	10,387		19,226	0
Gain on sale of real estate	(238,116)		(175,974)	0
Gain on sale of discontinued operations	0		(14,122)	(163,059)
Gain on sale of investments in marketable securities	83		0	(3,895)
Loss on early extinguishment of debt	0		49	32,365
Deferred rents receivable	26,716		(136,924)	(56,362)
Other non-cash adjustments	(150,913)	[1]	(20,671)	(28,559)
Changes in operating assets and liabilities:
Restricted cash—operations	(10,811)		11,289	861
Tenant and other receivables	4,780		(6,405)	1,978
Related party receivables	(5,183)		1,278	(3,673)
Deferred lease costs	(70,707)		(61,005)	(53,333)
Other assets	9,899		18,501	9,340
Accounts payable, accrued expenses and other liabilities and security deposits	(35,628)		8,634	(7,796)
Deferred revenue and land leases payable	1,237		5,102	9,027
Net cash provided by operating activities	634,714		526,484	490,381
Investing Activities
Acquisitions of real estate property	(37,760)		(2,653,311)	(1,039,530)
Additions to land, buildings and improvements	(411,950)		(406,442)	(369,887)
Escrowed cash—capital improvements/acquisition deposits/deferred purchase price	92,374		(101,000)	(8,461)
Investments in unconsolidated joint ventures	(84,456)		(161,712)	(382,010)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	196,211		98,639	236,181
Proceeds from disposition of real estate/joint venture interest	2,469,719		1,216,785	820,599
Proceeds from sale of marketable securities	6,965		1,426	8,248
Purchases of marketable securities	(43,341)		(7,769)	(14,364)
Other investments	7,704		(15,806)	(7,448)
Origination of debt and preferred equity investments	(977,413)		(756,939)	(617,090)
Repayments or redemption of debt and preferred equity investments	904,517		520,218	576,927
Net cash provided by (used in) investing activities	2,122,570		(2,265,911)	(796,835)
Financing Activities
Proceeds from mortgages and other loans payable	408,293		1,849,293	2,151,603
Repayments of mortgages and other loans payable	(1,822,303)		(781,236)	(2,201,999)
Proceeds from revolving credit facility and senior unsecured notes	1,325,300		2,515,000	1,908,000
Repayments of revolving credit facility and senior unsecured notes	(2,334,604)		(1,706,007)	(1,386,588)
Payments of debt extinguishment costs	0		0	(50,150)
Proceeds from stock options exercised and DRIP issuance	15,109		115,917	25,275
Proceeds from sale of common stock	0		124,761	185,321
Redemption of preferred stock	(3,299)		(200)	(2,000)
Distributions to noncontrolling interests in other partnerships	(15,419)		(119,784)	(7,019)
Contributions from noncontrolling interests in other partnerships	2,359		12,674	30,675
Dividends/Distributions paid on common and preferred stock/units	(326,750)		(267,088)	(214,823)
Other obligations related to mortgage loan participations	59,150		25,000	0
Deferred loan costs and capitalized lease obligation	(41,076)		(54,913)	(57,124)
Net cash (used in) provided by financing activities	(2,733,240)		1,713,417	381,171
Net increase (decrease) in cash and cash equivalents	24,044		(26,010)	74,717
Cash and cash equivalents at beginning of year	255,399		281,409	206,692
Cash and cash equivalents at end of period	279,443		255,399	281,409
Supplemental Cash Flow Information [Abstract]
Interest paid	344,295		345,110	348,230
Income taxes paid	2,009		3,882	4,056
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of units in the operating partnership	78,495		30,506	56,469
Redemption of units in the operating partnership	31,806		55,697	31,653
Derivative instruments at fair value	31,826		1,816	11,230
Exchange of debt investment for equity in joint venture	68,581		10,151	0
Transfer of restricted cash to operating cash and cash equivalents as a result of sale	0		21,578	0
Acquisition of subsidiary interest from noncontrolling interest	0		20,630	0
Tenant improvements and capital expenditures payable	15,972		7,755	9,408
Mortgage assigned to joint venture	0		0	150,000
Fair value adjustment to noncontrolling interest in operating partnership	4,222		20,915	168,439
Assumption of mortgage loan	0		112,795	16,000
Investment in Joint Venture	0		0	88,957
Capital lease assets	0		20,000	0
Reclass of development costs from other assets to real estate	0		47,519	0
Deconsolidation of a subsidiary	1,226,425		27,435	112,095
Transfer of assets to assets held for sale	2,048,376		34,981	462,430
Transfer of liabilities related to assets held for sale	1,677,528		29,000	266,873
Transfer of financing receivable to debt investment	0		0	19,675
Deferred leasing payable	1,556		7,832	8,667
Consolidation of real estate investment	0		158,566	1,316,591
Removal of fully depreciated commercial real estate properties	31,474		241,910	0
Issuance of SLG's common stock to a consolidated joint venture	114,049		10,000	0
Contribution to consolidated joint venture by noncontrolling interest	0		22,504	0
Common Stock
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units relating to the real estate acquisition	0		2,228	0
Common Stock | SL Green Operating Partnership
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units relating to the real estate acquisition	0		2,228	0
Preferred Units
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units relating to the real estate acquisition	22,793		211,601	27,565
Preferred Units | SL Green Operating Partnership
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units relating to the real estate acquisition	$ 22,793		$ 211,601	$ 27,565
[1]	Included in Other non-cash adjustments is $172.4 million for the year ended December 31, 2016 for the amortization of the below-market lease at 388-390 Greenwich Street as a result of the tenant exercising their option to purchase the property and entering into an agreement to accelerate the sale.

Consolidated Statements of Ca12

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly distributions declared, per share/unit (usd per share/unit)	$ 0.775	$ 0.72	$ 0.60
SL Green Operating Partnership
Quarterly distributions declared, per share/unit (usd per share/unit)	$ 0.775	$ 0.72	$ 0.6
388-390 Greenwich Street
Amortization of below market leases	$ 172.4
388-390 Greenwich Street | SL Green Operating Partnership
Amortization of below market leases	$ 172.4

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation SL Green Realty Corp., which is referred to as the Company or SL Green, a Maryland corporation, and SL Green Operating Partnership, L.P., which is referred to as SLGOP or the Operating Partnership, a Delaware limited partnership, were formed in June 1997 for the purpose of combining the commercial real estate business of S.L. Green Properties, Inc. and its affiliated partnerships and entities. The Operating Partnership received a contribution of interest in the real estate properties, as well as 95% of the economic interest in the management, leasing and construction companies which are referred to as the Service Corporation. All of the management, leasing and construction services that are provided to the properties that are wholly-owned by us and that are provided to certain joint ventures are conducted through SL Green Management LLC which is 100% owned by the Operating Partnership. The Company has qualified, and expects to qualify in the current fiscal year, as a real estate investment trust, or REIT, under the Internal Revenue Code of 1986, as amended, or the Code, and operates as a self-administered, self-managed REIT. A REIT is a legal entity that holds real estate interests and, through payments of dividends to stockholders, is permitted to minimize the payment of Federal income taxes at the corporate level. Unless the context requires otherwise, all references to "we," "our" and "us" means the Company and all entities owned or controlled by the Company, including the Operating Partnership. Substantially all of our assets are held by, and all of our operations are conducted through, the Operating Partnership. The Company is the sole managing general partner of the Operating Partnership. As of December 31, 2016 , noncontrolling investors held, in the aggregate, a 4.16% limited partnership interest in the Operating Partnership. We refer to these interests as the noncontrolling interests in the Operating Partnership. The Operating Partnership is considered a variable interest entity, or VIE, in which we are the primary beneficiary. See Note 11, "Noncontrolling Interests on the Company's Consolidated Financial Statements". Reckson Associates Realty Corp., or Reckson, and Reckson Operating Partnership, L.P., or ROP, are wholly-owned subsidiaries of SL Green Realty Corp. As of December 31, 2016 , we owned the following interests in properties in the New York Metropolitan area, primarily in midtown Manhattan. Our investments in the New York Metropolitan area also include investments in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties: Consolidated Unconsolidated Total Location Property Type Number of Properties Approximate Square Feet (unaudited) Number of Properties Approximate Square Feet (unaudited) Number of Properties Approximate Square Feet (unaudited) Weighted Average Occupancy (1) (unaudited) Commercial: Manhattan Office 24 16,054,606 7 6,558,139 31 22,612,745 94.9 % Retail 10 (2) 418,093 9 347,970 19 766,063 85.6 % Development/Redevelopment 3 42,635 3 770,514 6 813,149 52.3 % Fee Interest 1 176,530 1 26,926 2 203,456 100.0 % 38 16,691,864 20 7,703,549 58 24,395,413 93.2 % Suburban Office 25 4,113,800 2 640,000 27 4,753,800 82.6 % Retail 1 52,000 — — 1 52,000 100.0 % Development/Redevelopment 1 1,000 1 — 2 1,000 100.0 % 27 4,166,800 3 640,000 30 4,806,800 82.8 % Total commercial properties 65 20,858,664 23 8,343,549 88 29,202,213 91.5 % Residential: Manhattan Residential 3 (2) 472,105 18 3,247,764 21 3,719,869 83.8 % Suburban Residential — — — — — — — % Total residential properties 3 472,105 18 3,247,764 21 3,719,869 83.8 % Total portfolio 68 21,330,769 41 11,591,313 109 32,922,082 90.6 % ____________________________________________________________________ (1) The weighted average occupancy for commercial properties represents the total occupied square feet divided by total square footage at acquisition. The weighted average occupancy for residential properties represents the total occupied units divided by total available units. (2) As of December 31, 2016 , we owned a building that was comprised of approximately 270,132 square feet (unaudited) of retail space and approximately 222,855 square feet (unaudited) of residential space. For the purpose of this report, we have included the building in the number of retail properties we own. However, we have included only the retail square footage in the retail approximate square footage, and have listed the balance of the square footage as residential square footage. As of December 31, 2016 , we also managed an approximately 336,000 square foot (unaudited) office building owned by a third party and held debt and preferred equity investments with a book value of $2.0 billion , including $0.3 billion of debt and preferred equity investments and other financing receivables that are included in balance sheet line items other than the Debt and Preferred Equity Investments line item. Partnership Agreement In accordance with the partnership agreement of the Operating Partnership, or the Operating Partnership Agreement, we allocate all distributions and profits and losses in proportion to the percentage of ownership interests of the respective partners. As the managing general partner of the Operating Partnership, we are required to take such reasonable efforts, as determined by us in our sole discretion, to cause the Operating Partnership to distribute sufficient amounts to enable the payment of sufficient dividends by us to minimize any Federal income or excise tax at the Company level. Under the Operating Partnership Agreement, each limited partner has the right to redeem units of limited partnership interests for cash, or if we so elect, shares of SL Green's common stock on a one-for- one basis. Subsequent Events In January 2017, we sold a 27.6% interest in One Vanderbilt Avenue to the National Pension Service of Korea ("NPS") and a 1.4% interest to Hines Interest LP ("Hines"). NPS and Hines have committed aggregate equity to the project totaling no less than $525 million . SL Green Realty Corp. and Hines will co-develop the building. In January 2017, we entered into an agreement to sell 520 White Plains Road in Tarrytown, NY for a gross sale price of $21.0 million . We expect to record a $11.1 million charge in connection with the sale, which will be included in depreciable real estate reserves. The transaction is expected to close during the second quarter of 2017. At December 31, 2016, we determined that the held for sale criteria was not met for this property as it was not probable that the sale of the asset would be completed within one year.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Principles of Consolidation The consolidated financial statements include our accounts and those of our subsidiaries, which are wholly-owned or controlled by us. Entities which we do not control through our voting interest and entities which are variable interest entities, but where we are not the primary beneficiary, are accounted for under the equity method. See Note 5, "Debt and Preferred Equity Investments" and Note 6, "Investments in Unconsolidated Joint Ventures." All significant intercompany balances and transactions have been eliminated. We consolidate a variable interest entity, or VIE, in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. Included in commercial real estate properties on our consolidated balance sheets as of December 31, 2016 and 2015 are $ 1.7 billion and $200.7 million , respectively, related to our consolidated VIEs, excluding the Operating Partnership. Included in mortgages and other loans payable on our consolidated balance sheets as of December 31, 2016 and 2015 are $621.8 million and $101.1 million , respectively, related to our consolidated VIEs, excluding the Operating Partnership. As of December 31, 2015, assets held for sale and liabilities related to assets held for sale on the consolidated balance sheets did not include amounts related to consolidated VIEs. A noncontrolling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to us. Noncontrolling interests are required to be presented as a separate component of equity in the consolidated balance sheet and the presentation of net income is modified to present earnings and other comprehensive income attributed to controlling and noncontrolling interests. We assess the accounting treatment for each joint venture and debt and preferred equity investment. This assessment includes a review of each joint venture or limited liability company agreement to determine the rights provided to each party and whether those rights are protective or participating. For all VIEs, we review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity's economic performance. In situations where we and our partner approve, among other things, the annual budget, receive a detailed monthly reporting package, meet on a quarterly basis to review the results of the joint venture, review and approve the joint venture's tax return before filing, and approve all leases that cover more than a nominal amount of space relative to the total rentable space at each property, we do not consolidate the joint venture as we consider these to be substantive participation rights that result in shared power of the activities that most significantly impact the performance of the joint venture. Our joint venture agreements typically contain certain protective rights such as requiring partner approval to sell, finance or refinance the property and the payment of capital expenditures and operating expenditures outside of the approved budget or operating plan. Investment in Commercial Real Estate Properties Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. A property to be disposed of is reported at the lower of its carrying value or its estimated fair value, less its cost to sell. Once an asset is held for sale, depreciation expense is no longer recorded. The Company adopted ASU 2014-08 effective January 1, 2015 which raised the threshold for disposals to qualify as discontinued operations to include only dispositions that represent a strategic shift in an entity’s operations. The guidance was applied prospectively for new disposals. As a result, the Company classified 388 Greenwich as held for sale as of March 31, 2016, 500 West Putnam as held for sale as of June 30, 2016, and 400 East 57th Street as held for sale as of September 30, 2016 and included the results of operations in continuing operations for all periods presented. The Company classified 242-252 Bedford Avenue in Brooklyn, New York as held for sale as of December 31, 2015, 570 & 574 Fifth Avenue and 140-150 Grand Street in White Plains, New York as held for sale as of September 30, 2015 and 131-137 Spring Street and 120 West 45th Street as of June 30, 2015 and included the results of operations in continuing operations for all periods presented. Discontinued operations included the results of operations of real estate assets sold or held for sale prior to January 1, 2015. This included 180 Maiden Lane, which was held for sale at December 31, 2014 and sold in January 2015, and 2 Herald Square, 985-987 Third Avenue and 673 First Avenue, which were sold during 2014. See Note 4, "Properties Held for Sale and Dispositions." Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows: Category Term Building (fee ownership) 40 years Building improvements shorter of remaining life of the building or useful life Building (leasehold interest) lesser of 40 years or remaining term of the lease Property under capital lease remaining lease term Furniture and fixtures four to seven years Tenant improvements shorter of remaining term of the lease or useful life Depreciation expense (including amortization of capital lease assets) totaled $ 783.5 million, $ 523.8 million , and $ 338.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Included in 2015 is $131.8 million of accelerated depreciation expense related to vacating the properties that comprise the One Vanderbilt development site. On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be other than temporarily impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted) to be generated by the property is less than the carrying value of the property. To the extent impairment has occurred, the loss will be measured as the excess of the carrying amount of the property over the calculated fair value of the property. We also evaluate our real estate properties for potential impairment when a real estate property has been classified as held for sale. Real estate assets held for sale are valued at the lower of either their carrying value or fair value less costs to sell. We do not believe that there were any indicators of impairment at any of our consolidated properties at December 31, 2016 . During the second quarter of 2016, we recorded a $10.4 million charge in connection with the sale of one property, 500 West Putnam, which closed in the third quarter of 2016. This charge is included in depreciable real estate reserves in the consolidated statements of operations. During the third quarter of 2015, we recorded a $19.2 million charge in connection with the sale of two of our properties, which closed in the fourth quarter of 2015. This charge is included in depreciable real estate reserves in the consolidated statements of operations. During the fourth quarter of 2015, we entered into an agreement to sell 885 Third Avenue and recorded a $6.6 million charge which was included in gain on sale of real estate, net in the consolidated statement of operations. At December 31, 2015, 885 Third Avenue was not reclassified as held for sale as a result of not meeting the criteria in ASC 360-10, Property, Plant and Equipment - Impairment and Disposal of Long-Lived Assets. We do not anticipate meeting the criteria for the full accrual method in ASC 360-20, Property, Plant and Equipment - Real Estate Sales until the third quarter of 2017, as a result the property will remain on our consolidated balance sheet until the criteria is met. We incur a variety of costs in the development and leasing of our properties. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year after major construction activity ceases. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction. Results of operations of properties acquired are included in the consolidated statements of operations from the date of acquisition. We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their fair values on the acquisition date. We expense transaction costs related to the acquisition of certain assets as incurred, which are included in transaction related costs on our consolidated statements of operations. In January, 2017, the FASB published ASU No. 2017-01, Business Combinations: Clarifying the Definition of a Business, which provides guidance as to whether transaction costs should be expensed or capitalized. Refer to Note 2, Accounting Standards Updates for the Company's adoption of the new guidance. When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of operations. In December 2015, we recognized a purchase price fair value adjustment of $40.1 million in connection with the consolidation of 600 Lexington Avenue. In May 2014, we recognized a purchase price fair value adjustment of $71.4 million in connection with the consolidation of 388-390 Greenwich Street. These acquisitions were previously accounted for as investments in unconsolidated joint ventures. We allocate the purchase price of real estate to land and building (inclusive of tenant improvements) and, if determined to be material, intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases. We depreciate the amount allocated to building (inclusive of tenant improvements) over their estimated useful lives, which generally range from three to 40 years. We amortize the amount allocated to the above- and below-market leases over the remaining term of the associated lease, which generally range from one to 14 years, and record it as either an increase (in the case of below-market leases) or a decrease (in the case of above-market leases) to rental income. We amortize the amount allocated to the values associated with in-place leases over the expected term of the associated lease, which generally ranges from one to 14 years. If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The tenant improvements and origination costs are amortized as an expense over the remaining life of the lease (or charged against earnings if the lease is terminated prior to its contractual expiration date). We assess fair value of the leases based on estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. To the extent acquired leases contain fixed rate renewal options that are below-market and determined to be material, we amortize such below-market lease value into rental income over the renewal period. As of December 31, 2016 , the weighted average amortization period for above-market leases, below-market leases, and in-place lease costs is 5.1 years, 24.0 years, and 9.9 years, respectively. We recognized $196.2 million, $38.7 million , and $ 23.3 million of rental revenue for the years ended December 31, 2016 , 2015 , and 2014 respectively, for the amortization of aggregate below-market leases in excess of above-market leases and a reduction in lease origination costs, resulting from the allocation of the purchase price of the applicable properties. Included in rental revenue for the year ended December 31, 2016 is $172.4 million related to the amortization of below-market leases at 388-390 Greenwich Street as a result of the tenant exercising their option to purchase the property and entering into an agreement to accelerate the sale. We recognized as a reduction to interest expense the amortization of the above-market rate mortgages assumed of $2.8 million, $2.3 million , and $5.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Identified intangible assets (included in other assets): Gross amount $ 651,099 $ 939,518 Accumulated amortization (410,930 ) (403,747 ) Net (1) $ 240,169 $ 535,771 Identified intangible liabilities (included in deferred revenue): Gross amount $ 655,930 $ 866,561 Accumulated amortization (464,749 ) (486,928 ) Net (1) $ 191,181 $ 379,633 ____________________________________________________________________ (1) As of December 31, 2016 , no net intangible assets and no net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale. The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands): 2017 $ (19,286 ) 2018 (17,022 ) 2019 (16,300 ) 2020 (15,279 ) 2021 (6,356 ) The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands): 2017 $ 24,801 2018 17,600 2019 14,780 2020 12,742 2021 8,986 In February 2016, we closed on the sale of 885 Third Avenue but did not meet the criteria for sale accounting under the full accrual method in ASC 360-20, Property, Plant and Equipment - Real Estate Sales. As a result the property remains on our consolidated balance sheet until the criteria is met. Cash and Cash Equivalents We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents. Restricted Cash Restricted cash primarily consists of security deposits held on behalf of our tenants, interest reserves, as well as capital improvement and real estate tax escrows required under certain loan agreements. Fair Value Measurements See Note 16, "Fair Value Measurements." Investment in Marketable Securities We designate a security as held-to-maturity, available-for-sale, or trading at acquisition. As of December 31, 2016 , we did not have any securities designated as held-to-maturity or trading. We account for our available-for-sale securities at fair value pursuant to Accounting Standards Codification, or ASC, 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Any unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component. The cost of bonds and marketable securities sold is determined using the specific identification method. At December 31, 2016 and 2015 , we held the following marketable securities (in thousands): December 31, 2016 2015 Equity marketable securities $ 48,315 $ 4,704 Mortgage-backed securities 36,795 40,434 Total marketable securities available-for-sale $ 85,110 $ 45,138 The cost basis of the commercial mortgage-backed securities was $36.0 million and $38.7 million at December 31, 2016 and 2015 , respectively. These securities mature at various times through 2049. The cost basis of the equity marketable securities was $43.3 million and $4.3 million at December 31, 2016 and 2015 , respectively. During the year ended December 31, 2016 , we disposed of marketable securities for aggregate net proceeds of $7.0 million and realized loss of $0.1 million , which is included in gain on sale of investment in marketable securities on the consolidated statements of operations. We did not sell any of our marketable securities during the year ended December 31, 2015 . Investments in Unconsolidated Joint Ventures We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity in net income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us. The Company has performance guarantees under master leases at two joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures." We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at December 31, 2016 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some of the residual profit from such projects. When the risk and rewards of these arrangements are essentially the same as an investor or joint venture partner, we account for these arrangements as real estate investments under the equity method of accounting for investments. Otherwise, we account for these arrangements consistent with our loan accounting for our debt and preferred equity investments. Deferred Lease Costs Deferred lease costs consist of fees and direct costs incurred to initiate and renew operating leases and are amortized on a straight-line basis over the related lease term. Certain of our employees provide leasing services to the wholly-owned properties. For the years ended December 31, 2016 , 2015 and 2014 , $15.4 million , $15.4 million and $15.1 million of their compensation, respectively, was capitalized and is amortized over an estimated average lease term of seven years. Deferred Financing Costs Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close. Deferred debt issuance costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. Revenue Recognition Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year. We record a gain on sale of real estate when title is conveyed to the buyer, subject to the buyer's financial commitment being sufficient to provide economic substance to the sale and provided that we have no substantial economic involvement with the buyer. Interest income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt. Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as an adjustment to the interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cash flows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield. Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received. We may syndicate a portion of the loans that we originate or sell the loans individually. When a transaction meets the criteria for sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, original issue discounts, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of operations. Any fees received at the time of sale or syndication are recognized as part of investment income. Asset management fees are recognized on a straight-line basis over the term of the asset management agreement. Allowance for Doubtful Accounts We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required. Reserve for Possible Credit Losses The expense for possible credit losses in connection with debt and preferred equity investments is the charge to earnings to increase the allowance for possible credit losses to the level that we estimate to be adequate, based on Level 3 data, considering delinquencies, loss experience and collateral quality. Other factors considered include geographic trends, product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish a provision for possible credit loss on each individual investment. When it is probable that we will be unable to collect all amounts contractually due, the investment is considered impaired. Where impairment is indicated on an investment that is held to maturity, a valuation allowance is measured based upon the excess of the recorded investment amount over the net fair value of the collateral. Any deficiency between the carrying amount of an asset and the calculated value of the collateral is charged to expense. We continue to assess or adjust our estimates based on circumstances of a loan and the underlying collateral. If additional information reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during years ended December 31, 2016 , 2015 , and 2014 . Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment. Rent Expense Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred lease payable on the consolidated balance sheets. Underwriting Commissions and Costs Underwriting commissions and costs incurred in connection with our stock offerings are reflected as a reduction of additional paid-in-capital. Exchangeable Debt Instruments The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, are bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate

Property Acquisitions

Property Acquisitions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions 2016 Acquisitions During the year ended December 31, 2016 , the property listed below was acquired from a third party. The following summarizes our final allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of this acquisition (in thousands): 183 Broadway Acquisition Date March 2016 Ownership Type Fee Interest Property Type Retail/Residential Purchase Price Allocation: Land $ 5,799 Building and building leasehold 23,431 Above-market lease value — Acquired in-place leases 773 Other assets, net of other liabilities 20 Assets acquired 30,023 Mark-to-market assumed debt — Below-market lease value (1,523 ) Derivatives — Liabilities assumed (1,523 ) Purchase price $ 28,500 Net consideration funded by us at closing, excluding consideration financed by debt $ 28,500 Equity and/or debt investment held $ — Debt assumed $ — ____________________________________________________________________ (1) Based on our preliminary analysis of the purchase price, we had allocated $26.6 million and $1.9 million to land and building, respectively. We finalized the allocation in the fourth quarter of 2016. The impact to our consolidated statements of operations for the three months ended December 31, 2016 was an increase in rental revenue of $0.2 million for the amortization of aggregate below-market leases and an additional $2.1 million of depreciation expense. 2015 Acquisitions During the year ended December 31, 2016 , we finalized the purchase price allocations for the following 2015 acquisitions based on facts and circumstances that existed at the acquisition date for each property (in thousands): 600 Lexington Avenue (1)(2) 187 Broadway and 5 & 7 Dey Street (1)(3) 11 Madison Avenue (1) 110 Greene Street (1)(4) Upper East Side Residential (1)(5) 1640 Flatbush Avenue (1) Acquisition Date December 2015 August 2015 August 2015 July 2015 June 2015 March 2015 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Office Residential/Retail Office Office Residential/Retail Retail Purchase Price Allocation: Land $ 81,670 $ 20,266 $ 675,776 $ 45,120 $ 48,152 $ 6,226 Building and building leasehold 182,447 42,468 1,553,602 215,470 — 501 Above-market lease value 3,320 17 19,764 — — — Acquired in-place leases 22,449 3,621 366,949 8,967 1,922 146 Other assets, net of other liabilities — — — — — — Assets acquired 289,886 66,372 2,616,091 269,557 50,074 6,873 Mark-to-market assumed debt (55 ) — — — — — Below-market lease value (5,831 ) (3,226 ) (187,732 ) (14,557 ) — (73 ) Derivatives — — — — — — Liabilities assumed (5,886 ) (3,226 ) (187,732 ) (14,557 ) — (73 ) Purchase price $ 284,000 $ 63,146 $ 2,428,359 $ 255,000 $ 50,074 $ 6,800 Net consideration funded by us at closing, excluding consideration financed by debt $ 79,085 $ — $ — $ — $ — $ — Equity and/or debt investment held $ 54,575 $ — $ — $ — $ — $ — Debt assumed $ 112,795 $ — $ — $ — $ — $ — ____________________________________________________________________ (1) Based on our preliminary analysis of the purchase price, we had allocated $97.0 million and $180.2 million to land and building, respectively, at 600 Lexington Avenue, $22.1 million and $41.0 million to land and building, respectively, at 187 Broadway and 5&7 Dey Street, $849.9 million and $1.6 billion to land and building, respectively, at 11 Madison Avenue, $89.3 million and $165.8 million to land and building, respectively, at 110 Greene Street, and $17.5 million and $32.5 million to land and building, respectively, at the Upper Eastside Residential Property and $6.1 million and $0.7 million to land and building, respectively, at 1640 Flatbush Avenue. The impact to our consolidated statements of operations for the twelve months ended December 31, 2015 was an increase in rental revenue of $7.8 million for the amortization of aggregate below-market leases and an additional $18.5 million of depreciation expense. (2) In December 2015, we acquired Canada Pension Plan Investment Board's 45% interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $277.3 million . We recognized a purchase price fair value adjustment of $40.1 million upon closing of this transaction. This property, which we initially acquired in May 2010, was previously accounted for as an investment in unconsolidated joint ventures. (3) We acquired this property for consideration that included the issuance of $10.0 million and $26.9 million aggregate liquidation preferences of Series R and S Preferred Units, respectively, of limited partnership interest of the Operating Partnership and cash. (4) We acquired a 90.0% controlling interest in this property for consideration that included the issuance of $5.0 million and $6.7 million aggregate liquidation preferences of Series P and Q Preferred Units, respectively, of limited partnership interest of the Operating Partnership and cash. (5) We, along with our joint venture partner, acquired this property for consideration that included the issuance of $13.8 million aggregate liquidation preference of Series N Preferred Units of limited partnership interest of the Operating Partnership and cash. We hold a 95.1% controlling interest in this joint venture. 2014 Acquisitions During the year ended December 31, 2014, the properties listed below were acquired from third parties. The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands): 102 Greene Street (1) 635 Madison Avenue (1) 719 Seventh Avenue (1)(2) 115 Spring Street (1) 388-390 Greenwich Street (1)(3) Acquisition Date October 2014 September 2014 July 2014 July 2014 May 2014 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Retail Land Development Retail Office Purchase Price Allocation: Land $ 8,215 $ 205,632 $ 41,850 $ 11,078 $ 516,292 Building and building leasehold 26,717 15,805 — 44,799 964,434 Above-market lease value — — — — — Acquired in-place leases 1,015 17,345 — 2,037 302,430 Other assets, net of other liabilities 3 — — — 6,495 Assets acquired 35,950 238,782 41,850 57,914 1,789,651 Mark-to-market assumed debt — — — — — Below-market lease value 3,701 85,036 — 4,789 186,782 Derivatives — — — — 18,001 Liabilities assumed 3,701 85,036 — 4,789 204,783 Purchase price $ 32,249 $ 153,746 $ 41,850 $ 53,125 $ 1,584,868 Net consideration funded by us at closing, excluding consideration financed by debt $ 32,249 $ 153,746 $ 41,850 $ 53,125 $ 208,614 Equity and/or debt investment held $ — $ — $ — $ — $ 148,025 Debt assumed $ — $ — $ — $ — $ 1,162,379 ____________________________________________________________________ (1) Based on our preliminary analysis of the purchase price, we had allocated $11.3 million and $21.0 million to land and building, respectively, at 102 Greene Street, $153.7 million to land at 635 Madison Avenue, $14.4 million and $26.7 million to land and building, respectively, at 719 Seventh Avenue, $15.9 million and $37.2 million to land and building, respectively, at 115 Spring Street and $558.7 million and $1.0 billion to land and building, respectively, at 388-390 Greenwich. The impact to our consolidated statements of operations for the twelve months ended December 31, 2015 was $7.6 million in rental revenue for the amortization of aggregate below-market leases and $10.3 million of depreciation expense. (2) We, along with our joint venture partner, acquired this property for consideration that included the issuance of $14.1 million aggregate liquidation preference of Series L Preferred Units of limited partnership interest of the Operating Partnership and $9.5 million aggregate liquidation preference of Series K Preferred Units of limited partnership interest of the Operating Partnership. We hold a 75.0% controlling interest in this joint venture. (3) In May 2014, we acquired Ivanhoe Cambridge, Inc.'s 49.65% economic interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $1.585 billion . Simultaneous with the closing, we refinanced the previous mortgage with a $1.45 billion mortgage. We also assumed the existing derivative instruments, which swapped $504.0 million of the mortgage to fixed rate (in October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on an additional $500.0 million portion of this mortgage. See Note 8, "Mortgages and Other Loans Payable" for further details). We recognized a purchase price fair value adjustment of $71.4 million upon closing of this transaction. This property, which we initially acquired in December 2007, was previously accounted for as an investment in unconsolidated joint ventures. For business combinations achieved in stages, the acquisition-date fair value of our equity interest in a property immediately before the acquisition date is determined based on estimated cash flow projections that utilize available market information and discount and capitalization rates that we deem appropriate. Estimates of future cash flows are based on a number of factors including historical operating results, known and anticipated trends, and market and economic conditions. The acquisition-date fair value of the equity interest in 600 Lexington Avenue and 388-390 Greenwich Street, which were acquired in 2015 and 2014, respectively, immediately before the acquisition date as well as the purchase price fair value, as determined in accordance with the methodology set out in the prior sentence, are as follows (in thousands): 600 Lexington Avenue 388-390 Greenwich Street Contract purchase price $ 284,000 $ 1,585,000 Net consideration funded by us at closing, excluding consideration financed by debt (79,085 ) (208,614 ) Debt assumed (112,795 ) (1,162,379 ) Fair value of retained equity interest 92,120 214,007 Equity and/or debt investment held (54,575 ) (148,025 ) Other (1) 2,533 5,464 Purchase price fair value adjustment $ 40,078 $ 71,446 ___________________________________________________________________ (1) Includes the acceleration of a deferred leasing commission from the joint venture to the Company. Pro Forma Unaudited The following table summarizes, on an unaudited pro forma basis, the results of operations of 11 Madison Avenue, which are included in the consolidated results of operations for years ended December 31, 2015 and 2014 as though the acquisition of 11 Madison Avenue was completed on January 1, 2014. The supplemental pro forma data is not necessarily indicative of what the actual results of operations would have been assuming the transactions had been completed as set forth above, nor do they purport to represent our results of operations for future periods. Year Ended December 31, (in thousands, except per share/unit amounts) 2015 2014 Actual revenues since acquisition $ 29,865 Actual net income since acquisition 159 Pro forma revenues 1,657,937 1,540,525 Pro forma income from continuing operations (1) 102,440 376,710 Pro forma basic earnings per share $ 0.76 $ 7.00 Pro forma diluted earnings per share $ 0.75 $ 6.92 Pro forma basic earnings per unit $ 0.76 $ 7.00 Pro forma diluted earnings per unit $ 0.75 $ 6.92 ______________________________________________________________________ (1) The pro forma income from continuing operations for the years ended December 31, 2015 and 2014 includes the effect of the incremental borrowings, including a $ 1.4 billion , 10 -year, interest only, fixed rate mortgage financing carrying a per annum stated interest rate of 3.838% to complete the acquisition and the preliminary allocation of purchase price. In addition, the pro forma income from continuing operations for the year ended December 31, 2014 was adjusted to include the sale of real estate assets for properties that have closed either subsequent to December 31, 2015 or we are currently under contract to sell in connection with 11 Madison Avenue, as if the sales were completed on January 1, 2014. The pro forma income from continuing operations for the year ended December 31, 2015 excludes these sales.

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Property Dispositions	Properties Held for Sale and Property Dispositions Properties Held for Sale As of December 31, 2016 , no properties in our portfolio were classified as held for sale. Property Dispositions The following table summarizes the properties sold during the years ended December 31, 2016 , 2015 , and 2014 : Property Disposition Date Property Type (unaudited)Approximate Usable Square Feet Sales Price (1) (in millions) Gain (Loss) on Sale (2) (in millions) 400 East 57th Street October 2016 Residential 290,482 $ 83.3 $ 23.9 11 Madison Avenue (3) August 2016 Office 2,314,000 2,605.0 3.6 500 West Putnam July 2016 Office 121,500 41.0 (10.4 ) 388 Greenwich June 2016 Office 2,635,000 2,002.3 206.5 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) 248-252 Bedford Avenue February 2016 Residential 66,611 55.0 15.3 885 Third Avenue (4) February 2016 Land 607,000 453.0 — 140-150 Grand Street (5) December 2015 Office/Development 215,100 32.0 (20.1 ) 570 & 574 Fifth Avenue December 2015 Development 24,327 125.4 24.6 120 West 45th Street September 2015 Office 440,000 365.0 58.6 131-137 Spring Street (6) August 2015 Office 68,342 277.8 101.1 180 Maiden Lane January 2015 Office 1,090,000 470.0 17.0 2 Herald Square November 2014 Land 354,400 365.0 18.8 985-987 Third Avenue July 2014 Development 13,678 68.7 29.8 673 First Avenue May 2014 Office 422,000 145.0 117.6 ____________________________________________________________________ (1) Sales price represents the actual sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 400 East 57th Street, 11 Madison Avenue, 388 Greenwich, 248-252 Bedford Avenue, 570 & 574 Fifth Avenue, 120 West 45th Street, 131-137 Spring Street, 180 Maiden Lane, 2 Herald Square, 985-987 Third Avenue, and 673 First Avenue are net of $1.0 million , $0.6 million , $1.6 million , $1.3 million , $4.0 million , $2.0 million , $4.1 million , $0.8 million , $2.5 million , $1.3 million , and $3.4 million in employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In August 2016, we sold a 40% interest in 11 Madison Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property was accounted for under the profit sharing method. In November 2016, the Company obtained consent to the modifications to the mortgage on the property, which resulted in the Company achieving sale accounting on the transaction. See Note 6, "Investments in Unconsolidated Joint Ventures." (4) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and, therefore, remains consolidated. We expect to deconsolidate the property in or before July 2017. An estimated loss relating to the sale of $6.6 million was recorded in December 2015. (5) Gain/(loss) on sale includes a $19.2 million charge that was recorded during the third quarter of 2015. This charge is included in depreciable real estate reserves in the consolidated statement of operations. (6) We sold an 80% interest in 131-137 Spring Street and have subsequently accounted for our interest in the properties as an investment in unconsolidated joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures." Discontinued Operations The Company adopted ASU 2014-08 effective January 1, 2015 which raised the threshold for disposals to qualify as discontinued operations to include only dispositions that represent a strategic shift in an entity’s operations. The guidance was applied prospectively for new disposals. As a result, the Company classified 242-252 Bedford Avenue in Brooklyn, New York as held for sale as of December 31, 2015, 570 & 574 Fifth Avenue and 140-150 Grand Street in White Plains, New York as held for sale as of September 30, 2015 and 131-137 Spring Street and 120 West 45th Street as of June 30, 2015 and included the results of operations in continuing operations for all periods presented. Discontinued operations included the results of operations of real estate assets sold or held for sale prior to January 1, 2015. This included 180 Maiden Lane, which was held for sale at December 31, 2014 and sold in January 2015, and 2 Herald Square, 985-987 Third Avenue and 673 First Avenue, which were sold during 2014. The following table summarizes net income from discontinued operations for the years ended December 31, 2016 , 2015 , and 2014 respectively (in thousands): Year Ended December 31, 2016 2015 2014 Revenues Rental revenue $ — $ 236 $ 51,090 Escalation and reimbursement revenues — (127 ) 4,646 Other income — — 23 Total revenues — 109 55,759 Operating expenses — (631 ) 7,772 Real estate taxes — 250 7,156 Ground rent — — 3,001 Transaction related costs — (49 ) 89 Interest expense, net of interest income — 109 12,652 Amortization of deferred financing costs — 3 433 Depreciation and amortization — — 5,581 Total expenses — (318 ) 36,684 Net income from discontinued operations $ — $ 427 $ 19,075

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments During the years ended December 31, 2016 and 2015 , our debt and preferred equity investments, net of discounts and deferred origination fees, increased $1,015 million and $781 million , respectively, due to originations, purchases, advances under future funding obligations, discount and fee amortization, and paid-in-kind interest, net of premium amortization. We recorded repayments, participations and sales of $1,045 million and $520 million during the years ended December 31, 2016 and 2015 , respectively, which offset the increases in debt and preferred equity investments. Debt Investments As of December 31, 2016 and 2015 , we held the following debt investments with an aggregate weighted average current yield of 9.34% at December 31, 2016 (in thousands): Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Jr. Mortgage Participation/Mezzanine Loan $ — $ 1,109,000 $ 193,422 $ 104,661 March 2017 Mezzanine Loan (3a) — 502,100 66,129 41,115 June 2017 Mortgage Loan (4) — — 26,311 26,262 February 2019 Mortgage Loan — — 380 513 August 2019 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan (3b) — 88,466 12,692 19,936 November 2023 Mezzanine Loan (3c) — 115,000 12,925 24,916 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 15,000 — November 2026 Mezzanine Loan (5) — — — 72,102 Mezzanine Loan (6) — — — 49,691 Jr. Mortgage Participation (7) — — — 49,000 Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Other (7)(8) — — — 23,510 Other (7)(8) — — — 66,183 Total fixed rate $ — $ 2,264,566 $ 360,359 $ 511,389 Floating Rate Investments: Mortgage/Mezzanine Loan (3d)(9) 36,042 — 145,239 134,264 January 2017 Mezzanine Loan (10) — 118,949 29,998 28,551 January 2017 Mezzanine Loan (3e)(11) — 40,000 15,369 68,977 June 2017 Mortgage/Mezzanine Loan — — 32,847 — June 2017 Mortgage/Mezzanine Loan — — 22,959 22,877 July 2017 Mortgage/Mezzanine Loan — — 16,960 16,901 September 2017 Mortgage/Mezzanine Loan 3,479 — 20,423 19,282 October 2017 Mezzanine Loan — 60,000 14,957 14,904 November 2017 Mezzanine Loan (3f) — 85,000 15,141 29,505 December 2017 Mezzanine Loan (3g) — 65,000 14,656 28,563 December 2017 Mortgage/Mezzanine Loan (3h) 795 — 15,051 14,942 December 2017 Jr. Mortgage Participation — 40,000 19,913 19,846 April 2018 Mezzanine Loan — 175,000 34,844 34,725 April 2018 Mortgage/Mezzanine Loan (12) 523 20,523 10,863 31,210 August 2018 Mortgage Loan — — 19,840 — August 2018 Mezzanine Loan — 65,000 14,880 — August 2018 Mezzanine Loan — 37,500 14,648 — September 2018 Mezzanine Loan 2,324 45,025 34,502 — October 2018 Mezzanine Loan — 335,000 74,476 — November 2018 Mezzanine Loan — 33,000 26,850 26,777 December 2018 Mezzanine Loan 3,317 165,326 56,114 52,774 December 2018 Mezzanine Loan 15,794 259,229 63,137 49,625 December 2018 Mezzanine Loan 14,715 199,935 64,505 — December 2018 Mezzanine Loan — 45,000 12,104 — January 2019 Mezzanine Loan 6,383 16,383 5,410 — January 2019 Mezzanine Loan — 38,000 21,891 21,845 March 2019 Mezzanine Loan — 265,000 24,707 — April 2019 Mortgage/Jr. Mortgage Participation Loan 33,573 183,300 65,554 — August 2019 Mezzanine Loan 2,500 187,500 37,322 — September 2019 Mortgage/Mezzanine Loan 82,888 — 111,819 — September 2019 Mortgage/Mezzanine Loan 35,630 — 33,682 — January 2020 Mezzanine Loan (13) 32,502 445,483 125,911 — January 2020 Jr. Mortgage Participation/Mezzanine Loan — 30,000 15,606 — July 2021 Mezzanine Loan (14) — — — 49,751 Mezzanine Loan (14) — — — 13,731 Mezzanine Loan (15) — — — 99,530 Mortgage/Mezzanine Loan (16) — — — 94,901 Jr. Mortgage Participation/Mezzanine Loan (5) — — — 20,510 Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Mezzanine Loan (17) — — — 22,625 Mezzanine Loan (18) — — — 74,700 Mezzanine Loan (19) — — — 66,398 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 18,395 Mezzanine Loan (20) — — — 40,346 Total floating rate $ 270,465 $ 2,955,153 $ 1,232,178 $ 1,116,455 Total $ 270,465 $ 5,219,719 $ 1,592,537 $ 1,627,844 ____________________________________________________________________ (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised options. (3) Carrying value is net of the following amount that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting: (a) $41.3 million , (b) $5.0 million , (c) $12.0 million , (d) $36.3 million , (e) $14.5 million , (f) $14.6 million , (g) $14.1 million , and (h) $5.1 million . (4) In September 2014, we acquired a $26.4 million mortgage loan at a $0.2 million discount and a $5.7 million junior mortgage participation at a $5.7 million discount. The junior mortgage participation was a nonperforming loan at acquisition and is currently on non-accrual status. (5) This loan was repaid in July 2016. (6) In April 2016 we executed a purchase option to acquire a 20% interest in the underlying asset at a previously agreed upon purchase option valuation, and our mezzanine loan was simultaneously repaid. (7) This loan was repaid in March 2016. (8) This loan was collateralized by defeasance securities. (9) This loan was refinanced at maturity in January 2017 by us at market rates, and therefore it was not considered a troubled-debt restructuring. (10) This loan was extended in January 2017. (11) In March 2016, the mortgage was sold. (12) In January 2016, the loans were modified. In March 2016, the mortgage was sold. (13) $66.1 million of outstanding principal was syndicated in February 2017. (14) This loan was repaid in December 2016. (15) This loan was repaid in November 2016. (16) This loan was repaid in September 2016. (17) This loan was repaid in June 2016. (18) This loan was repaid in May 2016. (19) In March 2016, we contributed our interest in the loan in exchange for a joint venture interest which is now accounted for under the equity method of accounting. It is included in unconsolidated joint ventures on the consolidated balance sheets. (20) This loan was repaid in February 2016. Preferred Equity Investments As of December 31, 2016 and 2015 , we held the following preferred equity investments with an aggregate weighted average current yield of 8.16% at December 31, 2016 (in thousands): Type December 31, 2016 Future Funding Obligations December 31, 2016 December 31, 2016 (1) December 31, 2015 (1) Mandatory Redemption (2) Preferred Equity $ — $ 71,486 $ 9,982 $ 9,967 March 2018 Preferred Equity — 58,786 37,893 32,209 November 2018 $ — $ 130,272 $ 47,875 $ 42,176 ____________________________________________________________________ (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. The following table is a rollforward of our total loan loss reserves at December 31, 2016 , 2015 and 2014 (in thousands): December 31, 2016 2015 2014 Balance at beginning of year $ — $ — $ 1,000 Expensed — — — Recoveries — — — Charge-offs and reclassifications — — (1,000 ) Balance at end of period $ — $ — $ — At December 31, 2016 , 2015 and 2014 , all debt and preferred equity investments were performing in accordance with the terms of the relevant investments, with the exception of the junior mortgage participation acquired in September 2014, which has a carrying value of zero discussed in subnote 4 of the Debt Investments table above. We have determined that we have one portfolio segment of financing receivables at December 31, 2016 and 2015 comprising commercial real estate which is primarily recorded in debt and preferred equity investments. Included in other assets is an additional amount of financing receivables totaling $99.5 million and $121.5 million at December 31, 2016 and 2015 , respectively. No financing receivables were 90 days past due at December 31, 2016 .

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures We have investments in several real estate joint ventures with various partners. As of December 31, 2016 650 Fifth Avenue, 800 Third Avenue, 21 East 66th Street, 605 West 42 nd Street, 333 East 22nd Street, and certain properties within the Stonehenge Portfolio are VIEs in which we are not the primary beneficiary. Our net equity investment in these VIEs was $220.1 million as of December 31, 2016 . As of December 31, 2015 , 650 Fifth Avenue and 33 Beekman were VIEs in which we were not the primary beneficiary. Our net equity investment in these VIEs was $39.7 million as of December 31, 2015 . Our maximum loss is limited to the amount of our equity investment in these VIEs. All other investments below are voting interest entities. As we do not control the joint ventures listed below, we account for them under the equity method of accounting. The table below provides general information on each of our joint ventures as of December 31, 2016 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 January 2000 $ 95,800 717 Fifth Avenue Jeff Sutton/Private Investor 10.92% 10.92% 119,500 September 2006 251,900 800 Third Avenue Private Investors 60.52% 60.52% 526,000 December 2006 285,000 1745 Broadway Ivanhoe Cambridge, Inc. 56.88% 56.88% 674,000 April 2007 520,000 Jericho Plaza (3) Onyx Equities/Credit Suisse 11.67% 11.67% 640,000 April 2007 210,000 11 West 34th Street Private Investor/ Jeff Sutton 30.00% 30.00% 17,150 December 2010 10,800 3 Columbus Circle (4) The Moinian Group 48.90% 48.90% 741,500 January 2011 500,000 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 March 2011 400,000 1552-1560 Broadway (5) Jeff Sutton 50.00% 50.00% 35,897 August 2011 136,550 724 Fifth Avenue Jeff Sutton 50.00% 50.00% 65,040 January 2012 223,000 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 February 2012 252,500 521 Fifth Avenue Plaza Global Real Estate Partners LP 50.50% 50.50% 460,000 November 2012 315,000 21 East 66th Street (6) Private Investors 32.28% 32.28% 16,736 December 2012 75,000 650 Fifth Avenue (7) Jeff Sutton 50.00% 50.00% 69,214 November 2013 — 121 Greene Street Jeff Sutton 50.00% 50.00% 7,131 September 2014 27,400 Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 175-225 Third Street Brooklyn, New York KCLW 3rd Street LLC/LIVWRK LLC 95.00% 95.00% — October 2014 74,600 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 November 2014 295,000 Stonehenge Portfolio Various Various Various 2,046,733 February 2015 36,668 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 76 11th Avenue (8) Oxford/Vornado 33.33% 35.09% 764,000 March 2016 138,240 605 West 42nd Street (9) The Moinian Group 20.00% 20.00% 927,358 April 2016 759,000 11 Madison Avenue (10) PGIM Real Estate 60.00% 60.00% 2,314,000 August 2016 2,605,000 333 East 22nd Street (11) Private Investors 33.33% 33.33% 26,926 August 2016 — 400 E 57th Street (12) Blackrock, Inc and Stonehenge Partners 51.00% 41.00% 290,482 October 2016 170,000 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of December 31, 2016 . Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) Acquisition date and price represent the date on which the Company initially acquired an interest in the joint venture and the actual or implied gross purchase price for the joint venture on that date. Acquisition date and price are not adjusted for subsequent acquisitions or dispositions of interest. (3) In connection with the restructuring of the joint venture and the loan on the property, our 20.26% ownership increased by 57.52% in October 2015. Our ownership percentage was reduced 66.11% in the first quarter of 2016 upon completion of the restructuring of the venture. (4) As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns floors three through eight at the property. Because the joint venture has an option to repurchase these floors, the gain associated with this sale was deferred. (5) The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet. The joint venture also owns a long-term leasehold interest in the retail space and certain other spaces at 1560 Broadway, which is adjacent to 1552 Broadway. (6) We hold a 32.28% interest in three retail and two residential units at the property and a 16.14% interest in three residential units at the property. (7) The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. In connection with the ground lease obligation, SLG provided a performance guaranty and our joint venture partner executed a contribution agreement to reflect its pro rata obligation. In the event the property is converted into a condominium unit and the landlord elects the purchase option, the joint venture shall be obligated to acquire the unit at the then fair value. In November 2016, the joint venture entered into a lease for an additional 36,890 square feet at the property for a term lasting sixteen years and ten months. (8) The joint venture owns two mezzanine notes secured by interests in the entity that owns 76 11th Avenue. The difference between our ownership interest and our economic interest results from our right to 50% of the total exit fee while each of our partners is entitled to receive 25% of the total exit fee and our right to 38% of the total extension fee while each of our partners is entitled to receive 31% of the total extension fee. (9) The Company was granted an option to purchase the interest at an agreed upon valuation in July 2014 when it originated a $50.0 million mezzanine loan to the project's developer. The mezzanine loan was repaid prior to the closing of the Company's acquisition of its joint venture interest. (10) In August 2016, we closed on the sale of a 40% interest in 11 Madison. The sale did not meet the criteria for sale accounting and as a result the property was accounted for under the profit sharing method. Under the profit sharing method the Company recognized its share of the operations of the property and also recognized the other partner's share of depreciation. In November 2016, the Company obtained consent to the modifications to the mortgage on the property, which resulted in the Company achieving sale accounting on the transaction. The achievement of sale accounting discontinued recognition of the other partner's share of depreciation from that date and had no effect on the balance sheet presentation of the investment. Included in equity in net income from unconsolidated joint ventures is $8.4 million of depreciation for the year ended December 31, 2016 representing the other partner's share of depreciation. (11) The joint venture acquired a leasehold interest in the property in October 2016. (12) In October 2016, the Company sold a 49% interest in this property to Blackrock, Inc. The Company's interest in the property was sold within a consolidated joint venture owned 90% by the Company and 10% by Stonehenge. The transaction resulted in the deconsolidation of the venture's remaining 51% interest in the property. The Company's joint venture with Stonehenge remains consolidated resulting in the combined 51% interest being shown within investments in unconsolidated joint ventures on the Company's balance sheet. Acquisition, Development and Construction Arrangements Based on the characteristics of the following arrangements, which are similar to those of an investment, combined with the expected residual profit of not greater than 50% , we have accounted for these debt and preferred equity investments under the equity method. As of December 31, 2016 and 2015 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type December 31, 2016 December 31, 2015 Initial Maturity Date Mezzanine Loan and Preferred Equity $ 100,000 $ 99,936 March 2017 Mezzanine Loan (1) 45,622 45,942 February 2022 Mezzanine Loan (2) 24,542 — July 2036 $ 170,164 $ 145,878 (1) We have an option to convert our loan to an equity interest subject to certain conditions. We have determined that our option to convert the loan to equity is not a derivative financial instrument pursuant to GAAP. (2) The Company has the ability to convert this loan into an equity position starting in 2021 and the borrower is able to force this conversion in 2024. Sale of Joint Venture Interests or Properties The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2016 , 2015 , and 2014 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain (Loss) on Sale (in thousands) (2) EOP Denver 0.48% September 2016 Ownership Interest $ 180,700 $ 300 33 Beekman (3) 45.90% May 2016 Property 196,000 33,000 EOP Denver 4.79% March 2016 Ownership Interest 180,700 2,800 7 Renaissance Square 50.00% March 2016 Property 20,700 4,200 1 Jericho Plaza (4) 66.11% February 2016 Ownership Interest 95,200 3,300 The Meadows 50.00% August 2015 Property 121,100 (1,600 ) 315 West 36th Street 35.50% September 2015 Ownership Interest 115,000 16,300 180 Broadway (5) 25.50% September 2014 Property 222,500 16,500 747 Madison Avenue (6) 33.33% May 2014 Ownership Interest 160,000 — West Coast Office portfolio 42.02% March 2014 Ownership Interest 756,000 85,600 21-25 West 34th Street (7) 49.90% January 2014 Ownership Interest 114,900 20,900 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain or loss. The gain on sale is net of $2.3 million employee compensation awards accrued in connection with the realization of these investment gains as bonuses to certain employees that were instrumental in realizing the gains on sale. (3) In connection with the sale of the property, we also recognized a promote of $10.8 million . (4) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (5) In connection with the sale of the property, we also recognized a promote of $3.3 million . (6) We sold our ownership interest in the joint venture, which owns 100% interest as tenant-in-common in 30 East 65th Street Corporation and the related proprietary lease of five cooperative apartment units in the property. We also recognized a promote of $10.3 million and originated a $30.0 million preferred equity investment. Given our continuing involvement as a preferred equity holder, we deferred the gain on sale of $13.1 million as we did not meet the requirements of a sale under the full accrual method. We, along with our joint venture partners, retained one apartment unit at this property. (7) We sold our ownership interest in the joint venture. We, along with our joint venture partner, retained approximately 91,300 square feet (unaudited) of development rights at the property. Joint Venture Mortgages and Other Loans Payable We generally finance our joint ventures with non-recourse debt. In certain cases we have provided guarantees or master leases for tenant space, which terminate upon the satisfaction of specified circumstances or repayment of the underlying loans. The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2016 and 2015 , respectively, are as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 31, 2016 December 31, 2015 Fixed Rate Debt: 1745 Broadway (2) January 2017 5.68 % $ 340,000 $ 340,000 521 Fifth Avenue November 2019 3.73 % 170,000 170,000 717 Fifth Avenue (3) July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (3) July 2022 6.52 % 355,328 325,704 21 East 66th Street April 2023 3.60 % 12,000 12,000 3 Columbus Circle March 2025 3.61 % 350,000 350,000 11 Madison Avenue September 2025 3.84 % 1,400,000 — 800 Third Avenue February 2026 3.24 % 177,000 20,910 400 East 57th Street November 2026 3.00 % 100,000 — Stonehenge Portfolio (4) Various 4.19 % 362,518 430,627 280 Park Avenue — 692,963 7 Renaissance — 2,927 Total fixed rate debt $ 3,566,846 $ 2,645,131 Floating Rate Debt: 10 East 53rd Street (5) February 2017 2.98 % $ 125,000 $ 125,000 724 Fifth Avenue April 2017 2.90 % 275,000 275,000 1552 Broadway (6) April 2017 4.68 % 185,410 190,409 55 West 46th Street (7) October 2017 2.78 % 157,322 150,000 175-225 Third Street December 2017 4.51 % 40,000 40,000 Jericho Plaza (8) March 2018 4.64 % 76,993 163,750 605 West 42nd Street July 2018 2.91 % 539,000 — 650 Fifth Avenue (9) August 2018 4.10 % 77,500 65,000 280 Park Avenue June 2019 2.51 % 900,000 30,000 121 Greene Street November 2019 1.98 % 15,000 15,000 131-137 Spring Street August 2020 2.03 % 141,000 141,000 11 West 34th Street January 2021 1.93 % 23,000 23,000 100 Park Avenue February 2021 2.23 % 360,000 360,000 21 East 66th Street June 2033 3.00 % 1,726 1,805 Stonehenge Portfolio (10) Various 5.71 % 65,577 10,500 33 Beekman — 73,518 Total floating rate debt $ 2,982,528 $ 1,663,982 Total joint venture mortgages and other loans payable $ 6,549,374 $ 4,309,113 Deferred financing costs, net (95,408 ) (42,565 ) Total joint venture mortgages and other loans payable, net $ 6,453,966 $ 4,266,548 ____________________________________________________________________ (1) Effective weighted average interest rate for the year ended December 31, 2016 , taking into account interest rate hedges in effect during the period. (2) In January 2017, this loan was refinanced with a new $375.0 million mortgage, of which $340.0 million was drawn at closing, with a floating interest rate of LIBOR + 1.85% and a maturity date of January 2020. (3) These loans are comprised of a $300.0 million fixed rate mortgage loan and $355.3 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate. (4) Amount is comprised of $13.1 million , $34.5 million , $139.7 million , and $175.2 million in fixed-rate mortgages that mature in April 2017, November 2017, August 2019, and June 2024, respectively. (5) In February 2017, this loan was refinanced with a new $170.0 million mortgage with a floating interest rate of LIBOR + 2.25% and a maturity date of February 2020. (6) These loans are comprised of a $145.0 million mortgage loan and a $41.5 million mezzanine loan. As of December 31, 2016 , $0.6 million of the mortgage loan and $0.5 million of the mezzanine loan was unfunded. (7) This loan has a committed amount of $190.0 million , of which $32.7 million was unfunded as of December 31, 2016 . (8) We hold an 11.67% non-controlling interest in the joint venture and the property secures a two year $100.0 million loan, of which $77.0 million is currently outstanding. (9) This loan has a committed amount of $97.0 million , of which $19.5 million was unfunded as of December 31, 2016 . (10) Amount is comprised of $55.3 million and $10.2 million in floating-rate mortgages that mature in June 2017 and December 2017, respectively. We act as the operating partner and day-to-day manager for all our joint ventures, except for 800 Third Avenue, Jericho Plaza, 280 Park Avenue, 3 Columbus Circle, 21 East 66th Street, 175-225 Third Street, 605 West 42nd Street, 400 East 57th Street, and the Stonehenge Portfolio. We are entitled to receive fees for providing management, leasing, construction supervision and asset management services to certain of our joint ventures. We earned $8.1 million , $6.9 million and $16.9 million from these services for the years ended December 31, 2016 , 2015 , and 2014 , respectively. In addition, we have the ability to earn incentive fees based on the ultimate financial performance of certain of the joint venture properties. The combined balance sheets for the unconsolidated joint ventures, at December 31, 2016 and 2015 , are as follows (in thousands): December 31, 2016 December 31, 2015 Assets Commercial real estate property, net $ 9,131,717 $ 6,122,468 Cash and restricted cash 328,455 258,564 Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance 232,778 208,802 Debt and preferred equity investments, net 336,164 145,878 Other assets 683,481 248,474 Total assets $ 10,712,595 $ 6,984,186 Liabilities and members' equity Mortgages and other loans payable, net $ 6,453,966 $ 4,266,548 Deferred revenue/gain 356,414 209,095 Other liabilities 391,500 314,065 Members' equity 3,510,715 2,194,478 Total liabilities and members' equity $ 10,712,595 $ 6,984,186 Company's investments in unconsolidated joint ventures $ 1,890,186 $ 1,203,858 The combined statements of operations for the unconsolidated joint ventures, from acquisition date through the years ended December 31, 2016 , 2015 , and 2014 are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Total revenues $ 712,689 $ 576,845 $ 522,132 Operating expenses 126,913 106,613 82,436 Ground rent 14,924 14,083 9,898 Real estate taxes 111,673 89,734 64,217 Interest expense, net of interest income 197,741 199,126 178,743 Amortization of deferred financing costs 24,829 13,394 12,395 Transaction related costs 5,566 615 535 Depreciation and amortization 199,011 149,023 137,793 Total expenses $ 680,657 $ 572,588 $ 486,017 Loss on early extinguishment of debt (1,606 ) (1,089 ) (6,743 ) Net income before gain on sale $ 30,426 $ 3,168 $ 29,372 Company's equity in net income from unconsolidated joint ventures $ 11,874 $ 13,028 $ 26,537

Deferred Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs	Deferred Costs Deferred costs at December 31, 2016 and 2015 consisted of the following (in thousands): December 31, 2016 2015 Deferred leasing costs $ 468,971 $ 415,406 Less: accumulated amortization (201,371 ) (175,486 ) Deferred costs, net $ 267,600 $ 239,920

Mortgages and Other Loans Payab

Mortgages and Other Loans Payable	12 Months Ended
	Dec. 31, 2016
Mortgages and Other Loans Payable
Mortgages and Other Loans Payable	Mortgages and Other Loans Payable The first mortgages and other loans payable collateralized by the respective properties and assignment of leases at December 31, 2016 and 2015 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 31, 2016 December 31, 2015 Fixed Rate Debt: FHLBNY Facility (2) January 2017 1.03 % $ 105,000 $ — FHLBNY Facility (2) January 2017 0.80 % 100,000 — 485 Lexington Avenue (3) February 2017 5.61 % 450,000 450,000 762 Madison Avenue (4) February 2017 3.86 % 7,694 7,872 Unsecured Loan June 2018 4.81 % 16,000 16,000 One Madison Avenue May 2020 5.91 % 517,806 542,817 100 Church Street July 2022 4.68 % 221,446 225,099 919 Third Avenue (5) June 2023 5.12 % 500,000 500,000 420 Lexington Avenue October 2024 3.99 % 300,000 300,000 1515 Broadway March 2025 3.93 % 888,531 900,000 400 East 58th Street (6) November 2026 3.00 % 40,000 28,990 Landmark Square January 2027 5.05 % 100,000 79,562 Series J Preferred Units (7) April 2051 3.75 % 4,000 4,000 885 Third Avenue (8) 6.26 % 267,650 267,650 400 East 57th Street (9) — 67,644 11 Madison Avenue (10) — 1,400,000 388-390 Greenwich Street (11) — 1,004,000 500 West Putnam Avenue (12) — 22,376 Total fixed rate debt $ 3,518,127 $ 5,816,010 Floating Rate Debt: 719 Seventh Avenue February 2018 3.55 % $ 37,388 $ — 183, 187 Broadway & 5-7 Dey Street May 2018 3.16 % 58,000 40,000 Master Repurchase Agreement July 2018 3.04 % 184,642 253,424 1080 Amsterdam (13) November 2018 4.23 % 3,525 3,525 220 East 42nd Street October 2020 2.08 % 275,000 275,000 One Vanderbilt Avenue (14) September 2021 4.09 % 64,030 — FHLBNY Facility — 45,750 600 Lexington Avenue — 112,795 388-390 Greenwich Street (11) — 446,000 248-252 Bedford Avenue (15) — 29,000 Total floating rate debt $ 622,585 $ 1,205,494 Total fixed rate and floating rate debt $ 4,140,712 $ 7,021,504 Mortgages reclassed to liabilities related to assets held for sale (15) — (29,000 ) Total mortgages and other loans payable $ 4,140,712 $ 6,992,504 Deferred financing costs, net of amortization (66,882 ) (110,584 ) Total mortgages and other loans payable, net $ 4,073,830 $ 6,881,920 ____________________________________________________________________ (1) Effective weighted average interest rate for the year ended December 31, 2016 , taking into account interest rate hedges in effect during the period. (2) The facility was repaid in January 2017. (3) In January 2017, this loan was refinanced with a new $450.0 million mortgage with a fixed effective interest rate of 4.22% and a maturity date of February 2027. (4) In February 2017, the mortgage was repaid. (5) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan. (6) The loan carries a fixed interest rate of 3.00% for the first 5 years and is prepayable without penalty in year 5 . (7) In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million , 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000 per unit. The Series J Preferred Units are accounted for as debt because they can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement. (8) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and as a result, the property remains on our consolidated balance sheet until the criteria is met. The maturity date of the mortgage on the property, which was assumed by the buyer, is July 2017. (9) In October 2016, we closed on the sale of a 49.0% interest on 400 East 57th Street. This property is now classified as an unconsolidated joint venture. (10) In August 2016, we closed on the sale of a 40.0% interest on 11 Madison Avenue. This property is now classified as an unconsolidated joint venture. (11) In June 2016, we closed on the sale of 388-390 Greenwich Street. (12) In January 2016, the mortgage was repaid. (13) In January 2017, this loan was refinanced with a new $47.0 million facility with a maturity date of January 2027. (14) In September 2016, we closed on a $1.5 billion construction facility in connection with the development of One Vanderbilt Avenue. This facility bears interest at 350 basis points over 30-day LIBOR, with reductions based on meeting certain conditions, and has an initial five -year term with two one -year extension options. Advances under the loan are subject to incurred costs, funded equity, loan to value thresholds, and entering into construction contracts. (15) This property at 248-252 Bedford Avenue in Brooklyn, New York was sold in February 2016. At December 31, 2015, this property was held for sale and the related mortgage, net of deferred financing, net of amortization costs of $0.6 million , was included in liabilities related to assets held for sale. Federal Home Loan Bank of New York Facility The Company’s wholly-owned subsidiary, Belmont Insurance Company, or Belmont, a New York licensed captive insurance company, is a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Belmont may borrow funds from the FHLBNY in the form of secured advances. As of December 31, 2016 , we had $205.0 million in outstanding secured advances with a weighted average borrowing rate of 0.92% . On January 12, 2016, the Federal Housing Finance Agency, or FHFA, adopted a final regulation on Federal Home Loan Bank, or FHLB, membership. The rule excludes captive insurance entities from FHLB membership on a going-forward basis and provides termination rules for current captive insurance members. Belmont's membership was terminated on February 20, 2017. All funds borrowed from the FHLBNY were repaid in January 2017. Master Repurchase Agreement In July, 2016 we entered into a restated Master Repurchase Agreement, or MRA, which provides us with the ability to sell certain debt investments with a simultaneous agreement to repurchase the same at a certain date or on demand. The MRA has a maximum facility capacity of $300.0 million and bears interest ranging from 225 and 400 basis points over 30-day LIBOR depending on the pledged collateral. Since December 6, 2015, we have been required to pay monthly in arrears a 25 basis point fee on the excess of $150.0 million over the average daily balance during the period if the average daily balance is less than $150.0 million . We seek to mitigate risks associated with our repurchase agreement by managing the credit quality of our assets, early repayments, interest rate volatility, liquidity, and market value. The margin call provisions under our repurchase facility permit valuation adjustments based on capital markets activity, and are not limited to collateral-specific credit marks. To monitor credit risk associated with our debt investments, our asset management team regularly reviews our investment portfolio and is in contact with our borrowers in order to monitor the collateral and enforce our rights as necessary. The risk associated with potential margin calls is further mitigated by our ability to recollateralize the facility with additional assets from our portfolio of debt investments, our ability to satisfy margin calls with cash or cash equivalents and access to additional liquidity through the 2012 credit facility, as defined below. At December 31, 2016 and 2015 , the gross book value of the properties and debt and preferred equity investments collateralizing the mortgages and other loans payable, not including assets held for sale, was approximately $6.0 billion and $10.8 billion , respectively.

Corporate Indebtedness

Corporate Indebtedness	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Corporate Indebtedness	Corporate Indebtedness 2012 Credit Facility In August 2016, we entered into an amendment to the credit facility that was originally entered into by the Company in November 2012, referred to as the 2012 credit facility. As of December 31, 2016 , the 2012 credit facility, as amended, consisted of a $1.6 billion revolving credit facility and a $1.2 billion term loan, with a maturity date of March 29, 2019 and June 30, 2019, respectively. The revolving credit facility has an as-of-right extension to March 29, 2020. We also have an option, subject to customary conditions, to increase the capacity under the revolving credit facility to $3.0 billion at any time prior to the maturity date for the revolving credit facility without the consent of existing lenders, by obtaining additional commitments from our existing lenders and other financial institutions. As of December 31, 2016 , the 2012 credit facility bore interest at a spread over LIBOR ranging from (i) 87.5 basis points to 155 basis points for loans under the revolving credit facility and (ii) 95 basis points to 190 basis points for loans under the term loan facility, in each case based on the credit rating assigned to the senior unsecured long term indebtedness of ROP. At December 31, 2016 , the applicable spread was 125 basis points for the revolving credit facility and 140 basis points for the term loan facility. At December 31, 2016 , the effective interest rate was 1.78% for the revolving credit facility and 2.27% for the term loan facility. We are required to pay quarterly in arrears a 12.5 to 30 basis point facility fee on the total commitments under the revolving credit facility based on the credit rating assigned to the senior unsecured long term indebtedness of ROP. As of December 31, 2016 , the facility fee was 25 basis points. As of December 31, 2016 , we had $56.5 million of outstanding letters of credit, zero drawn under the revolving credit facility and $1.2 billion outstanding under the term loan facility, with total undrawn capacity of $1.5 billion under the 2012 credit facility. At December 31, 2016 and December 31, 2015 , the revolving credit facility had a carrying value of $(6.3) million , representing deferred financing costs presented within other liabilities, and $985.1 million , respectively, net of deferred financing costs. At December 31, 2016 and December 31, 2015 , the term loan facility had a carrying value of $1.2 billion and $929.5 million , respectively, net of deferred financing costs. The Company, the Operating Partnership and ROP are all borrowers jointly and severally obligated under the 2012 credit facility. None of our other subsidiaries are obligors under the 2012 credit facility. The 2012 credit facility includes certain restrictions and covenants (see Restrictive Covenants below). Senior Unsecured Notes The following table sets forth our senior unsecured notes and other related disclosures as of December 31, 2016 and 2015 , respectively, by scheduled maturity date (dollars in thousands): Issuance December 31, 2016 Unpaid Principal Balance December 31, 2016 Accreted Balance December 31, 2015 Accreted Balance Coupon Rate (1) Effective Rate Term (in Years) Maturity Date October 12, 2010 (2) $ 345,000 $ 334,077 $ 321,130 3.00 % 3.00 % 7 October 2017 August 5, 2011 (3) 250,000 249,880 249,810 5.00 % 5.00 % 7 August 2018 March 16, 2010 (3) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (3) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (3) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 March 26, 2007 (4) — — 10,008 March 31, 2006 (5) — — 255,296 $ 1,145,000 $ 1,133,957 $ 1,386,244 Deferred financing costs, net (5,642 ) (7,280 ) $ 1,145,000 $ 1,128,315 $ 1,378,964 ____________________________________________________________________ (1) Interest on the senior unsecured notes is payable semi-annually with principal and unpaid interest due on the scheduled maturity dates. (2) Issued by the Operating Partnership. Interest on these exchangeable notes is payable semi-annually on April 15 and October 15. The notes had an initial exchange rate representing an exchange price that was set at a 30.0% premium to the last reported sale price of SL Green's common stock on October 6, 2010, or $85.81 . The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 12.6478 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. As a result of meeting specified events (as defined in the Indenture Agreement), these notes became exchangeable commencing January 1, 2016 and will remain exchangeable through March 31, 2016. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of December 31, 2016 , $10.9 million remained to be amortized into the debt balance. (3) Issued by the Company, the Operating Partnership and ROP, as co-obligors. (4) Balance was repaid in September 2016. (5) Issued by ROP, balance was repaid in March 2016. Restrictive Covenants The terms of the 2012 credit facility, as amended, and certain of our senior unsecured notes include certain restrictions and covenants which may limit, among other things, our ability to pay dividends, make certain types of investments, incur additional indebtedness, incur liens and enter into negative pledge agreements and dispose of assets, and which require compliance with financial ratios relating to the maximum ratio of total indebtedness to total asset value, a minimum ratio of EBITDA to fixed charges, a maximum ratio of secured indebtedness to total asset value and a maximum ratio of unsecured indebtedness to unencumbered asset value. The dividend restriction referred to above provides that, we will not during any time when a default is continuing, make distributions with respect to common stock or other equity interests, except to enable the Company to continue to qualify as a REIT for Federal income tax purposes. As of December 31, 2016 and 2015 , we were in compliance with all such covenants. Junior Subordinated Deferrable Interest Debentures In June 2005, the Company and the Operating Partnership issued $100.0 million in unsecured trust preferred securities through a newly formed trust, SL Green Capital Trust I, or the Trust, which is a wholly-owned subsidiary of the Operating Partnership. The securities mature in 2035 and bear interest at a fixed rate of 5.61% for the first ten years ending July 2015. Thereafter, the interest rate will float at 125 basis points over the three-month LIBOR. Interest payments may be deferred for a period of up to eight consecutive quarters if the Operating Partnership exercises its right to defer such payments. The Trust preferred securities are redeemable at the option of the Operating Partnership, in whole or in part, with no prepayment premium. We do not consolidate the Trust even though it is a variable interest entity as we are not the primary beneficiary. Because the Trust is not consolidated, we have recorded the debt on our consolidated balance sheets and the related payments are classified as interest expense. Principal Maturities Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of December 31, 2016 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Amortization Principal Revolving Credit Facility Unsecured Term Loan Trust Preferred Securities Senior Unsecured Notes Total Joint Venture Debt 2017 $ 51,531 $ 930,329 $ — $ — $ — $ 345,000 $ 1,326,860 $ 574,327 2018 54,371 299,555 — — — 250,000 603,926 48,253 2019 58,916 — — 1,183,000 — — 1,241,916 555,545 2020 40,700 679,531 — — — 250,000 970,231 31,183 2021 29,666 64,030 — — — — 93,696 222,452 Thereafter 86,275 1,845,808 — — 100,000 300,000 2,332,083 1,311,022 $ 321,459 $ 3,819,253 $ — $ 1,183,000 $ 100,000 $ 1,145,000 $ 6,568,712 $ 2,742,782 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Year Ended December 31, 2016 2015 2014 Interest expense before capitalized interest $ 348,062 $ 357,926 $ 342,648 Interest capitalized (24,067 ) (31,108 ) (22,750 ) Interest income (2,796 ) (2,948 ) (2,498 ) Interest expense, net $ 321,199 $ 323,870 $ 317,400

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Cleaning/ Security/ Messenger and Restoration Services Alliance Building Services, or Alliance, and its affiliates are partially owned by Gary Green, a son of Stephen L. Green, the chairman of SL Green's board of directors, and provide services to certain properties owned by us. Alliance’s affiliates include First Quality Maintenance, L.P., or First Quality, Classic Security LLC, Bright Star Couriers LLC and Onyx Restoration Works, and provide cleaning, extermination, security, messenger, and restoration services, respectively. In addition, First Quality has the non-exclusive opportunity to provide cleaning and related services to individual tenants at our properties on a basis separately negotiated with any tenant seeking such additional services. The Service Corporation has entered into an arrangement with Alliance whereby it will receive a profit participation above a certain threshold for services provided by Alliance to certain tenants at certain buildings above the base services specified in their lease agreements. Income earned from profit participation, which is included in other income on the consolidated statements of operations, was $3.5 million , $3.8 million , and $3.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. We also recorded expenses, inclusive of capitalized expenses, of $23.4 million , $21.3 million , and $21.5 million the years ended December 31, 2016 , 2015 and 2014 , respectively, for these services (excluding services provided directly to tenants). Management Fees S.L. Green Management Corp., a consolidated entity, receives property management fees from an entity in which Stephen L. Green owns an interest. We received management fees from this entity of $0.7 million , $0.5 million and $0.4 million for the years ended December 31, 2016 , 2015 , and 2014 respectively. One Vanderbilt Co-Investment In December 2016, we entered into agreements with entities owned and controlled by Messrs. Holliday and Mathias, pursuant to which they agreed to make a co-investment with us in our One Vanderbilt development project. Pursuant to these agreements, Messrs. Holliday and Mathias agreed to purchase interests in the One Vanderbilt development project that will entitle them to receive approximately 2.50%-3.00% of the profit generated from this project in excess of capital contributions. 50% of these interests were purchased on December 31, 2016 and the remaining 50% are to be purchased on December 31, 2017. The aggregate purchase price for these interests is $2.4 million, which equals the fair market value of these interests as of the date the co-investment agreements were entered into as determined by an independent third party appraisal that we obtained. Messrs. Holliday and Mathias cannot monetize their interests until after stabilization of the property (50% within three years after stabilization and 100% three years or more after stabilization). In addition, the agreement calls for us to repurchase these interests in the event of a sale of One Vanderbilt or a transactional change of control of the Company. We also have the right to repurchase these interests on the seven-year anniversary of the stabilization of the project or upon the occurrence of certain separation events prior to the stabilization of the project relating to each of Messrs. Holliday’s and Mathias’s continued service with us. The price paid upon monetization of the interests will equal the liquidation value of the interests at the time, with the value of One Vanderbilt being based on its sale price, if applicable, or fair market value as determined by an independent third party appraiser. Other Amounts due from related parties at December 31, 2016 and 2015 consisted of the following (in thousands): December 31, 2016 2015 Due from joint ventures $ 1,240 $ 1,334 Other 14,616 9,316 Related party receivables $ 15,856 $ 10,650

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interests on the Company's Consolidated Financial Statements	Noncontrolling Interests on the Company's Consolidated Financial Statements Noncontrolling interests represent the common and preferred units of limited partnership interest in the Operating Partnership not held by the Company as well as third party equity interests in our other consolidated subsidiaries. Noncontrolling interests in the Operating Partnership are shown in the mezzanine equity while the noncontrolling interests in our other consolidated subsidiaries are shown in the equity section of the Company’s consolidated financial statements. Common Units of Limited Partnership Interest in the Operating Partnership As of December 31, 2016 and 2015 , the noncontrolling interest unit holders owned 4.16% , or 4,363,716 units, and 3.61% , or 3,745,766 units, of the Operating Partnership, respectively. At December 31, 2016 , 4,363,716 shares of SL Green's common stock were reserved for issuance upon the redemption of units of limited partnership interest of the Operating Partnership. Noncontrolling interests in the Operating Partnership is recorded at the greater of its cost basis or fair market value based on the closing stock price of SL Green's common stock at the end of the reporting period. Below is the rollforward analysis of the activity relating to the noncontrolling interests in the Operating Partnership as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Balance at beginning of period $ 424,206 $ 469,524 Distributions (12,671 ) (9,710 ) Issuance of common units 78,495 30,506 Redemption of common units (31,805 ) (55,697 ) Net income 10,136 10,565 Accumulated other comprehensive income allocation 1,299 (67 ) Fair value adjustment 4,222 (20,915 ) Balance at end of period $ 473,882 $ 424,206 Preferred Units of Limited Partnership Interest in the Operating Partnership The Operating Partnership has 1,902,000 4.50% Series G Preferred Units of limited partnership interest, or the Series G Preferred Units outstanding, with a liquidation preference of $25.00 per unit, which were issued in January 2012 in conjunction with an acquisition. The Series G Preferred unitholders receive annual dividends of $1.125 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series G Preferred Units are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $88.50 . The common units of limited partnership interest in the Operating Partnership may be redeemed in exchange for SL Green's common stock on a 1 -to-1 basis. The Series G Preferred Units also provide the holder with the right to require the Operating Partnership to repurchase the Series G Preferred Units for cash before January 31, 2022. The Operating Partnership has 60 Series F Preferred Units outstanding with a mandatory liquidation preference of $1,000.00 per unit. The Operating Partnership has authorized up to 700,000 3.50% Series K Preferred Units of limited partnership interest, or the Series K Preferred Units, with a liquidation preference of $25.00 per unit. In August 2014, the Company issued 563,954 Series K Preferred Units in conjunction with an acquisition. The Series K Preferred unitholders receive annual dividends of $0.875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series K Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $134.67 . The Operating Partnership has authorized up to 500,000 4.00% Series L Preferred Units of limited partnership interest, or the Series L Preferred Units, with a liquidation preference of $25.00 per unit. In August 2014, the Company issued 378,634 Series L Preferred Units in conjunction with an acquisition. The Series L Preferred unitholders receive annual dividends of $1.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series L Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 1,600,000 3.75% Series M Preferred Units of limited partnership interest, or the Series M Preferred Units, with a liquidation preference of $25.00 per unit. In February 2015, the Company issued 1,600,000 Series M Preferred Units in conjunction with the acquisition of ownership interests in and relating to certain residential and retail real estate properties. The Series M Preferred unitholders receive annual dividends of $0.9375 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series M Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 552,303 3.00% Series N Preferred Units of limited partnership interest, or the Series N Preferred Units, with a liquidation preference of $25.00 per unit. In June 2015, the Company issued 552,303 Series N Preferred Units in conjunction with an acquisition. The Series N Preferred unitholders receive annual dividends of $0.75 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series N Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized an aggregate of one 6.25% Series O Preferred Unit of limited partnership interest, or the Series O Preferred Unit. In June 2015, the Company issued the Series O Preferred Unit in connection with an acquisition. The Operating Partnership has authorized up to 200,000 4.00% Series P Preferred Units of limited partnership interest, or the Series P Preferred Units, with a liquidation preference of $25.00 per unit. In July 2015, the Company issued 200,000 Series P Preferred Units in conjunction with an acquisition. The Series P Preferred unitholders receive annual dividends of $1.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series P Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 268,000 3.50% Series Q Preferred Units of limited partnership interest, or the Series Q Preferred Units, with a liquidation preference of $25.00 per unit. In July 2015, the Company issued 268,000 Series Q Preferred Units in conjunction with an acquisition. The Series Q Preferred unitholders receive annual dividends of $0.875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series Q Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $148.95 . The Operating Partnership has authorized up to 400,000 3.50% Series R Preferred Units of limited partnership interest, or the Series R Preferred Units, with a liquidation preference of $25.00 per unit. In August 2015, the Company issued 400,000 Series R Preferred Units in conjunction with an acquisition. The Series R Preferred unitholders receive annual dividends of $0.875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series R Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $154.89 . The Operating Partnership has authorized up to 1,077,280 4.00% Series S Preferred Units of limited partnership interest, or the Series S Preferred Units, with a liquidation preference of $25.00 per unit. In August 2015, the Company issued 1,077,280 Series S Preferred Units in conjunction with an acquisition. The Series S Preferred unitholders receive annual dividends of $1.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series S Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 230,000 2.75% Series T Preferred Units of limited partnership interest, or the Series T Preferred Units, with a liquidation preference of $25.00 per unit. In March 2016, the Company issued 230,000 Series T Preferred Units in conjunction with an acquisition. The Series T Preferred unitholders receive annual dividends of $0.6875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series T Preferred Units can be redeemed at any time at par, at the option of the unitholder, either for cash or are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $119.02 . The Operating Partnership has authorized up to 680,000 4.50% Series U Preferred Units of limited partnership interest, or the Series U Preferred Units, with a liquidation preference of $25.00 per unit. In March 2016, the Company issued 680,000 Series U Preferred Units in conjunction with an acquisition. The Series U Preferred unitholders initially receive annual dividends of $1.125 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The annual dividend is subject to reduction upon the occurence of certain circumstances set forth in the terms of the Series U Preferred Units. The minimum annual dividend is $0.75 per unit. The Series U Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. T hrough a consolidated subsidiary, we have authorized up to 109,161 3.5% Series A Preferred Units of limited partnership interest, or the Subsidiary Series A Preferred Units, with a liquidation preference of $1,000.00 per unit. In August 2015, the Company issued 109,161 Subsidiary Series A Preferred Units in conjunction with an acquisition. The Subsidiary Series A Preferred unitholders receive annual dividends of $35.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Subsidiary Series A Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible on a one-for-one basis, into the Series B Preferred Units of limited partnership interest, or the Subsidiary Series B Preferred Units. The Subsidiary Series B Preferred Units can be converted at any time, at the option of the unitholder, into a number of common stock equal to 6.71348 shares of common stock for each Subsidiary Series B Preferred Unit. As of December 31, 2016 , no Subsidiary Series B Preferred Units have been issued. Below is the rollforward analysis of the activity relating to the preferred units in the Operating Partnership as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Balance at beginning of period $ 282,516 $ 71,115 Issuance of preferred units 22,793 211,601 Redemption of preferred units (3,299 ) (200 ) Balance at end of period $ 302,010 $ 282,516

Stockholders' Equity of the Com

Stockholders' Equity of the Company	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Stockholders' Equity of the Company	Stockholders’ Equity of the Company Common Stock Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2016 , 100,562,349 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of December 31, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership. In June 2014, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014 , we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. During the year ended December 31, 2015 , we sold 895,956 shares of our common stock for aggregate net proceeds of $113.4 million comprising the remaining balance of this ATM Program. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 895,956 units of limited partnership interest of the Operating Partnership. In March 2015, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015 we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the year ended December 31, 2016 . Perpetual Preferred Stock We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units. Dividend Reinvestment and Stock Purchase Plan In February 2015, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the year ended December 31, 2016 , 2015, and 2014, respectively (in thousands): Year Ended December 31, 2016 2015 2014 Common Stock Shares Issued 2,687 775,760 608 Dividend reinvestments/stock purchases under the DRSPP $ 277 $ 99,555 $ 64 Earnings per Share SL Green's earnings per share for the years ended December 31, 2016 , 2015 , and 2014 are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic Earnings: Income attributable to SL Green common stockholders $ 234,946 $ 269,132 $ 503,104 Effect of Dilutive Securities: Redemption of units to common shares 10,136 10,565 18,467 Diluted Earnings: Income attributable to SL Green common stockholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic Shares: Weighted average common stock outstanding 100,185 99,345 95,774 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,323 3,899 3,514 Stock-based compensation plans 373 490 408 Diluted weighted average common stock outstanding 104,881 103,734 99,696 SL Green has excluded 774,782 , 263,991 and 737,361 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2016 , 2015 , and 2014 respectively, as they were anti-dilutive.

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity
Partners' Capital of the Operating Partnership	Stockholders’ Equity of the Company Common Stock Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2016 , 100,562,349 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of December 31, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership. In June 2014, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014 , we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. During the year ended December 31, 2015 , we sold 895,956 shares of our common stock for aggregate net proceeds of $113.4 million comprising the remaining balance of this ATM Program. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 895,956 units of limited partnership interest of the Operating Partnership. In March 2015, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015 we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the year ended December 31, 2016 . Perpetual Preferred Stock We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units. Dividend Reinvestment and Stock Purchase Plan In February 2015, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the year ended December 31, 2016 , 2015, and 2014, respectively (in thousands): Year Ended December 31, 2016 2015 2014 Common Stock Shares Issued 2,687 775,760 608 Dividend reinvestments/stock purchases under the DRSPP $ 277 $ 99,555 $ 64 Earnings per Share SL Green's earnings per share for the years ended December 31, 2016 , 2015 , and 2014 are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic Earnings: Income attributable to SL Green common stockholders $ 234,946 $ 269,132 $ 503,104 Effect of Dilutive Securities: Redemption of units to common shares 10,136 10,565 18,467 Diluted Earnings: Income attributable to SL Green common stockholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic Shares: Weighted average common stock outstanding 100,185 99,345 95,774 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,323 3,899 3,514 Stock-based compensation plans 373 490 408 Diluted weighted average common stock outstanding 104,881 103,734 99,696 SL Green has excluded 774,782 , 263,991 and 737,361 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2016 , 2015 , and 2014 respectively, as they were anti-dilutive.
SL Green Operating Partnership
Stockholders' Equity
Partners' Capital of the Operating Partnership	Partners' Capital of the Operating Partnership The Company is the sole general partner of the Operating Partnership and at December 31, 2016 owned 100,562,349 general and limited partnership interests in the Operating Partnership and 9,200,000 Series I Preferred Units. Partnership interests in the Operating Partnership are denominated as “common units of limited partnership interest” (also referred to as “OP Units”) or “preferred units of limited partnership interest” (also referred to as “Preferred Units”). All references to OP Units and Preferred Units outstanding exclude such units held by the Company. A holder of an OP Unit may present such OP Unit to the Operating Partnership for redemption at any time (subject to restrictions agreed upon at the issuance of OP Units to particular holders that may restrict such right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Operating Partnership must redeem such OP Unit in exchange for the cash equal to the then value of a share of common stock of the Company, except that the Company may, at its election, in lieu of cash redemption, acquire such OP Unit for one share of common stock. Because the number of shares of common stock outstanding at all times equals the number of OP Units that the Company owns, one share of common stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of common stock. Each series of Preferred Units makes a distribution that is set in accordance with an amendment to the partnership agreement of the Operating Partnership. Preferred Units may also be convertible into OP Units at the election of the holder thereof or the Company, subject to the terms of such Preferred Units. Net income (loss) allocated to the preferred unitholders and common unitholders reflects their pro rata share of net income (loss) and distributions. Limited Partner Units As of December 31, 2016 , limited partners other than SL Green owned 4.16% , or 4,363,716 common units, of the Operating Partnership. Preferred Units Preferred units not owned by SL Green are further described in Note 11, “Noncontrolling Interests on the Company’s Consolidated Financial Statements - Preferred Units of Limited Partnership Interest in the Operating Partnership.” Earnings per Unit The Operating Partnership's earnings per unit for the years ended December 31, 2016 , 2015 , and 2014 respectively are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic and Diluted Earnings: Income attributable to SLGOP common unitholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic units: Weighted average common units outstanding 104,508 103,244 99,288 Effect of Dilutive Securities: Stock-based compensation plans 373 490 408 Diluted weighted average common units outstanding 104,881 103,734 99,696 The Operating Partnership has excluded 774,782 , 263,991 , and 737,361 common unit equivalents from the diluted units outstanding for the years ended December 31, 2016 , 2015 , and 2014 respectively, as they were anti-dilutive.

Share-based Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	Share-based Compensation We have stock-based employee and director compensation plans. Our employees are compensated through the Operating Partnership. Under each plan, whenever the Company issues common or preferred stock, the Operating Partnership issues an equivalent number of units of limited partnership interest of a corresponding class to the Company. Fourth Amended and Restated 2005 Stock Option and Incentive Plan The Fourth Amended and Restated 2005 Stock Option and Incentive Plan, or the 2005 Plan, was approved by the Company's board of directors in April 2016 and its stockholders in June 2016 at the Company's annual meeting of stockholders. The 2005 Plan authorizes the issuance of stock options, stock appreciation rights, unrestricted and restricted stock, phantom shares, dividend equivalent rights, cash-based awards and other equity-based awards. Subject to adjustments upon certain corporate transactions or events, awards with respect to up to a maximum of 27,030,000 fungible units may be granted under the 2005 Plan. Currently, different types of awards count against the limit on the number of fungible units differently, with (1) full-value awards (i.e., those that deliver the full value of the award upon vesting, such as restricted stock) granted after the effective date of the Fourth Amendment 2005 Plan counting as 3.74 Fungible Units per share subject to such awards, (2) stock options, stock appreciation rights and other awards that do not deliver full value and expire five years from the date of grant counting as 0.73 fungible units per share subject to such awards, and (3) all other awards (e.g., ten -year stock options) counting as 1.0 fungible units per share subject to such awards. Awards granted under the 2005 Plan prior to the approval of the fourth amendment and restatement in June 2016 continue to count against the fungible unit limit based on the ratios that were in effect at the time such awards were granted, which may be different than the current ratios. As a result, depending on the types of awards issued, the 2005 Plan may result in the issuance of more or less than 27,030,000 shares. If a stock option or other award granted under the 2005 Plan expires or terminates, the common stock subject to any portion of the award that expires or terminates without having been exercised or paid, as the case may be, will again become available for the issuance of additional awards. Shares of SL Green's common stock distributed under the 2005 Plan may be treasury shares or authorized but unissued shares. Currently, unless the 2005 Plan has been previously terminated by the Company's board of directors, new awards may be granted under the 2005 Plan until June 2, 2026, which is the tenth anniversary of the date that the 2005 Plan was most recently approved by the Company's stockholders. As of December 31, 2016 , 9.5 million fungible units were available for issuance under the 2005 Plan after reserving for shares underlying outstanding restricted stock units, phantom stock units granted pursuant to our Non-Employee Directors' Deferral Program and LTIP Units, including, among others, outstanding LTIP Units issued under our 2014 Outperformance Plan. Options are granted under the plan with an exercise price at the fair market value of the Company's common stock on the date of grant and, subject to employment, generally expire five or ten years from the date of grant, are not transferable other than on death, and generally vest in one to five years commencing one year from the date of grant. We have also granted Class O LTIP Units, which are a class of LTIP Units in the Operating Partnership structured to provide economics similar to those of stock options. Class O LTIP Units, once vested, may be converted, at the election of the holder, into a number of common units of the Operating Partnership per Class O LTIP Unit determined by the increase in value of a share of the Company’s common stock at the time of conversion over a participation threshold, which equals the fair market value of a share of the Company’s common stock at the time of grant. Class O LTIP Units are entitled to distributions, subject to vesting, equal per unit to 10% of the per unit distributions paid with respect to the common units of the Operating Partnership. The fair value of each stock option or Class O LTIP Unit granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information with the following weighted average assumptions for grants during the years ended December 31, 2016 , 2015 , and 2014 . 2016 2015 2014 Dividend yield 2.37 % 1.97 % 1.60 % Expected life 3.7 years 3.6 years 3.6 years Risk-free interest rate 1.57 % 1.43 % 1.29 % Expected stock price volatility 26.76 % 32.34 % 33.97 % A summary of the status of the Company's stock options as of December 31, 2016 , 2015 , and 2014 and changes during the years ended December 31, 2016 , 2015 , and 2014 are as follows: 2016 2015 2014 Options Outstanding Weighted Average Exercise Price Options Outstanding Weighted Average Exercise Price Options Weighted Balance at beginning of year $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 $ 1,765,034 $ 83.24 Granted 445,100 105.86 389,836 112.54 102,050 119.12 Exercised (192,875 ) 76.90 (217,438 ) 74.69 (348,156 ) 72.76 Lapsed or cancelled (110,019 ) 123.86 (40,117 ) 98.61 (56,202 ) 90.03 Balance at end of year $ 1,737,213 $ 98.44 $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 Options exercisable at end of year 748,617 $ 87.72 589,055 $ 89.85 $ 428,951 $ 90.32 Weighted average fair value of options granted during the year $ 8,363,036 $ 9,522,613 $ 2,841,678 All options were granted with strike prices ranging from $ 20.67 to $ 137.18 . The remaining weighted average contractual life of the options outstanding was 3.7 years and the remaining average contractual life of the options exercisable was 2.9 years. During the years ended December 31, 2016 , 2015 , and 2014 , we recognized compensation expense for these options of $8.9 million, $8.0 million, and $8.1 million , respectively. As of December 31, 2016 , there was $ 13.3 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average period of 2.1 years. Stock-based Compensation Effective January 1, 1999, the Company implemented a deferred compensation plan, or the Deferred Plan, where shares issued under the Deferred Plan were granted to certain employees, including our executives and vesting will occur annually upon the completion of a service period or our meeting established financial performance criteria. Annual vesting occurs at rates ranging from 15% to 35% once performance criteria are reached. A summary of the Company's restricted stock as of December 31, 2016 , 2015 , and 2014 and charges during the years ended December 31, 2016 , 2015 , and 2014 are as follows: 2016 2015 2014 Balance at beginning of year 3,137,881 3,000,979 2,994,197 Granted 98,800 143,053 9,550 Cancelled (34,650 ) (6,151 ) (2,768 ) Balance at end of year 3,202,031 3,137,881 3,000,979 Vested during the year 83,822 87,081 75,043 Compensation expense recorded $ 7,153,966 $ 7,540,747 $ 9,658,019 Weighted average fair value of restricted stock granted during the year $ 10,650,077 $ 16,061,201 $ 1,141,675 The fair value of restricted stock that vested during the years ended December 31, 2016 , 2015 , and 2014 was $7.6 million , $7.4 million and $5.5 million , respectively. As of December 31, 2016 , there was $21.0 million of total unrecognized compensation cost related to restricted stock, which is expected to be recognized over a weighted average period of 2.7 years . For the years ended December 31, 2016 , 2015 , and 2014 , $6.0 million , $6.5 million , and $6.8 million , respectively, was capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options. We granted LTIP Units, which include bonus, time-based and performance based awards, with a fair value of $34.9 million and $25.4 million as of December 31, 2016 and 2015 , respectively. The grant date fair value of the LTIP Unit awards was calculated in accordance with ASC 718. A third party consultant determined the fair value of the LTIP Units to have a discount from SL Green's common stock price. The discount was calculated by considering the inherent uncertainty that the LTIP Units will reach parity with other common partnership units and the illiquidity due to transfer restrictions. As of December 31, 2016 , there was $5.7 million of total unrecognized compensation expense related to the time-based and performance based awards, which is expected to be recognized over a weighted average period of 1.9 years. During the years ended December 31, 2016 , 2015 , and 2014 , we recorded compensation expense related to bonus, time-based and performance based awards of $26.5 million $30.2 million, and $ 31.4 million, respectively. 2010 Notional Unit Long-Term Compensation Plan In December 2009, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2010 Notional Unit Long-Term Compensation Program, or the 2010 Long-Term Compensation Plan. The 2010 Long-Term Compensation Plan is a long-term incentive compensation plan pursuant to which award recipients could earn, in the aggregate, from $15.0 million up to $75.0 million of LTIP Units in the Operating Partnership based on the Company's stock price appreciation over three years beginning on December 1, 2009; provided that, if maximum performance had been achieved, $25.0 million of awards could be earned at any time after the beginning of the second year and an additional $25.0 million of awards could be earned at any time after the beginning of the third year. In order to achieve maximum performance under the 2010 Long-Term Compensation Plan, the Company's aggregate stock price appreciation during the performance period had to equal or exceed 50% . The compensation committee determined that maximum performance had been achieved at or shortly after the beginning of each of the second and third years of the performance period and for the full performance period and, accordingly, 385,583 LTIP Units, 327,416 LTIP Units and 327,416 LTIP Units were earned under the 2010 Long-Term Compensation Plan in December 2010, 2011 and 2012, respectively. Substantially in accordance with the original terms of the program, 50% of these LTIP Units vested on December 17, 2012 (accelerated from the original January 1, 2013 vesting date), 25% of these LTIP Units vested on December 11, 2013 (accelerated from the original January 1, 2014 vesting date) and the remainder vested on January 1, 2015 based on continued employment. In accordance with the terms of the 2010 Long-Term Compensation Plan, distributions were not paid on any LTIP Units until they were earned, at which time we paid all distributions that would have been paid on the earned LTIP Units since the beginning of the performance period. The cost of the 2010 Long-Term Compensation Plan ( $31.7 million , subject to forfeitures) was amortized into earnings through the final vesting period of January 1, 2015. We recorded compensation expense of $ 2.7 million during the year ended December 31, 2014 related to the 2010 Long-Term Compensation Plan. 2011 Outperformance Plan In August 2011, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2011 Outperformance Plan, or the 2011 Outperformance Plan. Participants in the 2011 Outperformance Plan could earn, in the aggregate, up to $85.0 million of LTIP Units in the Operating Partnership based on our total return to stockholders for the three-year period beginning September 1, 2011. Under the 2011 Outperformance Plan, participants were entitled to share in a "performance pool" comprised of LTIP Units with a value equal to 10% of the amount by which our total return to stockholders during the three -year period exceeded a cumulative total return to stockholders of 25% , subject to the maximum of $85.0 million of LTIP Units; provided that if maximum performance was achieved, one-third of each award could be earned at any time after the beginning of the second year and an additional one-third of each award could be earned at any time after the beginning of the third year. LTIP Units earned under the 2011 Outperformance Plan are subject to vesting requirements, with 50% of any awards earned vested on August 31, 2014 and the remaining 50% vesting on August 31, 2015, based on continued employment with us through such dates. Participants were not entitled to distributions with respect to LTIP Units granted under the 2011 Outperformance Plan unless and until they were earned. For LTIP Units that were earned, each participant was also entitled to the distributions that would have been paid had the number of earned LTIP Units been issued at the beginning of the performance period, with such distributions being paid in the form of additional LTIP Units. Thereafter, distributions are to be paid currently with respect to all earned LTIP Units, whether vested or unvested. In June 2014, the compensation committee determined that maximum performance had been achieved during the third year of the performance period and, accordingly, 560,908 LTIP Units, representing two-thirds of each award, were earned, subject to vesting, under the 2011 Outperformance Plan. In September 2014, the compensation committee determined that maximum performance had been achieved for the full three -year performance period and, accordingly, 280,454 LTIP units, representing the final third of each award, were earned, subject to vesting, under the 2011 Outperformance Plan. The cost of the 2011 Outperformance Plan ( $26.7 million , subject to forfeitures) was amortized into earnings through the final vesting period. We recorded no compensation expense during the year ended December 31, 2016 , and recorded compensation expense of $4.5 million , and $8.6 million during the years ended December 31, 2015 and 2014 , respectively, related to the 2011 Outperformance Plan. 2014 Outperformance Plan In August 2014, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2014 Outperformance Plan, or the 2014 Outperformance Plan. Participants in the 2014 Outperformance Plan may earn, in the aggregate, up to 610,000 LTIP Units in our Operating Partnership based on our total return to stockholders for the three -year period beginning September 1, 2014. Under the 2014 Outperformance Plan, two-thirds of the LTIP Units may be earned based on the Company’s absolute total return to stockholders and one-third of the LTIP Units may be earned based on relative total return to stockholders compared to the constituents of the MSCI REIT Index. Awards earned based on absolute total return to stockholders will be determined independently of awards earned based on relative total return to stockholders. In the event the Company’s performance reaches either threshold before the end of the three -year performance period, a pro-rata portion of the maximum award may be earned. For each component, if the Company’s performance reaches the maximum threshold beginning with the 19th month of the performance period, participants will earn one-third of the maximum award that may be earned for that component. If the Company’s performance reaches the maximum threshold during the third year of the performance period for a component, participants will earn two-thirds (or an additional one-third) of the maximum award that may be earned for that component. LTIP Units earned under the 2014 Outperformance Plan will be subject to continued vesting requirements, with 50% of any awards earned vesting on August 31, 2017 and the remaining 50% vesting on August 31, 2018, subject to continued employment with us through such dates. Participants will not be entitled to distributions with respect to LTIP Units granted under the 2014 Outperformance Plan unless and until they are earned. If LTIP Units are earned, each participant will also be entitled to the distributions that would have been paid had the number of earned LTIP Units been issued at the beginning of the performance period, with such distributions being paid in the form of cash or additional LTIP Units. Thereafter, distributions will be paid currently with respect to all earned LTIP Units, whether vested or unvested. The cost of the 2014 Outperformance Plan ( $27.9 million , subject to forfeitures), based on the portion of the 2014 Outperformance Plan granted as of December 31, 2016 , will be amortized into earnings through the final vesting period. We recorded compensation expense of $8.4 million , $5.9 million and $0.2 million during the years ended December 31, 2016 , 2015 , and 2014 , respectively, related to the 2014 Outperformance Plan. Deferred Compensation Plan for Directors Under our Non-Employee Director's Deferral Program, which commenced July 2004, the Company's non-employee directors may elect to defer up to 100% of their annual retainer fee, chairman fees, meeting fees and annual stock grant. Unless otherwise elected by a participant, fees deferred under the program shall be credited in the form of phantom stock units. The program provides that a director's phantom stock units generally will be settled in an equal number of shares of common stock upon the earlier of (i) the January 1 coincident with or the next following such director's termination of service from the Board of Directors or (ii) a change in control by us, as defined by the program. Phantom stock units are credited to each non-employee director quarterly using the closing price of SL Green's common stock on the first business day of the respective quarter. Each participating non-employee director is also credited with dividend equivalents or phantom stock units based on the dividend rate for each quarter, which are either paid in cash currently or credited to the director’s account as additional phantom stock units. During the year ended December 31, 2016 , 9,022 phantom stock units were earned and 9,279 shares of common stock were issued to our board of directors. We recorded compensation expense of $2.1 million during the year ended December 31, 2016 related to the Deferred Compensation Plan. As of December 31, 2016 , there were 89,790 phantom stock units outstanding pursuant to our Non-Employee Director's Deferral Program. Employee Stock Purchase Plan In 2007, the Company's board of directors adopted the 2008 Employee Stock Purchase Plan, or ESPP, to encourage our employees to increase their efforts to make our business more successful by providing equity-based incentives to eligible employees. The ESPP is intended to qualify as an "employee stock purchase plan" under Section 423 of the Code, and has been adopted by the board to enable our eligible employees to purchase the Company's shares of common stock through payroll deductions. The ESPP became effective on January 1, 2008 with a maximum of 500,000 shares of the common stock available for issuance, subject to adjustment upon a merger, reorganization, stock split or other similar corporate change. The Company filed a registration statement on Form S-8 with the SEC with respect to the ESPP. The common stock is offered for purchase through a series of successive offering periods. Each offering period will be three months in duration and will begin on the first day of each calendar quarter, with the first offering period having commenced on January 1, 2008. The ESPP provides for eligible employees to purchase the common stock at a purchase price equal to 85% of the lesser of (1) the market value of the common stock on the first day of the offering period or (2) the market value of the common stock on the last day of the offering period. The ESPP was approved by our stockholders at our 2008 annual meeting of stockholders. As of December 31, 2016 , 95,448 shares of SL Green's common stock had been issued under the ESPP.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company/Operating Partnership	Stockholders’ Equity of the Company Common Stock Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2016 , 100,562,349 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of December 31, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership. In June 2014, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014 , we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. During the year ended December 31, 2015 , we sold 895,956 shares of our common stock for aggregate net proceeds of $113.4 million comprising the remaining balance of this ATM Program. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 895,956 units of limited partnership interest of the Operating Partnership. In March 2015, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015 we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the year ended December 31, 2016 . Perpetual Preferred Stock We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units. Dividend Reinvestment and Stock Purchase Plan In February 2015, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the year ended December 31, 2016 , 2015, and 2014, respectively (in thousands): Year Ended December 31, 2016 2015 2014 Common Stock Shares Issued 2,687 775,760 608 Dividend reinvestments/stock purchases under the DRSPP $ 277 $ 99,555 $ 64 Earnings per Share SL Green's earnings per share for the years ended December 31, 2016 , 2015 , and 2014 are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic Earnings: Income attributable to SL Green common stockholders $ 234,946 $ 269,132 $ 503,104 Effect of Dilutive Securities: Redemption of units to common shares 10,136 10,565 18,467 Diluted Earnings: Income attributable to SL Green common stockholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic Shares: Weighted average common stock outstanding 100,185 99,345 95,774 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,323 3,899 3,514 Stock-based compensation plans 373 490 408 Diluted weighted average common stock outstanding 104,881 103,734 99,696 SL Green has excluded 774,782 , 263,991 and 737,361 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2016 , 2015 , and 2014 respectively, as they were anti-dilutive.
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company/Operating Partnership	Accumulated Other Comprehensive Income (Loss) The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2016 , 2015 and 2014 (in thousands): Net unrealized (loss) gain on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized (loss) gain on derivative instruments ( 2 ) Unrealized gain (loss) on marketable securities Total Balance at December 31, 2013 $ (15,125 ) $ (4,870 ) $ 4,784 $ (15,211 ) Other comprehensive (loss) income before reclassifications (576 ) 2,847 (2,692 ) (421 ) Amounts reclassified from accumulated other comprehensive income 6,203 1,928 521 8,652 Balance at December 31, 2014 (9,498 ) (95 ) 2,613 (6,980 ) Other comprehensive loss before reclassifications (11,143 ) (1,714 ) (610 ) (13,467 ) Amounts reclassified from accumulated other comprehensive income 10,481 1,217 — 11,698 Balance at December 31, 2015 (10,160 ) (592 ) 2,003 (8,749 ) Other comprehensive income before reclassifications 13,534 1,160 3,517 18,211 Amounts reclassified from accumulated other comprehensive income 9,222 3,453 — 12,675 Balance at December 31, 2016 $ 12,596 $ 4,021 $ 5,520 $ 22,137 ____________________________________________________________________ (1) Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of operations. As of December 31, 2016 and 2015 , the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive income (loss) relating to net unrealized loss on derivative instrument, was $7.1 million and $9.7 million , respectively. (2) Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of operations.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We are required to disclose fair value information with regard to our financial instruments, whether or not recognized in the consolidated balance sheets, for which it is practical to estimate fair value. The FASB guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. We measure and/or disclose the estimated fair value of financial assets and liabilities based on a hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity and the reporting entity’s own assumptions about market participant assumptions. This hierarchy consists of three broad levels: Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date; Level 2 - inputs other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly; and Level 3 - unobservable inputs for the asset or liability that are used when little or no market data is available. We follow this hierarchy for our assets and liabilities measured at fair value on a recurring and nonrecurring basis. In instances in which the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level of input that is significant to the fair value measurement in its entirety. Our assessment of the significance of the particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2016 and 2015 (in thousands): December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 85,110 $ 48,315 $ 36,795 $ — Interest rate cap and swap agreements (included in other assets) $ 21,090 $ — $ 21,090 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 1 $ — $ 1 $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 45,138 $ 4,704 $ 40,434 $ — Interest rate cap and swap agreements (included in other assets) $ 204 $ — $ 204 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 10,776 $ — $ 10,776 $ — We determine other than temporary impairment in real estate investments and debt and preferred equity investments, including intangibles utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, which are classified as Level 3 inputs. The marketable securities classified as Level 1 were derived from quoted prices in active markets. The valuation technique used to measure the fair value of the marketable securities classified as Level 2 were valued based on quoted market prices or model driven valuations using the significant inputs derived from or corroborated by observable market data. Marketable securities in an unrealized loss position are not considered to be other than temporarily impaired. We do not intend to sell these securities and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases. The fair value of derivative instruments is based on current market data received from financial sources that trade such instruments and are based on prevailing market data and derived from third party proprietary models based on well-recognized financial principles and reasonable estimates about relevant future market conditions, which are classified as Level 2 inputs. The financial assets and liabilities that are not measured at fair value on our consolidated balance sheets include cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued expenses, debt and preferred equity investments, mortgages and other loans payable and other secured and unsecured debt. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, and accounts payable and accrued expenses reported in our consolidated balance sheets approximates fair value due to the short term nature of these instruments. The fair value of debt and preferred equity investments, which is classified as Level 3, is estimated by discounting the future cash flows using current interest rates at which similar loans with the same maturities would be made to borrowers with similar credit ratings. The fair value of borrowings, which is classified as Level 3, is estimated by discounting the contractual cash flows of each debt to their present value using adjusted market interest rates, which is provided by a third-party specialist. The following table provides the carrying value and fair value of these financial instruments as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,640,412 (2) $ 1,670,020 (2) Fixed rate debt $ 5,452,084 $ 5,722,494 $ 7,232,254 $ 7,591,388 Variable rate debt (3) 1,105,585 1,110,110 3,202,494 3,179,186 $ 6,557,669 $ 6,832,604 $ 10,434,748 $ 10,770,574 ____________________________________________________________________ (1) Amounts exclude net deferred financing costs. (2) At December 31, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.6 billion and $1.8 billion . At December 31, 2015 , debt and preferred equity investments had an estimated fair value ranging between $1.7 billion and $1.8 billion . (3) Includes the $29.0 million mortgage at 248-252 Bedford Avenue that is included in liabilities related to assets held for sale on the consolidated balance sheet at December 31, 2015 . Disclosure about fair value of financial instruments was based on pertinent information available to us as of December 31, 2016 and 2015 . Although we are not aware of any factors that would significantly affect the reasonable fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and current estimates of fair value may differ significantly from the amounts presented herein.

Financial Instruments_ Derivati

Financial Instruments: Derivatives and Hedging	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments: Derivatives and Hedging	Financial Instruments: Derivatives and Hedging In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collar and floors, to manage, or hedge interest rate risk. We hedge our exposure to variability in future cash flows for forecasted transactions in addition to anticipated future interest payments on existing debt. We recognize all derivatives on the balance sheets at fair value. Derivatives that are not hedges are adjusted to fair value through earnings. If a derivative is a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will either be offset against the change in fair value of the hedge asset, liability, or firm commitment through earnings, or recognized in other comprehensive income until the hedged item is recognized in earnings. The ineffective portion of a derivative's change in fair value will be immediately recognized in earnings. Reported net income and equity may increase or decrease prospectively, depending on future levels of interest rates and other variables affecting the fair values of derivative instruments and hedged items, but will have no effect on cash flows. Currently, all of our designated derivative instruments are effective hedging instruments. The following table summarizes the notional value at inception and fair value of our consolidated derivative financial instruments at December 31, 2016 based on Level 2 information. The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks (amounts in thousands). Notional Value Strike Rate Effective Date Expiration Date Balance Sheet Location Fair Value Interest Rate Swap $ 200,000 0.938 % October 2014 December 2017 Other Assets $ 11 Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Assets 5 Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Assets 5 Interest Rate Swap 14,409 0.500 % January 2015 January 2017 Other Assets 2 Interest Rate Swap 8,018 0.852 % February 2015 February 2017 Other Liabilities (1 ) Interest Rate Cap 137,500 4.000 % September 2015 September 2017 Other Assets — Interest Rate Cap 1,450,000 4.750 % May 2016 May 2017 Other Assets — Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Assets 10,293 Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Assets 4,963 Interest Rate Cap 23,199 4.500 % October 2016 October 2017 Other Assets — Interest Rate Swap 5,000 2.160 % December 2016 December 2026 Other Assets 77 Interest Rate Swap 225,000 2.185 % January 2017 January 2027 Other Assets 3,223 Interest Rate Swap 25,000 2.185 % January 2017 January 2027 Other Assets 358 Interest Rate Swap 150,000 2.183 % January 2017 January 2027 Other Assets 2,153 $ 21,089 During the years ended December 31, 2016 , 2015 , and 2014 , we recorded a gain on the changes in the fair value of $472,790 , $15,000 , and $61,000 , respectively, which is included in interest expense on the consolidated statements of operations. The Company has agreements with each of its derivative counterparties that contain a provision where if the Company either defaults or is capable of being declared in default on any of its indebtedness, then the Company could also be declared in default on its derivative obligations. As of December 31, 2016 , the fair value of derivatives in a net liability position including accrued interest but excluding any adjustment for nonperformance risk related to these agreements was $0.1 million . As of December 31, 2016 , the Company has not posted any collateral related to these agreements and was not in breach of any agreement provisions. If the Company had breached any of these provisions, it could have been required to settle its obligations under the agreements at their aggregate termination value of $0.1 million at December 31, 2016 . Gains and losses on terminated hedges are included in accumulated other comprehensive loss, and are recognized into earnings over the term of the related mortgage obligation. Over time, the realized and unrealized gains and losses held in accumulated other comprehensive loss will be reclassified into earnings as an adjustment to interest expense in the same periods in which the hedged interest payments affect earnings. We estimate that $2.2 million of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense and $1.2 million of the portion related to our share of joint venture accumulated other comprehensive loss will be reclassified into equity in net income from unconsolidated joint ventures within the next 12 months. The following table presents the effect of our derivative financial instruments and our share of our joint ventures' derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the years ended December 31, 2016 , 2015 , and 2014 , respectively (in thousands): Amount of (Loss) Gain Recognized in Other Comprehensive Loss (Effective Portion) Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location of (Loss) or Gain Recognized in Income on Derivative Amount of (Loss) or Gain Recognized into Income (Ineffective Portion) Year Ended Year Ended Year Ended Derivative 2016 2015 2014 2016 2015 2014 2016 2015 2014 Interest Rate Swaps/Caps $ 14,616 $ (11,607 ) $ (703 ) Interest expense $ 9,521 $ 10,892 $ 6,431 Interest expense $ (28 ) $ (422 ) $ 4 Share of unconsolidated joint ventures' derivative instruments 2,012 (1,779 ) 2,916 Equity in net income from unconsolidated joint ventures 1,981 1,265 1,999 Equity in net income from unconsolidated joint ventures 785 (19 ) — $ 16,628 $ (13,386 ) $ 2,213 $ 11,502 $ 12,157 $ 8,430 $ 757 $ (441 ) $ 4

Rental Income

Rental Income	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Rental Income	Rental Income The Operating Partnership is the lessor and the sublessor to tenants under operating leases with expiration dates ranging from January 1, 2017 to 2064. The minimum rental amounts due under the leases are generally either subject to scheduled fixed increases or adjustments. The leases generally also require that the tenants reimburse us for increases in certain operating costs and real estate taxes above their base year costs. Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2016 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands): Consolidated Properties Unconsolidated Properties 2017 $ 1,271,232 $ 198,304 2018 1,256,047 203,934 2019 1,161,772 195,888 2020 1,120,476 190,139 2021 976,638 184,367 Thereafter 8,062,838 1,389,446 $ 13,849,003 $ 2,362,078

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	Benefit Plans The building employees are covered by multi-employer defined benefit pension plans and post-retirement health and welfare plans. We participate in the Building Service 32BJ, or Union, Pension Plan and Health Plan. The Pension Plan is a multi-employer, non-contributory defined benefit pension plan that was established under the terms of collective bargaining agreements between the Service Employees International Union, Local 32BJ, the Realty Advisory Board on Labor Relations, Inc. and certain other employees. This Pension Plan is administered by a joint board of trustees consisting of union trustees and employer trustees and operates under employer identification number 13-1879376. The Pension Plan year runs from July 1 to June 30. Employers contribute to the Pension Plan at a fixed rate on behalf of each covered employee. Separate actuarial information regarding such pension plans is not made available to the contributing employers by the union administrators or trustees, since the plans do not maintain separate records for each reporting unit. However, on September 30, 2014, and September 28, 2015, and September 28, 2016, the actuary certified that for the plan years beginning July 1, 2014, July 1, 2015, and July 1, 2016, respectively, the Pension Plan was in critical status under the Pension Protection Act of 2006. The Pension Plan trustees adopted a rehabilitation plan consistent with this requirement. No surcharges have been paid to the Pension Plan as of December 31, 2016 . For the the Pension Plan years ended June 30, 2016, 2015 , and 2014 , the plan received contributions from employers totaling $249.5 million, $221.9 million, and $226.7 million . Our contributions to the Pension Plan represent less than 5.0% of total contributions to the plan. The Health Plan was established under the terms of collective bargaining agreements between the Union, the Realty Advisory Board on Labor Relations, Inc. and certain other employers. The Health Plan provides health and other benefits to eligible participants employed in the building service industry who are covered under collective bargaining agreements, or other written agreements, with the Union. The Health Plan is administered by a Board of Trustees with equal representation by the employers and the Union and operates under employer identification number 13-2928869. The Health Plan receives contributions in accordance with collective bargaining agreements or participation agreements. Generally, these agreements provide that the employers contribute to the Health Plan at a fixed rate on behalf of each covered employee. For the Health Plan years ended, June 30, 2016, 2015 , and 2014 , the plan received contributions from employers totaling $1.2 billion , $1.1 billion and $1.0 billion million, respectively. Our contributions to the Health Plan represent less than 5.0% of total contributions to the plan. Contributions we made to the multi-employer plans for the years ended December 31, 2016 , 2015 and 2014 are included in the table below (in thousands): Benefit Plan 2016 2015 2014 Pension Plan $ 3,979 $ 2,732 $ 2,807 Health Plan 11,530 8,736 8,470 Other plans 1,583 5,716 5,838 Total plan contributions $ 17,092 $ 17,184 $ 17,115 401(K) Plan In August 1997, we implemented a 401(K) Savings/Retirement Plan, or the 401(K) Plan, to cover eligible employees of ours, and any designated affiliate. The 401(K) Plan permits eligible employees to defer up to 15% of their annual compensation, subject to certain limitations imposed by the Code. The employees' elective deferrals are immediately vested and non-forfeitable upon contribution to the 401(K) Plan. During 2000, we amended our 401(K) Plan to include a matching contribution, subject to ERISA limitations, equal to 50% of the first 4% of annual compensation deferred by an employee. During 2003, we amended our 401(K) Plan to provide for discretionary matching contributions only. For 2016 , 2015 and 2014 , a matching contribution equal to 50% of the first 6% of annual compensation was made. For the year ended December 31, 2016 , we made matching contribution of $566,000 . For each of the years ended 2015 and 2014 , we made matching contributions o

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of December 31, 2016 , the Company and the Operating Partnership were not involved in any material litigation nor, to management's knowledge, was any material litigation threatened against us or our portfolio which if adversely determined could have a material adverse impact on us. Environmental Matters Our management believes that the properties are in compliance in all material respects with applicable Federal, state and local ordinances and regulations regarding environmental issues. Management is not aware of any environmental liability that it believes would have a materially adverse impact on our financial position, results of operations or cash flows. Management is unaware of any instances in which it would incur significant environmental cost if any of our properties were sold. Employment Agreements We have entered into employment agreements with certain executives, which expire between December 2017 and January 2020. The minimum cash-based compensation, including base salary and guaranteed bonus payments, associated with these employment agreements total $5.2 million for 2017. In addition these employment agreements provide for deferred compensation awards based on our stock price and which were valued at $1.6 million on the grant date. The value of these awards may change based on fluctuations in our stock price. Insurance We maintain “all-risk” property and rental value coverage (including coverage regarding the perils of flood, earthquake and terrorism, excluding nuclear, biological, chemical, and radiological terrorism ("NBCR")), within three property insurance programs and liability insurance. Management believes the policy specifications and insured limits are appropriate given the relative risk of loss, the cost of the coverage, and industry practice. Separate property and liability coverage may be purchased on a stand-alone basis for certain assets, such as the development of One Vanderbilt. On January 12, 2015, the Terrorism Risk Insurance Program Reauthorization and Extension Act of 2007 ("TRIPRA") (formerly the Terrorism Risk Insurance Act) was reauthorized until December 31, 2020 pursuant to the Terrorism Insurance Program Reauthorization and Extension Act of 2015. The TRIPRA extends the federal Terrorism Insurance Program that requires insurance companies to offer terrorism coverage and provides for compensation for insured losses resulting from acts of certified terrorism, subject to the current program trigger of $120.0 million , which will increase by $20.0 million per annum, commencing December 31, 2015 (Trigger). Coinsurance under TRIPRA is 16% , increasing 1% per annum, as of December 31, 2015 (Coinsurance). There are no assurances TRIPRA will be further extended. Our wholly-owned taxable REIT subsidiary, Belmont Insurance Company, or Belmont, acts as a captive insurance company and as one of the elements of our overall insurance program. Belmont was formed in an effort, among other reasons, to stabilize to some extent the impact of insurance market fluctuations. Belmont is licensed by New York State as a direct insurer of Terrorism and NBCR Terrorism, and a reinsurer with respect to portions of our General Liability, Environmental Liability, Flood, Professional Liability, Employment Practices Liability and D&O coverage. Belmont purchases reinsurance for its Coinsurance and is backstopped by the Federal government for the balance of its terrorism limit for certified acts of terrorism above the Trigger. We purchase direct, third party terrorism insurance up to the Trigger for certified acts of terrorism. Belmont is backstopped by the Federal government for certified acts of NBCR terrorism above the Trigger and subject to its Coinsurance, however does not reinsure its NBCR Coinsurance requirement. There is no coverage for a NBCR terrorism act if covered industry losses are below the Trigger. As long as we own Belmont, we are responsible for its liquidity and capital resources, and the accounts of Belmont are part of our consolidated financial statements. If we experience a loss and Belmont is required to pay a claim under our insurance policies, we would ultimately record the loss to the extent of Belmont's required payment. Therefore, certain insurance coverage provided by Belmont should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. Our debt instruments, consisting of mortgage loans secured by our properties (which are generally non-recourse to us), mezzanine loans, ground leases, our 2012 credit facility, senior unsecured notes and other corporate obligations, contain customary covenants requiring us to maintain insurance. Although we believe that we currently maintain sufficient insurance coverage to satisfy these obligations, there is no assurance that in the future we will be able to procure coverage at a reasonable cost. In such instances, there can be no assurance that the lenders or ground lessors under these instruments will not take the position that a total or partial exclusion from “all-risk” insurance coverage for losses due to, for example, terrorist acts is a breach of these debt and ground lease instruments allowing the lenders or ground lessors to declare an event of default and accelerate repayment of debt or recapture of ground lease positions. In addition, if lenders require greater coverage that we are unable to obtain at commercially reasonable rates, we may incur substantially higher insurance premiums or our ability to finance our properties and expand our portfolio may be adversely impacted. Furthermore, with respect to certain of our properties, including properties held by joint ventures, or subject to triple net leases, insurance coverage is obtained by a third-party and we do not control the coverage. While we may have agreements with such third parties to maintain adequate coverage and we monitor these policies, such coverage ultimately may not be maintained or adequately cover our risk of loss. We may have less protection than with respect to the properties where we obtain coverage directly. Although we consider our insurance coverage to be appropriate, in the event of a major catastrophe, we may not have sufficient coverage to replace certain properties. Belmont had loss reserves of $6.3 million and $6.4 million as of December 31, 2016 and 2015 , respectively. Capital and Ground Leases Arrangements In 2015, we entered into a ground lease for the land and building located at 30 East 40th Street with a lease term ending in August 2114. Based on our evaluation of the arrangement under ASC 840, land was estimated to be approximately 63.6% of the fair market value of the property. The portion attributable to land was classified as operating lease and the remainder as a capital lease in the amount of $20.0 million . The property located at 420 Lexington Avenue operates under a ground lease ( $10.9 million of ground rent annually through December 2019, $11.2 million of ground rent annually through December 2029, and $12.3 million annually afterwards, subject to a one-time adjustment based on 6% of the fair value of the land) with an expiration date of 2050 and two options to renew for an additional 35 years. The property located at 1080 Amsterdam Avenue operates under a ground and capital lease with an expiration date of 2111 ( $41.6 million total over the lease term attributed to ground rent). Land was estimated to be 40.0% of the fair market value of the property, which was classified as an operating lease. The remainder was classified as a capital lease. The property located at 711 Third Avenue operates under an operating sub-lease, which expires in 2083. The ground rent was reset in July 2011. Following the reset, we are responsible for ground rent payments of $5.25 million annually through July 2016 and then $5.5 million annually thereafter on the 50% portion of the fee that we do not own. The property located at 461 Fifth Avenue operates under a ground lease ( $2.1 million of ground rent annually) with an expiration date of 2027 and two options to renew for an additional 21 years each, followed by a third option for 15 years. We also have an option to purchase the fee position for a fixed price on a specific date. The property located at 625 Madison Avenue operates under a ground lease ( $4.6 million of ground rent annually) with an expiration date of 2022 and two options to renew for an additional 23 years. The property located at 1185 Avenue of the Americas operates under a ground lease ( $6.9 million of ground rent annually) with an expiration of 2043 and an option to renew for an additional 23 years. The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of December 31, 2016 (in thousands): Capital lease Non-cancellable operating leases 2017 $ 2,387 $ 31,049 2018 2,387 31,049 2019 2,411 31,066 2020 2,620 31,436 2021 2,794 31,628 Thereafter 822,688 732,724 Total minimum lease payments $ 835,287 $ 888,952 Less amount representing interest (793,155 ) Capital lease obligations $ 42,132

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information The Company is a REIT engaged in all aspects of property ownership and management including investment, leasing operations, capital improvements, development, redevelopment, financing, construction and maintenance in the New York Metropolitan area and have two reportable segments, real estate and debt and preferred equity. We evaluate real estate performance and allocate resources based on earnings contribution to income from continuing operations. The primary sources of revenue are generated from tenant rents and escalations and reimbursement revenue. Real estate property operating expenses consist primarily of security, maintenance, utility costs, real estate taxes and ground rent expense (at certain applicable properties). See Note 5, "Debt and Preferred Equity Investments," for additional details on our debt and preferred equity investments. Selected results of operations for the years ended December 31, 2016 , 2015 , and 2014 , and selected asset information as of December 31, 2016 and 2015 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues Years ended: December 31, 2016 $ 1,629,919 $ 234,062 $ 1,863,981 December 31, 2015 1,465,881 196,948 1,662,829 December 31, 2014 1,320,777 199,201 1,519,978 Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and (loss) gain on sale of marketable securities Years ended: December 31, 2016 $ (203,988 ) $ 211,244 $ 7,256 December 31, 2015 (78,681 ) 168,970 90,289 December 31, 2014 31,805 169,695 201,500 Total assets As of: December 31, 2016 $ 13,868,085 $ 1,989,702 $ 15,857,787 December 31, 2015 17,765,854 1,961,792 19,727,646 Income from continuing operations represents total revenues less total expenses for the real estate segment and total investment income less allocated interest expense for the debt and preferred equity segment. Interest costs for the debt and preferred equity segment includes actual costs incurred for investments collateralizing the MRA. Interest is imputed on the remaining investments using our corporate borrowing cost. We also allocate loan loss reserves, net of recoveries, and transaction related costs to the debt and preferred equity segment. We do not allocate marketing, general and administrative expenses to the debt and preferred equity segment since the use of personnel and resources is dependent on transaction volume between the two segments and varies period over period. In addition, we base performance on the individual segments prior to allocating marketing, general and administrative expenses. For the years ended, December 31, 2016, 2015, and 2014 marketing, general and administrative expenses totaled $99.8 million , $94.9 million , and $92.5 million respectively. All other expenses, except interest, relate entirely to the real estate assets. There were no transactions between the above two segments. The table below reconciles income from continuing operations to net income for the years ended December 31, 2016 , 2015 , and 2014 (in thousands): Year ended December 31, 2016 2015 2014 Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and loss (gain) on sale of marketable securities $ 7,256 $ 90,289 $ 201,500 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 44,009 15,844 123,253 Purchase price fair value adjustment — 40,078 67,446 Gain on sale of real estate, net 238,116 175,974 — Depreciable real estate reserves (10,387 ) (19,226 ) — Loss on early extinguishment of debt — (49 ) (32,365 ) (Loss) gain on sale of investment in marketable securities (83 ) — 3,895 Income from continuing operations 278,911 302,910 363,729 Net income from discontinued operations — 427 19,075 Gain on sale of discontinued operations — 14,122 163,059 Net income $ 278,911 $ 317,459 $ 545,863

Quarterly Financial Data of the

Quarterly Financial Data of the Company (unaudited)	12 Months Ended
	Dec. 31, 2016
SL Green Realty Corp
Condensed Income Statements, Captions [Line Items]
Quarterly Financial Data of the Company/Operating Partnership (unaudited)	Quarterly Financial Data of the Company (unaudited) Summarized quarterly financial data for the years ended December 31, 2016 and 2015 , which is reflective of the reclassification of the properties sold or held for sale during 2015 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts): 2016 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 374,242 $ 416,681 $ 617,614 $ 455,444 Income (loss) from continuing operations before equity in net (loss) income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves and loss on sale of marketable securities $ 26,278 $ 46,689 $ (76,304 ) $ (1,281 ) Equity in net (loss) income from unconsolidated joint ventures (95 ) (3,968 ) 5,841 10,096 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 421 225 33,448 9,915 Gain on sale of real estate 27,366 397 196,580 13,773 Depreciable real estate reserves — — (10,387 ) — Loss on the sale of investment in marketable securities — — (83 ) — Noncontrolling interests and preferred unit distributions (6,217 ) (5,353 ) (11,901 ) (5,544 ) Net income attributable to SL Green 47,753 37,990 137,194 26,959 Perpetual preferred stock dividends (3,737 ) (3,738 ) (3,737 ) (3,738 ) Net income attributable to SL Green common stockholders $ 44,016 $ 34,252 $ 133,457 $ 23,221 Net income attributable to common stockholders per common share—basic $ 0.44 $ 0.34 $ 1.33 $ 0.23 Net income attributable to common stockholders per common share—diluted $ 0.44 $ 0.34 $ 1.33 $ 0.23 2015 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 425,390 $ 432,066 $ 409,074 $ 396,299 Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 54,591 $ 17,367 $ (32,942 ) $ 38,245 Equity in net income from unconsolidated joint ventures 2,377 3,627 2,994 4,030 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (206 ) 15,281 769 — Purchase price fair value adjustment 40,078 — — — Gain on sale of real estate 16,270 159,704 — — Depreciable real estate reserves — (19,226 ) — — Loss on early extinguishment of debt — — — (49 ) Net income from discontinued operations — — — 427 Gain on sale of discontinued operations 1,139 — — 12,983 Noncontrolling interests and preferred unit distributions (9,208 ) (9,357 ) (6,189 ) (8,621 ) Net income (loss) attributable to SL Green 105,041 167,396 (35,368 ) 47,015 Perpetual preferred stock dividends (3,738 ) (3,738 ) (3,738 ) (3,738 ) Net income (loss) attributable to SL Green common stockholders $ 101,303 $ 163,658 $ (39,106 ) $ 43,277 Net income (loss) attributable to common stockholders per common share—basic $ 1.02 $ 1.64 $ (0.39 ) $ 0.44 Net income (loss) attributable to common stockholders per common share—diluted $ 1.01 $ 1.64 $ (0.39 ) $ 0.44

Quarterly Financial Data of t35

Quarterly Financial Data of the Operating Partnership (unaudited)	12 Months Ended
	Dec. 31, 2016
SL Green Operating Partnership
Condensed Income Statements, Captions [Line Items]
Quarterly Financial Data of the Company/Operating Partnership (unaudited)	Quarterly Financial Data of the Operating Partnership (unaudited) Summarized quarterly financial data for the years ended December 31, 2016 and 2015 , which is reflective of the reclassification of the properties sold or held for sale during 2015 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts): 2016 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 374,242 $ 416,681 $ 617,614 $ 455,444 Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 26,278 $ 46,689 $ (76,304 ) $ (1,281 ) Equity in net income (loss) from unconsolidated joint ventures (95 ) (3,968 ) 5,841 10,096 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 421 225 33,448 9,915 Gain on sale of real estate 27,366 397 196,580 13,773 Depreciable real estate reserves — — (10,387 ) — Loss on the sale of investment in marketable securities — (83 ) Noncontrolling interests and preferred unit distributions (4,252 ) (3,690 ) (6,315 ) (4,622 ) Net income attributable to SLGOP 49,718 39,653 142,780 27,881 Perpetual preferred units distributions (3,737 ) (3,738 ) (3,737 ) (3,738 ) Net income attributable to SLGOP common unitholders $ 45,981 $ 35,915 $ 139,043 $ 24,143 Net income attributable to common unitholders per common unit—basic $ 0.44 $ 0.34 $ 1.33 $ 0.23 Net income attributable to common unitholders per common unit—diluted $ 0.44 $ 0.34 $ 1.33 $ 0.23 2015 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 425,390 $ 432,066 $ 409,074 $ 396,299 Income (loss) 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, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 54,591 $ 17,367 $ (32,942 ) $ 38,245 Equity in net income from unconsolidated joint ventures 2,377 3,627 2,994 4,030 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (206 ) 15,281 769 — Purchase price fair value adjustment 40,078 — — — Gain on sale of real estate 16,270 159,704 — — Depreciable real estate reserves — (19,226 ) — — Loss on early extinguishment of debt — — — (49 ) Net income from discontinued operations — — — 427 Gain on sale of discontinued operations 1,139 — — 12,983 Noncontrolling interests and preferred unit distributions (5,277 ) (2,890 ) (7,766 ) (6,878 ) Net income (loss) attributable to SLGOP 108,972 173,863 (36,945 ) 48,758 Perpetual preferred distributions (3,738 ) (3,738 ) (3,738 ) (3,738 ) Net income attributable to SLGOP common unitholders $ 105,234 $ 170,125 $ (40,683 ) $ 45,020 Net income attributable to common unitholders per common unit—basic $ 1.02 $ 1.64 $ (0.39 ) $ 0.44 Net income attributable to common unitholders per common unit—diluted $ 1.01 $ 1.64 $ (0.39 ) $ 0.44

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts	Column A Column B Column C Column D Column E Description Balance at Beginning of Year Additions Charged Against Operations Uncollectible Accounts Written-off/Recovery Balance at End of Year Year Ended December 31, 2016 Tenant and other receivables—allowance $ 17,618 $ 10,630 $ (11,656 ) $ 16,592 Deferred rent receivable—allowance $ 21,730 $ 13,620 $ (10,147 ) $ 25,203 Year Ended December 31, 2015 Tenant and other receivables—allowance $ 18,068 $ 8,139 $ (8,589 ) $ 17,618 Deferred rent receivable—allowance $ 27,411 $ 2,789 $ (8,470 ) $ 21,730 Year Ended December 31, 2014 Tenant receivables—allowance $ 17,325 $ 13,533 $ (12,790 ) $ 18,068 Deferred rent receivable—allowance $ 30,333 $ 4,140 $ (7,062 ) $ 27,411

Schedule III - Real Estate And

Schedule III - Real Estate And Accumulated Depreciation	12 Months Ended
	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III - Real Estate And Accumulated Depreciation	Column A Column B Column C Initial Cost Column D Cost Capitalized Subsequent To Acquisition Column E Gross Amount at Which Carried at Close of Period Column F Column G Column H Column I Description Encumbrances Land Building & Improvements Land Building & Improvements Land Building & Improvements Total Accumulated Depreciation Date of Construction Date Acquired Life on Which Depreciation is Computed 420 Lexington Ave(1) 300,000 — 107,832 — 239,911 — 347,743 347,743 139,418 1927 3/1998 Various 711 Third Avenue(1)(2) — 19,844 42,499 — 57,916 19,844 100,415 120,259 34,418 1955 5/1998 Various 555 W. 57th Street(1) — 18,846 78,704 — 59,564 18,846 138,268 157,114 58,187 1971 1/1999 Various 220 East 42nd Street(1) 275,000 50,373 203,727 635 85,907 51,008 289,634 340,642 90,730 1929 2/2003 Various 461 Fifth Avenue(1) — — 62,695 — 10,723 — 73,418 73,418 26,105 1988 10/2003 Various 750 Third Avenue(1) — 51,093 205,972 — 39,436 51,093 245,408 296,501 85,282 1958 7/2004 Various 625 Madison Ave(1) — — 246,673 — 41,937 — 288,610 288,610 97,690 1956 10/2004 Various 485 Lexington Avenue(1) 450,000 77,517 326,825 765 94,646 78,282 421,471 499,753 155,321 1956 12/2004 Various 609 Fifth Avenue(1) — 36,677 145,954 — 8,270 36,677 154,224 190,901 41,993 1925 6/2006 Various 810 Seventh Avenue(1) — 114,077 476,386 — 65,985 114,077 542,371 656,448 145,216 1970 1/2007 Various 919 Third Avenue(1)(3) 500,000 223,529 1,033,198 35,410 42,038 258,939 1,075,236 1,334,175 274,778 1970 1/2007 Various 1185 Avenue of the Americas(1) — — 728,213 — 39,403 — 767,616 767,616 221,415 1969 1/2007 Various 1350 Avenue of the Americas(1) — 91,038 380,744 — 37,736 91,038 418,480 509,518 114,264 1966 1/2007 Various 1100 King Street— 1-7 International Drive(4) — 49,392 104,376 (24,004 ) 23,954 25,388 128,330 153,718 35,062 1983/1986 1/2007 Various 520 White Plains Road(4) — 6,324 26,096 — 6,602 6,324 32,698 39,022 9,158 1979 1/2007 Various 115-117 Stevens Avenue(4) — 5,933 23,826 — 5,390 5,933 29,216 35,149 7,622 1984 1/2007 Various 100 Summit Lake Drive(4) — 10,526 43,109 — 8,476 10,526 51,585 62,111 15,149 1988 1/2007 Various 200 Summit Lake Drive(4) — 11,183 47,906 — 10,448 11,183 58,354 69,537 16,543 1990 1/2007 Various 500 Summit Lake Drive(4) — 9,777 39,048 — 5,290 9,777 44,338 54,115 11,672 1986 1/2007 Various 360 Hamilton Avenue(4) — 29,497 118,250 — 13,844 29,497 132,094 161,591 35,784 2000 1/2007 Various 1-6 Landmark Square(5) 100,000 50,947 195,167 — 45,253 50,947 240,420 291,367 61,359 1973-1984 1/2007 Various 7 Landmark Square(5) — 2,088 7,748 (367 ) 670 1,721 8,418 10,139 1,032 2007 1/2007 Various 680 Washington Boulevard(3)(5) — 11,696 45,364 — 10,126 11,696 55,490 67,186 14,462 1989 1/2007 Various 750 Washington Boulevard(3)(5) — 16,916 68,849 — 8,350 16,916 77,199 94,115 19,727 1989 1/2007 Various 1010 Washington Boulevard(5) — 7,747 30,423 — 6,598 7,747 37,021 44,768 9,722 1988 1/2007 Various 400 Summit Lake Drive(4) — 38,889 1 285 2 39,174 3 39,177 — --- 1/2007 N/A 1055 Washington Boulevard(5) — 13,516 53,228 — 7,559 13,516 60,787 74,303 15,655 1987 6/2007 Various 1 Madison Avenue(1) 517,806 172,641 654,394 905 15,381 173,546 669,775 843,321 158,913 1960 8/2007 Various 125 Chubb Way(6) — 5,884 25,958 — 25,556 5,884 51,514 57,398 9,170 2008 1/2008 Various 100 Church Street(1) 221,446 32,494 79,996 2,500 90,141 34,994 170,137 205,131 40,466 1959 1/2010 Various 125 Park Avenue(1) — 120,900 189,714 — 68,264 120,900 257,978 378,878 54,736 1923 10/2010 Various 885 Third Avenue(1) 267,650 131,766 — 110,771 — 242,537 — 242,537 — --- 12/2010 N/A Williamsburg(7) — 3,677 14,708 2,523 (4,550 ) 6,200 10,158 16,358 1,604 2010 12/2010 Various 1515 Broadway(1) 888,531 462,700 707,938 1,145 136,457 463,845 844,395 1,308,240 137,847 1972 4/2011 Various 110 East 42nd Street(1) — 34,000 46,411 2,354 21,634 36,354 68,045 104,399 15,275 1921 5/2011 Various Column A Column B Column C Initial Cost Column D Cost Capitalized Subsequent To Acquisition Column E Gross Amount at Which Carried at Close of Period Column F Column G Column H Column I Description Encumbrances Land Building & Improvements Land Building & Improvements Land Building & Improvements Total Accumulated Depreciation Date of Construction Date Acquired Life on Which Depreciation is Computed 400 East 58th Street(1)(8) 40,000 17,549 30,916 — 7,048 17,549 37,964 55,513 4,199 1929 1/2012 Various 752 Madison Avenue(1) — 282,415 7,131 1,871 10 284,286 7,141 291,427 1,068 1996/2012 1/2012 Various 762 Madison Avenue(1)(8) 7,694 6,153 10,461 — 90 6,153 10,551 16,704 1,359 1910 1/2012 Various 19-21 East 65th Street(1)(8) — — 7,389 — 148 — 7,537 7,537 947 1928-1940 1/2012 Various 304 Park Avenue(1) — 54,189 75,619 300 11,792 54,489 87,411 141,900 13,322 1930 6/2012 Various 635 Sixth Avenue(1) — 24,180 37,158 163 50,189 24,343 87,347 111,690 4,428 1902 9/2012 Various 641 Sixth Avenue(1) — 45,668 67,316 308 3,076 45,976 70,392 116,368 9,339 1902 9/2012 Various 1080 Amsterdam(1)(9) 3,525 — 27,445 — 20,521 — 47,966 47,966 2,950 1932 10/2012 Various 16 Court Street(7) — 19,217 63,210 — 16,092 19,217 79,302 98,519 10,366 1927-1928 4/2013 Various 315 West 33rd Street (1) — 195,834 164,429 — 8,919 195,834 173,348 369,182 15,160 2000-2001 11/2013 Various 562 Fifth Avenue(1) — 57,052 10,487 — 1,213 57,052 11,700 68,752 2,735 1909/1920/1921 11/2013 Various 719 Seventh Avenue(1)(10) 37,388 41,850 — 1,288 27,265 43,138 27,265 70,403 — 1927 7/2014 Various 115 Spring Street(1) — 11,078 44,799 — 1,686 11,078 46,485 57,563 2,918 1900 7/2014 Various 635 Madison(1) — 205,632 15,805 — — 205,632 15,805 221,437 910 9/2014 N/A 102 Greene Street(1) — 8,215 26,717 35 482 8,250 27,199 35,449 888 1910 11/2014 Various 1640 Flatbush Avenue(7) — 6,226 501 — 127 6,226 628 6,854 22 1966 3/2015 Various One Vanderbilt (1)(11) 64,030 80,069 116,557 — 191,441 80,069 307,998 388,067 — N/A 6/2001 - 11/2011 Various Upper East Side Residential (1)(12) — 48,152 — — — 48,152 — 48,152 — 1930 6/2015 Various 110 Greene Street (1)(8) — 45,120 215,470 — 3,985 45,120 219,455 264,575 9,459 1910 7/2015 Various 187 Broadway (1) 8,400 7,600 9,412 (266 ) (262 ) 7,334 9,150 16,484 3,145 1969 8/2015 Various 5-7 Dey Street (1) 31,600 13,400 34,175 (468 ) (5 ) 12,932 34,170 47,102 11,704 1921 8/2015 Various 30 East 40th Street (1) — 4,650 20,000 2 1,031 4,652 21,031 25,683 295 1927 8/2015 Various 600 Lexington Avenue (1)(13) — 81,670 182,447 (2,166 ) (1,607 ) 79,504 180,840 260,344 6,443 1983 12/2015 Various 183 Broadway(1) 18,000 5,799 23,431 385 715 6,184 24,146 30,330 4,591 1920 3/2016 Various Other(14) — 2,134 7,922 (3 ) 20 2,131 7,942 10,073 2,671 Various Total $ 3,731,070 $ 3,175,339 $ 7,760,729 $ 134,371 $ 1,672,893 $ 3,309,710 $ 9,433,622 $ 12,743,332 $ 2,264,694 ______________________________________________________________________ (1) Property located in New York, New York. (2) We own a 50.0% interest in this property. (3) We own a 51.0% interest in this property. (4) Property located in Westchester County, New York. (5) Property located in Connecticut. (6) Property located in New Jersey. (7) Property located in Brooklyn, New York. (8) We own a 90.0% interest in this property. (9) We own a 92.5% interest in this property. (10) We own a 75.0% interest in this property. (11) Properties at 317 Madison Avenue, 331 Madison Avenue and 51 East 42nd Street were demolished in preparation of the development site for the One Vanderbilt project. (12) We own a 95.1% interest in this property. (13) In May 2010 we acquired a 55.0% interest in this property for $193.0 million . In December 2015 we acquired the additional 45.0% interest in this property, thereby consolidating full ownership of the property. The December 2015 transaction valued the consolidated interests at $277.3 million . (14) Other includes tenant improvements of eEmerge, capitalized interest and corporate improvements. The changes in real estate for the years ended December 31, 2016 , 2015 and 2014 are as follows (in thousands): 2016 2015 2014 Balance at beginning of year $ 16,681,602 $ 14,069,141 $ 12,333,780 Property acquisitions 29,230 3,064,137 2,428,259 Improvements 426,060 396,555 379,295 Retirements/disposals/deconsolidation (4,393,560 ) (848,231 ) (1,072,193 ) Balance at end of year $ 12,743,332 $ 16,681,602 $ 14,069,141 The aggregate cost of land, buildings and improvements, before depreciation, for Federal income tax purposes at December 31, 2016 was $9.2 billion (unaudited). The changes in accumulated depreciation, exclusive of amounts relating to equipment, autos, and furniture and fixtures, for the years ended December 31, 2016 , 2015 and 2014 are as follows (in thousands): 2016 2015 2014 Balance at beginning of year $ 2,060,706 $ 1,905,165 $ 1,646,240 Depreciation for year 353,502 480,523 307,823 Retirements/disposals/deconsolidation (149,514 ) (324,982 ) (48,898 ) Balance at end of year $ 2,264,694 $ 2,060,706 $ 1,905,165

Significant Accounting Polici38

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include our accounts and those of our subsidiaries, which are wholly-owned or controlled by us. Entities which we do not control through our voting interest and entities which are variable interest entities, but where we are not the primary beneficiary, are accounted for under the equity method. See Note 5, "Debt and Preferred Equity Investments" and Note 6, "Investments in Unconsolidated Joint Ventures." All significant intercompany balances and transactions have been eliminated. We consolidate a variable interest entity, or VIE, in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. Included in commercial real estate properties on our consolidated balance sheets as of December 31, 2016 and 2015 are $ 1.7 billion and $200.7 million , respectively, related to our consolidated VIEs, excluding the Operating Partnership. Included in mortgages and other loans payable on our consolidated balance sheets as of December 31, 2016 and 2015 are $621.8 million and $101.1 million , respectively, related to our consolidated VIEs, excluding the Operating Partnership. As of December 31, 2015, assets held for sale and liabilities related to assets held for sale on the consolidated balance sheets did not include amounts related to consolidated VIEs.
Investment in Commercial Real Estate Properties	Investment in Commercial Real Estate Properties Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. A property to be disposed of is reported at the lower of its carrying value or its estimated fair value, less its cost to sell. Once an asset is held for sale, depreciation expense is no longer recorded. The Company adopted ASU 2014-08 effective January 1, 2015 which raised the threshold for disposals to qualify as discontinued operations to include only dispositions that represent a strategic shift in an entity’s operations. The guidance was applied prospectively for new disposals. As a result, the Company classified 388 Greenwich as held for sale as of March 31, 2016, 500 West Putnam as held for sale as of June 30, 2016, and 400 East 57th Street as held for sale as of September 30, 2016 and included the results of operations in continuing operations for all periods presented. The Company classified 242-252 Bedford Avenue in Brooklyn, New York as held for sale as of December 31, 2015, 570 & 574 Fifth Avenue and 140-150 Grand Street in White Plains, New York as held for sale as of September 30, 2015 and 131-137 Spring Street and 120 West 45th Street as of June 30, 2015 and included the results of operations in continuing operations for all periods presented. Discontinued operations included the results of operations of real estate assets sold or held for sale prior to January 1, 2015. This included 180 Maiden Lane, which was held for sale at December 31, 2014 and sold in January 2015, and 2 Herald Square, 985-987 Third Avenue and 673 First Avenue, which were sold during 2014. See Note 4, "Properties Held for Sale and Dispositions." Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows: Category Term Building (fee ownership) 40 years Building improvements shorter of remaining life of the building or useful life Building (leasehold interest) lesser of 40 years or remaining term of the lease Property under capital lease remaining lease term Furniture and fixtures four to seven years Tenant improvements shorter of remaining term of the lease or useful life Depreciation expense (including amortization of capital lease assets) totaled $ 783.5 million, $ 523.8 million , and $ 338.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Included in 2015 is $131.8 million of accelerated depreciation expense related to vacating the properties that comprise the One Vanderbilt development site. On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be other than temporarily impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted) to be generated by the property is less than the carrying value of the property. To the extent impairment has occurred, the loss will be measured as the excess of the carrying amount of the property over the calculated fair value of the property. We also evaluate our real estate properties for potential impairment when a real estate property has been classified as held for sale. Real estate assets held for sale are valued at the lower of either their carrying value or fair value less costs to sell. We do not believe that there were any indicators of impairment at any of our consolidated properties at December 31, 2016 . During the second quarter of 2016, we recorded a $10.4 million charge in connection with the sale of one property, 500 West Putnam, which closed in the third quarter of 2016. This charge is included in depreciable real estate reserves in the consolidated statements of operations. During the third quarter of 2015, we recorded a $19.2 million charge in connection with the sale of two of our properties, which closed in the fourth quarter of 2015. This charge is included in depreciable real estate reserves in the consolidated statements of operations. During the fourth quarter of 2015, we entered into an agreement to sell 885 Third Avenue and recorded a $6.6 million charge which was included in gain on sale of real estate, net in the consolidated statement of operations. At December 31, 2015, 885 Third Avenue was not reclassified as held for sale as a result of not meeting the criteria in ASC 360-10, Property, Plant and Equipment - Impairment and Disposal of Long-Lived Assets. We do not anticipate meeting the criteria for the full accrual method in ASC 360-20, Property, Plant and Equipment - Real Estate Sales until the third quarter of 2017, as a result the property will remain on our consolidated balance sheet until the criteria is met. We incur a variety of costs in the development and leasing of our properties. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year after major construction activity ceases. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction. Results of operations of properties acquired are included in the consolidated statements of operations from the date of acquisition. We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their fair values on the acquisition date. We expense transaction costs related to the acquisition of certain assets as incurred, which are included in transaction related costs on our consolidated statements of operations. In January, 2017, the FASB published ASU No. 2017-01, Business Combinations: Clarifying the Definition of a Business, which provides guidance as to whether transaction costs should be expensed or capitalized. Refer to Note 2, Accounting Standards Updates for the Company's adoption of the new guidance. When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of operations. In December 2015, we recognized a purchase price fair value adjustment of $40.1 million in connection with the consolidation of 600 Lexington Avenue. In May 2014, we recognized a purchase price fair value adjustment of $71.4 million in connection with the consolidation of 388-390 Greenwich Street. These acquisitions were previously accounted for as investments in unconsolidated joint ventures.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents.
Fair Value Measurements	Fair Value Measurements We are required to disclose fair value information with regard to our financial instruments, whether or not recognized in the consolidated balance sheets, for which it is practical to estimate fair value. The FASB guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. We measure and/or disclose the estimated fair value of financial assets and liabilities based on a hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity and the reporting entity’s own assumptions about market participant assumptions. This hierarchy consists of three broad levels: Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date; Level 2 - inputs other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly; and Level 3 - unobservable inputs for the asset or liability that are used when little or no market data is available. We follow this hierarchy for our assets and liabilities measured at fair value on a recurring and nonrecurring basis. In instances in which the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level of input that is significant to the fair value measurement in its entirety. Our assessment of the significance of the particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. We determine other than temporary impairment in real estate investments and debt and preferred equity investments, including intangibles utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, which are classified as Level 3 inputs. The marketable securities classified as Level 1 were derived from quoted prices in active markets. The valuation technique used to measure the fair value of the marketable securities classified as Level 2 were valued based on quoted market prices or model driven valuations using the significant inputs derived from or corroborated by observable market data. Marketable securities in an unrealized loss position are not considered to be other than temporarily impaired. We do not intend to sell these securities and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases. The fair value of derivative instruments is based on current market data received from financial sources that trade such instruments and are based on prevailing market data and derived from third party proprietary models based on well-recognized financial principles and reasonable estimates about relevant future market conditions, which are classified as Level 2 inputs. The financial assets and liabilities that are not measured at fair value on our consolidated balance sheets include cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued expenses, debt and preferred equity investments, mortgages and other loans payable and other secured and unsecured debt. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, and accounts payable and accrued expenses reported in our consolidated balance sheets approximates fair value due to the short term nature of these instruments. The fair value of debt and preferred equity investments, which is classified as Level 3, is estimated by discounting the future cash flows using current interest rates at which similar loans with the same maturities would be made to borrowers with similar credit ratings. The fair value of borrowings, which is classified as Level 3, is estimated by discounting the contractual cash flows of each debt to their present value using adjusted market interest rates, which is provided by a third-party specialist.
Investment in Marketable Securities	Investment in Marketable Securities We designate a security as held-to-maturity, available-for-sale, or trading at acquisition. As of December 31, 2016 , we did not have any securities designated as held-to-maturity or trading. We account for our available-for-sale securities at fair value pursuant to Accounting Standards Codification, or ASC, 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Any unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component. The cost of bonds and marketable securities sold is determined using the specific identification method.
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity in net income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us. The Company has performance guarantees under master leases at two joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures." We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at December 31, 2016 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some of the residual profit from such projects. When the risk and rewards of these arrangements are essentially the same as an investor or joint venture partner, we account for these arrangements as real estate investments under the equity method of accounting for investments. Otherwise, we account for these arrangements consistent with our loan accounting for our debt and preferred equity investments.
Restricted Cash	.
Deferred Lease Costs	Deferred Lease Costs Deferred lease costs consist of fees and direct costs incurred to initiate and renew operating leases and are amortized on a straight-line basis over the related lease term. Certain of our employees provide leasing services to the wholly-owned properties.
Deferred Financing Costs	Deferred Financing Costs Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close.
Revenue Recognition	Revenue Recognition Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year. We record a gain on sale of real estate when title is conveyed to the buyer, subject to the buyer's financial commitment being sufficient to provide economic substance to the sale and provided that we have no substantial economic involvement with the buyer. Interest income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt. Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as an adjustment to the interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cash flows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield. Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received. We may syndicate a portion of the loans that we originate or sell the loans individually. When a transaction meets the criteria for sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, original issue discounts, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of operations. Any fees received at the time of sale or syndication are recognized as part of investment income. Asset management fees are recognized on a straight-line basis over the term of the asset management agreement.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required.
Reserve for Possible Credit Losses	Reserve for Possible Credit Losses The expense for possible credit losses in connection with debt and preferred equity investments is the charge to earnings to increase the allowance for possible credit losses to the level that we estimate to be adequate, based on Level 3 data, considering delinquencies, loss experience and collateral quality. Other factors considered include geographic trends, product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish a provision for possible credit loss on each individual investment. When it is probable that we will be unable to collect all amounts contractually due, the investment is considered impaired. Where impairment is indicated on an investment that is held to maturity, a valuation allowance is measured based upon the excess of the recorded investment amount over the net fair value of the collateral. Any deficiency between the carrying amount of an asset and the calculated value of the collateral is charged to expense. We continue to assess or adjust our estimates based on circumstances of a loan and the underlying collateral. If additional information reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during years ended December 31, 2016 , 2015 , and 2014 . Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment.
Rent Expense	Rent Expense Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred lease payable on the consolidated balance sheets.
Underwriting Commissions and Costs	Underwriting Commissions and Costs Underwriting commissions and costs incurred in connection with our stock offerings are reflected as a reduction of additional paid-in-capital.
Exchangeable Debt Instruments	Exchangeable Debt Instruments The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, are bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate the liability component of exchangeable debt based on the present value of the contractual cash flows discounted at our comparable market conventional debt borrowing rate at the date of issuance. The difference between the principal amount and the fair value of the liability component is reported as a discount on the exchangeable debt that is accreted as additional interest expense from the issuance date through the contractual maturity date using the effective interest method. A portion of this additional interest expense may be capitalized to the development and redevelopment balances qualifying for interest capitalization each period. The liability component of the exchangeable debt is reported net of discounts on our consolidated balance sheets. We calculate the equity component of exchangeable debt based on the difference between the initial proceeds received from the issuance of the exchangeable debt and the fair value of the liability component at the issuance date. The equity component is included in additional paid-in-capital, net of issuance costs, on our consolidated balance sheets. We allocate issuance costs for exchangeable debt between the liability and the equity components based on their relative values.
Income Taxes	Income Taxes SL Green is taxed as a REIT under Section 856(c) of the Code. As a REIT, SL Green generally is not subject to Federal income tax. To maintain its qualification as a REIT, SL Green must distribute at least 90% of its REIT taxable income to its stockholders and meet certain other requirements. If SL Green fails to qualify as a REIT in any taxable year, SL Green will be subject to Federal income tax on SL Green's taxable income at regular corporate rates. SL Green may also be subject to certain state, local and franchise taxes. Under certain circumstances, Federal income and excise taxes may be due on SL Green's undistributed taxable income. The Operating Partnership is a partnership and, as a result, all income and losses of the partnership are allocated to the partners for inclusion in their respective income tax returns. The only provision for income taxes included in the consolidated statements of operations relates to the Operating Partnership’s consolidated taxable REIT subsidiaries. The Operating Partnership may also be subject to certain state, local and franchise taxes. Pursuant to amendments to the Code that became effective January 1, 2001, we have elected, and may elect in the future, to treat certain of our existing or newly created corporate subsidiaries as taxable REIT subsidiaries, or TRSs. In general, TRSs may perform non-customary services for the tenants of the Company, hold assets that we cannot hold directly and generally may engage in any real estate or non-real estate related business. The TRSs generate income, resulting in Federal and state income tax liability for these entities. During the years ended December 31, 2016 , 2015 and 2014 , we recorded Federal, state and local tax provisions of $2.8 million , $3.1 million , $7.8 million , respectively. We follow a two-step approach for evaluating uncertain tax positions. Recognition (step one) occurs when an enterprise concludes that a tax position, based solely on its technical merits, is more-likely-than-not to be sustained upon examination. Measurement (step two) determines the amount of benefit that is more-likely-than-not to be realized upon settlement. Derecognition of a tax position that was previously recognized would occur when a company subsequently determines that a tax position no longer meets the more-likely-than-not threshold of being sustained. The use of a valuation allowance as a substitute for derecognition of tax positions is prohibited.
Stock-Based Employee Compensation Plans	Stock-Based Employee Compensation Plans We have a stock-based employee compensation plan, described more fully in Note 14, "Share-based Compensation." The Company's stock options are recorded at fair value at the time of issuance. Fair value of the stock options is determined using the Black-Scholes option pricing model. The Black-Scholes model was developed for use in estimating the fair value of traded options, which have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of highly subjective assumptions including the expected stock price volatility. Because our plan has characteristics significantly different from those of traded options and because changes in the subjective input assumptions can materially affect the fair value estimate, in our opinion, the existing models do not necessarily provide a reliable single measure of the fair value of the employee stock options. Compensation cost for stock options, if any, is recognized over the vesting period of the award. Our policy is to grant options with an exercise price equal to the quoted closing market price of the Company's common stock on the grant date. Awards of stock or restricted stock are expensed as compensation over the benefit period based on the fair value of the stock on the grant date. For share-based awards with a performance or market measure, we recognize compensation cost over the requisite service period, using the accelerated attribution expense method. The requisite service period begins on the date the compensation committee of SL Green's board of directors authorizes the award, adopts any relevant performance measures and communicates the award to the employees. For programs with awards that vest based on the achievement of a performance condition or market condition, we determine whether it is probable that the performance condition will be met, and estimate compensation cost based on the fair value of the award at the applicable reporting date estimated using a binomial model or market quotes. For share-based awards for which there is no pre-established performance measure, we recognize compensation cost over the service vesting period, which represents the requisite service period, on a straight-line basis. In accordance with the provisions of our share-based incentive compensation plans, we accept the return of shares of the Company's common stock, at the current quoted market price, from certain key employees to satisfy minimum statutory tax-withholding requirements related to shares that vested during the period. Awards can also be made in the form of a separate series of units of limited partnership interest in the Operating Partnership called long-term incentive plan units, or LTIP units. LTIP units, which can be granted either as free-standing awards or in tandem with other awards under our stock incentive plan, are valued by reference to the value of the Company's common stock at the time of grant, and are subject to such conditions and restrictions as the compensation committee of the Company's board of directors may determine, including continued employment or service, computation of financial metrics and/or achievement of pre-established performance goals and objectives.
Derivative Instruments	Derivative Instruments In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collars and floors, to manage, or hedge, interest rate risk. Effectiveness is essential for those derivatives that we intend to qualify for hedge accounting. Some derivative instruments are associated with an anticipated transaction. In those cases, hedge effectiveness criteria also require that it be probable that the underlying transaction occurs. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract. To determine the fair values of derivative instruments, we use a variety of methods and assumptions that are based on market conditions and risks existing at each balance sheet date. For the majority of financial instruments including most derivatives, long-term investments and long-term debt, standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost, and termination cost are used to determine fair value. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized. In the normal course of business, we are exposed to the effect of interest rate changes and limit these risks by following established risk management policies and procedures including the use of derivatives. To address exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices and manage the cost of borrowing obligations. We use a variety of commonly used derivative products that are considered plain vanilla derivatives. These derivatives typically include interest rate swaps, caps, collars and floors. We expressly prohibit the use of unconventional derivative instruments and using derivative instruments for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. We may employ swaps, forwards or purchased options to hedge qualifying forecasted transactions. Gains and losses related to these transactions are deferred and recognized in net income as interest expense in the same period or periods that the underlying transaction occurs, expires or is otherwise terminated. Hedges that are reported at fair value and presented on the balance sheet could be characterized as cash flow hedges or fair value hedges. Interest rate caps and collars are examples of cash flow hedges. Cash flow hedges address the risk associated with future cash flows of interest payments. For all hedges held by us and which were deemed to be fully effective in meeting the hedging objectives established by our corporate policy governing interest rate risk management, no net gains or losses were reported in earnings. The changes in fair value of hedge instruments are reflected in accumulated other comprehensive income. For derivative instruments not designated as hedging instruments, the gain or loss, resulting from the change in the estimated fair value of the derivative instruments, is recognized in current earnings during the period of change.
Earnings per Share of the Company	Earnings per Share of the Company The Company presents both basic and diluted earnings per share, or EPS. Basic EPS excludes dilution and is computed by dividing net income or loss attributable to common stockholders by the weighted average number of common shares outstanding during the period. Basic EPS includes participating securities, consisting of unvested restricted stock that receive nonforfeitable dividends similar to shares of common stock. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock, where such exercise or conversion would result in a lower EPS amount. Diluted EPS also includes units of limited partnership interest. The dilutive effect of stock options is reflected in the weighted average diluted outstanding shares calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Earnings per Unit of the Operating Partnership	Earnings per Unit of the Operating Partnership The Operating Partnership presents both basic and diluted earnings per unit, or EPU. Basic EPU excludes dilution and is computed by dividing net income or loss attributable to common unitholders by the weighted average number of common units outstanding during the period. Basic EPU includes participating securities, consisting of unvested restricted units that receive nonforfeitable dividends similar to shares of common units. Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common units were exercised or converted into common units, where such exercise or conversion would result in a lower EPU amount. The dilutive effect of unit options is reflected in the weighted average diluted outstanding units calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash investments, debt and preferred equity investments and accounts receivable. We place our cash investments in excess of insured amounts with high quality financial institutions. The collateral securing our debt and preferred equity investments is located in New York City. See Note 5, "Debt and Preferred Equity Investments." We perform ongoing credit evaluations of our tenants and require most tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant's lease obligation, they are a measure of good faith and a source of funds to offset the economic costs associated with lost revenue and the costs associated with re-tenanting a space. The properties in our real estate portfolio are primarily located in Manhattan, we also have properties located in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey. The tenants located in our buildings operate in various industries.
Reclassification	Reclassification Certain prior year balances have been reclassified to conform to our current year presentation
Accounting Standards Updates

Organization and Basis of Pre39

Organization and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of December 31, 2016 , we owned the following interests in properties in the New York Metropolitan area, primarily in midtown Manhattan. Our investments in the New York Metropolitan area also include investments in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties: Consolidated Unconsolidated Total Location Property Type Number of Properties Approximate Square Feet (unaudited) Number of Properties Approximate Square Feet (unaudited) Number of Properties Approximate Square Feet (unaudited) Weighted Average Occupancy (1) (unaudited) Commercial: Manhattan Office 24 16,054,606 7 6,558,139 31 22,612,745 94.9 % Retail 10 (2) 418,093 9 347,970 19 766,063 85.6 % Development/Redevelopment 3 42,635 3 770,514 6 813,149 52.3 % Fee Interest 1 176,530 1 26,926 2 203,456 100.0 % 38 16,691,864 20 7,703,549 58 24,395,413 93.2 % Suburban Office 25 4,113,800 2 640,000 27 4,753,800 82.6 % Retail 1 52,000 — — 1 52,000 100.0 % Development/Redevelopment 1 1,000 1 — 2 1,000 100.0 % 27 4,166,800 3 640,000 30 4,806,800 82.8 % Total commercial properties 65 20,858,664 23 8,343,549 88 29,202,213 91.5 % Residential: Manhattan Residential 3 (2) 472,105 18 3,247,764 21 3,719,869 83.8 % Suburban Residential — — — — — — — % Total residential properties 3 472,105 18 3,247,764 21 3,719,869 83.8 % Total portfolio 68 21,330,769 41 11,591,313 109 32,922,082 90.6 % ____________________________________________________________________ (1) The weighted average occupancy for commercial properties represents the total occupied square feet divided by total square footage at acquisition. The weighted average occupancy for residential properties represents the total occupied units divided by total available units. (2) As of December 31, 2016 , we owned a building that was comprised of approximately 270,132 square feet (unaudited) of retail space and approximately 222,855 square feet (unaudited) of residential space. For the purpose of this report, we have included the building in the number of retail properties we own. However, we have included only the retail square footage in the retail approximate square footage, and have listed the balance of the square footage as residential square footage.

Significant Accounting Polici40

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of estimated useful lives	Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows: Category Term Building (fee ownership) 40 years Building improvements shorter of remaining life of the building or useful life Building (leasehold interest) lesser of 40 years or remaining term of the lease Property under capital lease remaining lease term Furniture and fixtures four to seven years Tenant improvements shorter of remaining term of the lease or useful life
Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)	The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Identified intangible assets (included in other assets): Gross amount $ 651,099 $ 939,518 Accumulated amortization (410,930 ) (403,747 ) Net (1) $ 240,169 $ 535,771 Identified intangible liabilities (included in deferred revenue): Gross amount $ 655,930 $ 866,561 Accumulated amortization (464,749 ) (486,928 ) Net (1) $ 191,181 $ 379,633 ____________________________________________________________________ (1) As of December 31, 2016 , no net intangible assets and no net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale.
Schedule of estimated annual amortization of acquired above-market leases, net of acquired below-market leases	The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands): 2017 $ (19,286 ) 2018 (17,022 ) 2019 (16,300 ) 2020 (15,279 ) 2021 (6,356 )
Schedule of estimated annual amortization of all other identifiable assets	The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands): 2017 $ 24,801 2018 17,600 2019 14,780 2020 12,742 2021 8,986
Schedule of marketable securities	At December 31, 2016 and 2015 , we held the following marketable securities (in thousands): December 31, 2016 2015 Equity marketable securities $ 48,315 $ 4,704 Mortgage-backed securities 36,795 40,434 Total marketable securities available-for-sale $ 85,110 $ 45,138
Schedule of Restated Balance Sheets	.
Schedule of Error Corrections and Prior Period Adjustments	.

Property Acquisitions (Tables)

Property Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Acquisitions
Schedule of Fair Value of Equity Interest Immediately Before Acquisition Date	The acquisition-date fair value of the equity interest in 600 Lexington Avenue and 388-390 Greenwich Street, which were acquired in 2015 and 2014, respectively, immediately before the acquisition date as well as the purchase price fair value, as determined in accordance with the methodology set out in the prior sentence, are as follows (in thousands): 600 Lexington Avenue 388-390 Greenwich Street Contract purchase price $ 284,000 $ 1,585,000 Net consideration funded by us at closing, excluding consideration financed by debt (79,085 ) (208,614 ) Debt assumed (112,795 ) (1,162,379 ) Fair value of retained equity interest 92,120 214,007 Equity and/or debt investment held (54,575 ) (148,025 ) Other (1) 2,533 5,464 Purchase price fair value adjustment $ 40,078 $ 71,446 ___________________________________________________________________ (1) Includes the acceleration of a deferred leasing commission from the joint venture to the Company.
Summary of Unaudited Pro Forma Basis Results of Operations	The following table summarizes, on an unaudited pro forma basis, the results of operations of 11 Madison Avenue, which are included in the consolidated results of operations for years ended December 31, 2015 and 2014 as though the acquisition of 11 Madison Avenue was completed on January 1, 2014. The supplemental pro forma data is not necessarily indicative of what the actual results of operations would have been assuming the transactions had been completed as set forth above, nor do they purport to represent our results of operations for future periods. Year Ended December 31, (in thousands, except per share/unit amounts) 2015 2014 Actual revenues since acquisition $ 29,865 Actual net income since acquisition 159 Pro forma revenues 1,657,937 1,540,525 Pro forma income from continuing operations (1) 102,440 376,710 Pro forma basic earnings per share $ 0.76 $ 7.00 Pro forma diluted earnings per share $ 0.75 $ 6.92 Pro forma basic earnings per unit $ 0.76 $ 7.00 Pro forma diluted earnings per unit $ 0.75 $ 6.92 ______________________________________________________________________ (1) The pro forma income from continuing operations for the years ended December 31, 2015 and 2014 includes the effect of the incremental borrowings, including a $ 1.4 billion , 10 -year, interest only, fixed rate mortgage financing carrying a per annum stated interest rate of 3.838% to complete the acquisition and the preliminary allocation of purchase price. In addition, the pro forma income from continuing operations for the year ended December 31, 2014 was adjusted to include the sale of real estate assets for properties that have closed either subsequent to December 31, 2015 or we are currently under contract to sell in connection with 11 Madison Avenue, as if the sales were completed on January 1, 2014. The pro forma income from continuing operations for the year ended December 31, 2015 excl
2016 Acquisitions [Member]
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	During the year ended December 31, 2016 , the property listed below was acquired from a third party. The following summarizes our final allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of this acquisition (in thousands): 183 Broadway Acquisition Date March 2016 Ownership Type Fee Interest Property Type Retail/Residential Purchase Price Allocation: Land $ 5,799 Building and building leasehold 23,431 Above-market lease value — Acquired in-place leases 773 Other assets, net of other liabilities 20 Assets acquired 30,023 Mark-to-market assumed debt — Below-market lease value (1,523 ) Derivatives — Liabilities assumed (1,523 ) Purchase price $ 28,500 Net consideration funded by us at closing, excluding consideration financed by debt $ 28,500 Equity and/or debt investment held $ — Debt assumed $ —
2015 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed		During the year ended December 31, 2016 , we finalized the purchase price allocations for the following 2015 acquisitions based on facts and circumstances that existed at the acquisition date for each property (in thousands): 600 Lexington Avenue (1)(2) 187 Broadway and 5 & 7 Dey Street (1)(3) 11 Madison Avenue (1) 110 Greene Street (1)(4) Upper East Side Residential (1)(5) 1640 Flatbush Avenue (1) Acquisition Date December 2015 August 2015 August 2015 July 2015 June 2015 March 2015 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Office Residential/Retail Office Office Residential/Retail Retail Purchase Price Allocation: Land $ 81,670 $ 20,266 $ 675,776 $ 45,120 $ 48,152 $ 6,226 Building and building leasehold 182,447 42,468 1,553,602 215,470 — 501 Above-market lease value 3,320 17 19,764 — — — Acquired in-place leases 22,449 3,621 366,949 8,967 1,922 146 Other assets, net of other liabilities — — — — — — Assets acquired 289,886 66,372 2,616,091 269,557 50,074 6,873 Mark-to-market assumed debt (55 ) — — — — — Below-market lease value (5,831 ) (3,226 ) (187,732 ) (14,557 ) — (73 ) Derivatives — — — — — — Liabilities assumed (5,886 ) (3,226 ) (187,732 ) (14,557 ) — (73 ) Purchase price $ 284,000 $ 63,146 $ 2,428,359 $ 255,000 $ 50,074 $ 6,800 Net consideration funded by us at closing, excluding consideration financed by debt $ 79,085 $ — $ — $ — $ — $ — Equity and/or debt investment held $ 54,575 $ — $ — $ — $ — $ — Debt assumed $ 112,795 $ — $ — $ — $ — $ — ____________________________________________________________________ (1) Based on our preliminary analysis of the purchase price, we had allocated $97.0 million and $180.2 million to land and building, respectively, at 600 Lexington Avenue, $22.1 million and $41.0 million to land and building, respectively, at 187 Broadway and 5&7 Dey Street, $849.9 million and $1.6 billion to land and building, respectively, at 11 Madison Avenue, $89.3 million and $165.8 million to land and building, respectively, at 110 Greene Street, and $17.5 million and $32.5 million to land and building, respectively, at the Upper Eastside Residential Property and $6.1 million and $0.7 million to land and building, respectively, at 1640 Flatbush Avenue. The impact to our consolidated statements of operations for the twelve months ended December 31, 2015 was an increase in rental revenue of $7.8 million for the amortization of aggregate below-market leases and an additional $18.5 million of depreciation expense. (2) In December 2015, we acquired Canada Pension Plan Investment Board's 45% interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $277.3 million . We recognized a purchase price fair value adjustment of $40.1 million upon closing of this transaction. This property, which we initially acquired in May 2010, was previously accounted for as an investment in unconsolidated joint ventures. (3) We acquired this property for consideration that included the issuance of $10.0 million and $26.9 million aggregate liquidation preferences of Series R and S Preferred Units, respectively, of limited partnership interest of the Operating Partnership and cash. (4) We acquired a 90.0% controlling interest in this property for consideration that included the issuance of $5.0 million and $6.7 million aggregate liquidation preferences of Series P and Q Preferred Units, respectively, of limited partnership interest of the Operating Partnership and cash. (5) We, along with our joint venture partner, acquired this property for consideration that included the issuance of $13.8 million aggregate liquidation preference of Series N Preferred Units of limited partnership interest of the Operating Partnership and cash. We hold a 95.1% controlling interest in this joint venture.
2014 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	During the year ended December 31, 2014, the properties listed below were acquired from third parties. The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands): 102 Greene Street (1) 635 Madison Avenue (1) 719 Seventh Avenue (1)(2) 115 Spring Street (1) 388-390 Greenwich Street (1)(3) Acquisition Date October 2014 September 2014 July 2014 July 2014 May 2014 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Retail Land Development Retail Office Purchase Price Allocation: Land $ 8,215 $ 205,632 $ 41,850 $ 11,078 $ 516,292 Building and building leasehold 26,717 15,805 — 44,799 964,434 Above-market lease value — — — — — Acquired in-place leases 1,015 17,345 — 2,037 302,430 Other assets, net of other liabilities 3 — — — 6,495 Assets acquired 35,950 238,782 41,850 57,914 1,789,651 Mark-to-market assumed debt — — — — — Below-market lease value 3,701 85,036 — 4,789 186,782 Derivatives — — — — 18,001 Liabilities assumed 3,701 85,036 — 4,789 204,783 Purchase price $ 32,249 $ 153,746 $ 41,850 $ 53,125 $ 1,584,868 Net consideration funded by us at closing, excluding consideration financed by debt $ 32,249 $ 153,746 $ 41,850 $ 53,125 $ 208,614 Equity and/or debt investment held $ — $ — $ — $ — $ 148,025 Debt assumed $ — $ — $ — $ — $ 1,162,379 ____________________________________________________________________ (1) Based on our preliminary analysis of the purchase price, we had allocated $11.3 million and $21.0 million to land and building, respectively, at 102 Greene Street, $153.7 million to land at 635 Madison Avenue, $14.4 million and $26.7 million to land and building, respectively, at 719 Seventh Avenue, $15.9 million and $37.2 million to land and building, respectively, at 115 Spring Street and $558.7 million and $1.0 billion to land and building, respectively, at 388-390 Greenwich. The impact to our consolidated statements of operations for the twelve months ended December 31, 2015 was $7.6 million in rental revenue for the amortization of aggregate below-market leases and $10.3 million of depreciation expense. (2) We, along with our joint venture partner, acquired this property for consideration that included the issuance of $14.1 million aggregate liquidation preference of Series L Preferred Units of limited partnership interest of the Operating Partnership and $9.5 million aggregate liquidation preference of Series K Preferred Units of limited partnership interest of the Operating Partnership. We hold a 75.0% controlling interest in this joint venture. (3) In May 2014, we acquired Ivanhoe Cambridge, Inc.'s 49.65% economic interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $1.585 billion . Simultaneous with the closing, we refinanced the previous mortgage with a $1.45 billion mortgage. We also assumed the existing derivative instruments, which swapped $504.0 million of the mortgage to fixed rate (in October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on an additional $500.0 million portion of this mortgage. See Note 8, "Mortgages and Other Loans Payable" for further details). We recognized a purchase price fair value adjustment of $71.4 million upon closing of this transaction. This property, which we initially acquired in December 2007, was previously accounted for as an investment in unconsolidated joint ventures.

Properties Held for Sale and 42

Properties Held for Sale and Property Dispositions (Tables)	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Summary of properties sold and income from discontinued operations	The following table summarizes net income from discontinued operations for the years ended December 31, 2016 , 2015 , and 2014 respectively (in thousands): Year Ended December 31, 2016 2015 2014 Revenues Rental revenue $ — $ 236 $ 51,090 Escalation and reimbursement revenues — (127 ) 4,646 Other income — — 23 Total revenues — 109 55,759 Operating expenses — (631 ) 7,772 Real estate taxes — 250 7,156 Ground rent — — 3,001 Transaction related costs — (49 ) 89 Interest expense, net of interest income — 109 12,652 Amortization of deferred financing costs — 3 433 Depreciation and amortization — — 5,581 Total expenses — (318 ) 36,684 Net income from discontinued operations $ — $ 427 $ 19,075 The following table summarizes the properties sold during the years ended December 31, 2016 , 2015 , and 2014 : Property Disposition Date Property Type (unaudited)Approximate Usable Square Feet Sales Price (1) (in millions) Gain (Loss) on Sale (2) (in millions) 400 East 57th Street October 2016 Residential 290,482 $ 83.3 $ 23.9 11 Madison Avenue (3) August 2016 Office 2,314,000 2,605.0 3.6 500 West Putnam July 2016 Office 121,500 41.0 (10.4 ) 388 Greenwich June 2016 Office 2,635,000 2,002.3 206.5 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) 248-252 Bedford Avenue February 2016 Residential 66,611 55.0 15.3 885 Third Avenue (4) February 2016 Land 607,000 453.0 — 140-150 Grand Street (5) December 2015 Office/Development 215,100 32.0 (20.1 ) 570 & 574 Fifth Avenue December 2015 Development 24,327 125.4 24.6 120 West 45th Street September 2015 Office 440,000 365.0 58.6 131-137 Spring Street (6) August 2015 Office 68,342 277.8 101.1 180 Maiden Lane January 2015 Office 1,090,000 470.0 17.0 2 Herald Square November 2014 Land 354,400 365.0 18.8 985-987 Third Avenue July 2014 Development 13,678 68.7 29.8 673 First Avenue May 2014 Office 422,000 145.0 117.6 ____________________________________________________________________ (1) Sales price represents the actual sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 400 East 57th Street, 11 Madison Avenue, 388 Greenwich, 248-252 Bedford Avenue, 570 & 574 Fifth Avenue, 120 West 45th Street, 131-137 Spring Street, 180 Maiden Lane, 2 Herald Square, 985-987 Third Avenue, and 673 First Avenue are net of $1.0 million , $0.6 million , $1.6 million , $1.3 million , $4.0 million , $2.0 million , $4.1 million , $0.8 million , $2.5 million , $1.3 million , and $3.4 million in employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In August 2016, we sold a 40% interest in 11 Madison Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property was accounted for under the profit sharing method. In November 2016, the Company obtained consent to the modifications to the mortgage on the property, which resulted in the Company achieving sale accounting on the transaction. See Note 6, "Investments in Unconsolidated Joint Ventures." (4) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and, therefore, remains consolidated. We expect to deconsolidate the property in or before July 2017. An estimated loss relating to the sale of $6.6 million was recorded in December 2015. (5) Gain/(loss) on sale includes a $19.2 million charge that was recorded during the third quarter of 2015. This charge is included in depreciable real estate reserves in the consolidated statement of operations. (6) We sold an 80% interest in 131-137 Spring Street and have subsequently accounted for our interest in the properties as an investment in unconsolidated joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures."

Debt and Preferred Equity Inv43

Debt and Preferred Equity Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Summary of debt investments	As of December 31, 2016 and 2015 , we held the following debt investments with an aggregate weighted average current yield of 9.34% at December 31, 2016 (in thousands): Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Jr. Mortgage Participation/Mezzanine Loan $ — $ 1,109,000 $ 193,422 $ 104,661 March 2017 Mezzanine Loan (3a) — 502,100 66,129 41,115 June 2017 Mortgage Loan (4) — — 26,311 26,262 February 2019 Mortgage Loan — — 380 513 August 2019 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan (3b) — 88,466 12,692 19,936 November 2023 Mezzanine Loan (3c) — 115,000 12,925 24,916 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 15,000 — November 2026 Mezzanine Loan (5) — — — 72,102 Mezzanine Loan (6) — — — 49,691 Jr. Mortgage Participation (7) — — — 49,000 Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Other (7)(8) — — — 23,510 Other (7)(8) — — — 66,183 Total fixed rate $ — $ 2,264,566 $ 360,359 $ 511,389 Floating Rate Investments: Mortgage/Mezzanine Loan (3d)(9) 36,042 — 145,239 134,264 January 2017 Mezzanine Loan (10) — 118,949 29,998 28,551 January 2017 Mezzanine Loan (3e)(11) — 40,000 15,369 68,977 June 2017 Mortgage/Mezzanine Loan — — 32,847 — June 2017 Mortgage/Mezzanine Loan — — 22,959 22,877 July 2017 Mortgage/Mezzanine Loan — — 16,960 16,901 September 2017 Mortgage/Mezzanine Loan 3,479 — 20,423 19,282 October 2017 Mezzanine Loan — 60,000 14,957 14,904 November 2017 Mezzanine Loan (3f) — 85,000 15,141 29,505 December 2017 Mezzanine Loan (3g) — 65,000 14,656 28,563 December 2017 Mortgage/Mezzanine Loan (3h) 795 — 15,051 14,942 December 2017 Jr. Mortgage Participation — 40,000 19,913 19,846 April 2018 Mezzanine Loan — 175,000 34,844 34,725 April 2018 Mortgage/Mezzanine Loan (12) 523 20,523 10,863 31,210 August 2018 Mortgage Loan — — 19,840 — August 2018 Mezzanine Loan — 65,000 14,880 — August 2018 Mezzanine Loan — 37,500 14,648 — September 2018 Mezzanine Loan 2,324 45,025 34,502 — October 2018 Mezzanine Loan — 335,000 74,476 — November 2018 Mezzanine Loan — 33,000 26,850 26,777 December 2018 Mezzanine Loan 3,317 165,326 56,114 52,774 December 2018 Mezzanine Loan 15,794 259,229 63,137 49,625 December 2018 Mezzanine Loan 14,715 199,935 64,505 — December 2018 Mezzanine Loan — 45,000 12,104 — January 2019 Mezzanine Loan 6,383 16,383 5,410 — January 2019 Mezzanine Loan — 38,000 21,891 21,845 March 2019 Mezzanine Loan — 265,000 24,707 — April 2019 Mortgage/Jr. Mortgage Participation Loan 33,573 183,300 65,554 — August 2019 Mezzanine Loan 2,500 187,500 37,322 — September 2019 Mortgage/Mezzanine Loan 82,888 — 111,819 — September 2019 Mortgage/Mezzanine Loan 35,630 — 33,682 — January 2020 Mezzanine Loan (13) 32,502 445,483 125,911 — January 2020 Jr. Mortgage Participation/Mezzanine Loan — 30,000 15,606 — July 2021 Mezzanine Loan (14) — — — 49,751 Mezzanine Loan (14) — — — 13,731 Mezzanine Loan (15) — — — 99,530 Mortgage/Mezzanine Loan (16) — — — 94,901 Jr. Mortgage Participation/Mezzanine Loan (5) — — — 20,510 Loan Type December 31, 2016 Future Funding Obligations December 31, 2016 Senior Financing December 31, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Mezzanine Loan (17) — — — 22,625 Mezzanine Loan (18) — — — 74,700 Mezzanine Loan (19) — — — 66,398 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 18,395 Mezzanine Loan (20) — — — 40,346 Total floating rate $ 270,465 $ 2,955,153 $ 1,232,178 $ 1,116,455 Total $ 270,465 $ 5,219,719 $ 1,592,537 $ 1,627,844 ____________________________________________________________________ (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised options. (3) Carrying value is net of the following amount that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting: (a) $41.3 million , (b) $5.0 million , (c) $12.0 million , (d) $36.3 million , (e) $14.5 million , (f) $14.6 million , (g) $14.1 million , and (h) $5.1 million . (4) In September 2014, we acquired a $26.4 million mortgage loan at a $0.2 million discount and a $5.7 million junior mortgage participation at a $5.7 million discount. The junior mortgage participation was a nonperforming loan at acquisition and is currently on non-accrual status. (5) This loan was repaid in July 2016. (6) In April 2016 we executed a purchase option to acquire a 20% interest in the underlying asset at a previously agreed upon purchase option valuation, and our mezzanine loan was simultaneously repaid. (7) This loan was repaid in March 2016. (8) This loan was collateralized by defeasance securities. (9) This loan was refinanced at maturity in January 2017 by us at market rates, and therefore it was not considered a troubled-debt restructuring. (10) This loan was extended in January 2017. (11) In March 2016, the mortgage was sold. (12) In January 2016, the loans were modified. In March 2016, the mortgage was sold. (13) $66.1 million of outstanding principal was syndicated in February 2017. (14) This loan was repaid in December 2016. (15) This loan was repaid in November 2016. (16) This loan was repaid in September 2016. (17) This loan was repaid in June 2016. (18) This loan was repaid in May 2016. (19) In March 2016, we contributed our interest in the loan in exchange for a joint venture interest which is now accounted for under the equity method of accounting. It is included in unconsolidated joint ventures on the consolidated balance sheets. (20) This loan was repaid in February 2016.
Summary of preferred equity investments	As of December 31, 2016 and 2015 , we held the following preferred equity investments with an aggregate weighted average current yield of 8.16% at December 31, 2016 (in thousands): Type December 31, 2016 Future Funding Obligations December 31, 2016 December 31, 2016 (1) December 31, 2015 (1) Mandatory Redemption (2) Preferred Equity $ — $ 71,486 $ 9,982 $ 9,967 March 2018 Preferred Equity — 58,786 37,893 32,209 November 2018 $ — $ 130,272 $ 47,875 $ 42,176 ____________________________________________________________________ (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options.
Rollforward of total allowance for loan loss reserves	The following table is a rollforward of our total loan loss reserves at December 31, 2016 , 2015 and 2014 (in thousands): December 31, 2016 2015 2014 Balance at beginning of year $ — $ — $ 1,000 Expensed — — — Recoveries — — — Charge-offs and reclassifications — — (1,000 ) Balance at end of period $ — $ — $ —

Investments in Unconsolidated44

Investments in Unconsolidated Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Schedule of general information on joint ventures	The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2016 , 2015 , and 2014 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain (Loss) on Sale (in thousands) (2) EOP Denver 0.48% September 2016 Ownership Interest $ 180,700 $ 300 33 Beekman (3) 45.90% May 2016 Property 196,000 33,000 EOP Denver 4.79% March 2016 Ownership Interest 180,700 2,800 7 Renaissance Square 50.00% March 2016 Property 20,700 4,200 1 Jericho Plaza (4) 66.11% February 2016 Ownership Interest 95,200 3,300 The Meadows 50.00% August 2015 Property 121,100 (1,600 ) 315 West 36th Street 35.50% September 2015 Ownership Interest 115,000 16,300 180 Broadway (5) 25.50% September 2014 Property 222,500 16,500 747 Madison Avenue (6) 33.33% May 2014 Ownership Interest 160,000 — West Coast Office portfolio 42.02% March 2014 Ownership Interest 756,000 85,600 21-25 West 34th Street (7) 49.90% January 2014 Ownership Interest 114,900 20,900 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain or loss. The gain on sale is net of $2.3 million employee compensation awards accrued in connection with the realization of these investment gains as bonuses to certain employees that were instrumental in realizing the gains on sale. (3) In connection with the sale of the property, we also recognized a promote of $10.8 million . (4) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (5) In connection with the sale of the property, we also recognized a promote of $3.3 million . (6) We sold our ownership interest in the joint venture, which owns 100% interest as tenant-in-common in 30 East 65th Street Corporation and the related proprietary lease of five cooperative apartment units in the property. We also recognized a promote of $10.3 million and originated a $30.0 million preferred equity investment. Given our continuing involvement as a preferred equity holder, we deferred the gain on sale of $13.1 million as we did not meet the requirements of a sale under the full accrual method. We, along with our joint venture partners, retained one apartment unit at this property. (7) We sold our ownership interest in the joint venture. We, along with our joint venture partner, retained approximately 91,300 square feet (unaudited) of development rights at the property. As of December 31, 2016 and 2015 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type December 31, 2016 December 31, 2015 Initial Maturity Date Mezzanine Loan and Preferred Equity $ 100,000 $ 99,936 March 2017 Mezzanine Loan (1) 45,622 45,942 February 2022 Mezzanine Loan (2) 24,542 — July 2036 $ 170,164 $ 145,878 (1) We have an option to convert our loan to an equity interest subject to certain conditions. We have determined that our option to convert the loan to equity is not a derivative financial instrument pursuant to GAAP. (2) The Company has the ability to convert this loan into an equity position starting in 2021 and the borrower is able to force this conversion in 2024. The table below provides general information on each of our joint ventures as of December 31, 2016 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 January 2000 $ 95,800 717 Fifth Avenue Jeff Sutton/Private Investor 10.92% 10.92% 119,500 September 2006 251,900 800 Third Avenue Private Investors 60.52% 60.52% 526,000 December 2006 285,000 1745 Broadway Ivanhoe Cambridge, Inc. 56.88% 56.88% 674,000 April 2007 520,000 Jericho Plaza (3) Onyx Equities/Credit Suisse 11.67% 11.67% 640,000 April 2007 210,000 11 West 34th Street Private Investor/ Jeff Sutton 30.00% 30.00% 17,150 December 2010 10,800 3 Columbus Circle (4) The Moinian Group 48.90% 48.90% 741,500 January 2011 500,000 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 March 2011 400,000 1552-1560 Broadway (5) Jeff Sutton 50.00% 50.00% 35,897 August 2011 136,550 724 Fifth Avenue Jeff Sutton 50.00% 50.00% 65,040 January 2012 223,000 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 February 2012 252,500 521 Fifth Avenue Plaza Global Real Estate Partners LP 50.50% 50.50% 460,000 November 2012 315,000 21 East 66th Street (6) Private Investors 32.28% 32.28% 16,736 December 2012 75,000 650 Fifth Avenue (7) Jeff Sutton 50.00% 50.00% 69,214 November 2013 — 121 Greene Street Jeff Sutton 50.00% 50.00% 7,131 September 2014 27,400 Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 175-225 Third Street Brooklyn, New York KCLW 3rd Street LLC/LIVWRK LLC 95.00% 95.00% — October 2014 74,600 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 November 2014 295,000 Stonehenge Portfolio Various Various Various 2,046,733 February 2015 36,668 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 76 11th Avenue (8) Oxford/Vornado 33.33% 35.09% 764,000 March 2016 138,240 605 West 42nd Street (9) The Moinian Group 20.00% 20.00% 927,358 April 2016 759,000 11 Madison Avenue (10) PGIM Real Estate 60.00% 60.00% 2,314,000 August 2016 2,605,000 333 East 22nd Street (11) Private Investors 33.33% 33.33% 26,926 August 2016 — 400 E 57th Street (12) Blackrock, Inc and Stonehenge Partners 51.00% 41.00% 290,482 October 2016 170,000 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of December 31, 2016 . Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) Acquisition date and price represent the date on which the Company initially acquired an interest in the joint venture and the actual or implied gross purchase price for the joint venture on that date. Acquisition date and price are not adjusted for subsequent acquisitions or dispositions of interest. (3) In connection with the restructuring of the joint venture and the loan on the property, our 20.26% ownership increased by 57.52% in October 2015. Our ownership percentage was reduced 66.11% in the first quarter of 2016 upon completion of the restructuring of the venture. (4) As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns floors three through eight at the property. Because the joint venture has an option to repurchase these floors, the gain associated with this sale was deferred. (5) The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet. The joint venture also owns a long-term leasehold interest in the retail space and certain other spaces at 1560 Broadway, which is adjacent to 1552 Broadway. (6) We hold a 32.28% interest in three retail and two residential units at the property and a 16.14% interest in three residential units at the property. (7) The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. In connection with the ground lease obligation, SLG provided a performance guaranty and our joint venture partner executed a contribution agreement to reflect its pro rata obligation. In the event the property is converted into a condominium unit and the landlord elects the purchase option, the joint venture shall be obligated to acquire the unit at the then fair value. In November 2016, the joint venture entered into a lease for an additional 36,890 square feet at the property for a term lasting sixteen years and ten months. (8) The joint venture owns two mezzanine notes secured by interests in the entity that owns 76 11th Avenue. The difference between our ownership interest and our economic interest results from our right to 50% of the total exit fee while each of our partners is entitled to receive 25% of the total exit fee and our right to 38% of the total extension fee while each of our partners is entitled to receive 31% of the total extension fee. (9) The Company was granted an option to purchase the interest at an agreed upon valuation in July 2014 when it originated a $50.0 million mezzanine loan to the project's developer. The mezzanine loan was repaid prior to the closing of the Company's acquisition of its joint venture interest. (10) In August 2016, we closed on the sale of a 40% interest in 11 Madison. The sale did not meet the criteria for sale accounting and as a result the property was accounted for under the profit sharing method. Under the profit sharing method the Company recognized its share of the operations of the property and also recognized the other partner's share of depreciation. In November 2016, the Company obtained consent to the modifications to the mortgage on the property, which resulted in the Company achieving sale accounting on the transaction. The achievement of sale accounting discontinued recognition of the other partner's share of depreciation from that date and had no effect on the balance sheet presentation of the investment. Included in equity in net income from unconsolidated joint ventures is $8.4 million of depreciation for the year ended December 31, 2016 representing the other partner's share of depreciation. (11) The joint venture acquired a leasehold interest in the property in October 2016. (12) In October 2016, the Company sold a 49% interest in this property to Blackrock, Inc. The Company's interest in the property was sold within a consolidated joint venture owned 90% by the Company and 10% by Stonehenge. The transaction resulted in the deconsolidation of the venture's remaining 51% interest in the property. The Company's joint venture with Stonehenge remains consolidated resulting in the combined 51% interest being shown within investments in unconsolidated joint ventures on the Company's balance sheet.
Schedule of first mortgage notes payable collateralized by the respective joint venture properties and assignment of leases	The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2016 and 2015 , respectively, are as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 31, 2016 December 31, 2015 Fixed Rate Debt: 1745 Broadway (2) January 2017 5.68 % $ 340,000 $ 340,000 521 Fifth Avenue November 2019 3.73 % 170,000 170,000 717 Fifth Avenue (3) July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (3) July 2022 6.52 % 355,328 325,704 21 East 66th Street April 2023 3.60 % 12,000 12,000 3 Columbus Circle March 2025 3.61 % 350,000 350,000 11 Madison Avenue September 2025 3.84 % 1,400,000 — 800 Third Avenue February 2026 3.24 % 177,000 20,910 400 East 57th Street November 2026 3.00 % 100,000 — Stonehenge Portfolio (4) Various 4.19 % 362,518 430,627 280 Park Avenue — 692,963 7 Renaissance — 2,927 Total fixed rate debt $ 3,566,846 $ 2,645,131 Floating Rate Debt: 10 East 53rd Street (5) February 2017 2.98 % $ 125,000 $ 125,000 724 Fifth Avenue April 2017 2.90 % 275,000 275,000 1552 Broadway (6) April 2017 4.68 % 185,410 190,409 55 West 46th Street (7) October 2017 2.78 % 157,322 150,000 175-225 Third Street December 2017 4.51 % 40,000 40,000 Jericho Plaza (8) March 2018 4.64 % 76,993 163,750 605 West 42nd Street July 2018 2.91 % 539,000 — 650 Fifth Avenue (9) August 2018 4.10 % 77,500 65,000 280 Park Avenue June 2019 2.51 % 900,000 30,000 121 Greene Street November 2019 1.98 % 15,000 15,000 131-137 Spring Street August 2020 2.03 % 141,000 141,000 11 West 34th Street January 2021 1.93 % 23,000 23,000 100 Park Avenue February 2021 2.23 % 360,000 360,000 21 East 66th Street June 2033 3.00 % 1,726 1,805 Stonehenge Portfolio (10) Various 5.71 % 65,577 10,500 33 Beekman — 73,518 Total floating rate debt $ 2,982,528 $ 1,663,982 Total joint venture mortgages and other loans payable $ 6,549,374 $ 4,309,113 Deferred financing costs, net (95,408 ) (42,565 ) Total joint venture mortgages and other loans payable, net $ 6,453,966 $ 4,266,548 ____________________________________________________________________ (1) Effective weighted average interest rate for the year ended December 31, 2016 , taking into account interest rate hedges in effect during the period. (2) In January 2017, this loan was refinanced with a new $375.0 million mortgage, of which $340.0 million was drawn at closing, with a floating interest rate of LIBOR + 1.85% and a maturity date of January 2020. (3) These loans are comprised of a $300.0 million fixed rate mortgage loan and $355.3 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate. (4) Amount is comprised of $13.1 million , $34.5 million , $139.7 million , and $175.2 million in fixed-rate mortgages that mature in April 2017, November 2017, August 2019, and June 2024, respectively. (5) In February 2017, this loan was refinanced with a new $170.0 million mortgage with a floating interest rate of LIBOR + 2.25% and a maturity date of February 2020. (6) These loans are comprised of a $145.0 million mortgage loan and a $41.5 million mezzanine loan. As of December 31, 2016 , $0.6 million of the mortgage loan and $0.5 million of the mezzanine loan was unfunded. (7) This loan has a committed amount of $190.0 million , of which $32.7 million was unfunded as of December 31, 2016 . (8) We hold an 11.67% non-controlling interest in the joint venture and the property secures a two year $100.0 million loan, of which $77.0 million is currently outstanding. (9) This loan has a committed amount of $97.0 million , of which $19.5 million was unfunded as of December 31, 2016 . (10) Amount is comprised of $55.3 million and $10.2 million in floating-rate mortgages that mature in June 2017 and December 2017, respectively.
Schedule of combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at December 31, 2016 and 2015 , are as follows (in thousands): December 31, 2016 December 31, 2015 Assets Commercial real estate property, net $ 9,131,717 $ 6,122,468 Cash and restricted cash 328,455 258,564 Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance 232,778 208,802 Debt and preferred equity investments, net 336,164 145,878 Other assets 683,481 248,474 Total assets $ 10,712,595 $ 6,984,186 Liabilities and members' equity Mortgages and other loans payable, net $ 6,453,966 $ 4,266,548 Deferred revenue/gain 356,414 209,095 Other liabilities 391,500 314,065 Members' equity 3,510,715 2,194,478 Total liabilities and members' equity $ 10,712,595 $ 6,984,186 Company's investments in unconsolidated joint ventures $ 1,890,186 $ 1,203,858
Schedule of combined statements of income for the unconsolidated joint ventures	The combined statements of operations for the unconsolidated joint ventures, from acquisition date through the years ended December 31, 2016 , 2015 , and 2014 are as follows (in thousands): Year Ended December 31, 2016 2015 2014 Total revenues $ 712,689 $ 576,845 $ 522,132 Operating expenses 126,913 106,613 82,436 Ground rent 14,924 14,083 9,898 Real estate taxes 111,673 89,734 64,217 Interest expense, net of interest income 197,741 199,126 178,743 Amortization of deferred financing costs 24,829 13,394 12,395 Transaction related costs 5,566 615 535 Depreciation and amortization 199,011 149,023 137,793 Total expenses $ 680,657 $ 572,588 $ 486,017 Loss on early extinguishment of debt (1,606 ) (1,089 ) (6,743 ) Net income before gain on sale $ 30,426 $ 3,168 $ 29,372 Company's equity in net income from unconsolidated joint ventures $ 11,874 $ 13,028 $ 26,537

Deferred Costs (Tables)

Deferred Costs (Tables)	12 Months Ended
	Dec. 31, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of components of deferred costs	Deferred costs at December 31, 2016 and 2015 consisted of the following (in thousands): December 31, 2016 2015 Deferred leasing costs $ 468,971 $ 415,406 Less: accumulated amortization (201,371 ) (175,486 ) Deferred costs, net $ 267,600 $ 239,920

Mortgages and Other Loans Pay46

Mortgages and Other Loans Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Mortgages and Other Loans Payable
Schedule of first mortgages and other loans payable collateralized by the respective properties and assignment of leases	The first mortgages and other loans payable collateralized by the respective properties and assignment of leases at December 31, 2016 and 2015 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 31, 2016 December 31, 2015 Fixed Rate Debt: FHLBNY Facility (2) January 2017 1.03 % $ 105,000 $ — FHLBNY Facility (2) January 2017 0.80 % 100,000 — 485 Lexington Avenue (3) February 2017 5.61 % 450,000 450,000 762 Madison Avenue (4) February 2017 3.86 % 7,694 7,872 Unsecured Loan June 2018 4.81 % 16,000 16,000 One Madison Avenue May 2020 5.91 % 517,806 542,817 100 Church Street July 2022 4.68 % 221,446 225,099 919 Third Avenue (5) June 2023 5.12 % 500,000 500,000 420 Lexington Avenue October 2024 3.99 % 300,000 300,000 1515 Broadway March 2025 3.93 % 888,531 900,000 400 East 58th Street (6) November 2026 3.00 % 40,000 28,990 Landmark Square January 2027 5.05 % 100,000 79,562 Series J Preferred Units (7) April 2051 3.75 % 4,000 4,000 885 Third Avenue (8) 6.26 % 267,650 267,650 400 East 57th Street (9) — 67,644 11 Madison Avenue (10) — 1,400,000 388-390 Greenwich Street (11) — 1,004,000 500 West Putnam Avenue (12) — 22,376 Total fixed rate debt $ 3,518,127 $ 5,816,010 Floating Rate Debt: 719 Seventh Avenue February 2018 3.55 % $ 37,388 $ — 183, 187 Broadway & 5-7 Dey Street May 2018 3.16 % 58,000 40,000 Master Repurchase Agreement July 2018 3.04 % 184,642 253,424 1080 Amsterdam (13) November 2018 4.23 % 3,525 3,525 220 East 42nd Street October 2020 2.08 % 275,000 275,000 One Vanderbilt Avenue (14) September 2021 4.09 % 64,030 — FHLBNY Facility — 45,750 600 Lexington Avenue — 112,795 388-390 Greenwich Street (11) — 446,000 248-252 Bedford Avenue (15) — 29,000 Total floating rate debt $ 622,585 $ 1,205,494 Total fixed rate and floating rate debt $ 4,140,712 $ 7,021,504 Mortgages reclassed to liabilities related to assets held for sale (15) — (29,000 ) Total mortgages and other loans payable $ 4,140,712 $ 6,992,504 Deferred financing costs, net of amortization (66,882 ) (110,584 ) Total mortgages and other loans payable, net $ 4,073,830 $ 6,881,920 ____________________________________________________________________ (1) Effective weighted average interest rate for the year ended December 31, 2016 , taking into account interest rate hedges in effect during the period. (2) The facility was repaid in January 2017. (3) In January 2017, this loan was refinanced with a new $450.0 million mortgage with a fixed effective interest rate of 4.22% and a maturity date of February 2027. (4) In February 2017, the mortgage was repaid. (5) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan. (6) The loan carries a fixed interest rate of 3.00% for the first 5 years and is prepayable without penalty in year 5 . (7) In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million , 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000 per unit. The Series J Preferred Units are accounted for as debt because they can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement. (8) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and as a result, the property remains on our consolidated balance sheet until the criteria is met. The maturity date of the mortgage on the property, which was assumed by the buyer, is July 2017. (9) In October 2016, we closed on the sale of a 49.0% interest on 400 East 57th Street. This property is now classified as an unconsolidated joint venture. (10) In August 2016, we closed on the sale of a 40.0% interest on 11 Madison Avenue. This property is now classified as an unconsolidated joint venture. (11) In June 2016, we closed on the sale of 388-390 Greenwich Street. (12) In January 2016, the mortgage was repaid. (13) In January 2017, this loan was refinanced with a new $47.0 million facility with a maturity date of January 2027. (14) In September 2016, we closed on a $1.5 billion construction facility in connection with the development of One Vanderbilt Avenue. This facility bears interest at 350 basis points over 30-day LIBOR, with reductions based on meeting certain conditions, and has an initial five -year term with two one -year extension options. Advances under the loan are subject to incurred costs, funded equity, loan to value thresholds, and entering into construction contracts. (15) This property at 248-252 Bedford Avenue in Brooklyn, New York was sold in February 2016. At December 31, 2015, this property was held for sale and the related mortgage, net of deferred financing, net of amortization costs of $0.6 million , was included in liabilities related to assets held for sale.

Corporate Indebtedness (Tables)

Corporate Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of senior unsecured notes and other related disclosures by scheduled maturity date	The following table sets forth our senior unsecured notes and other related disclosures as of December 31, 2016 and 2015 , respectively, by scheduled maturity date (dollars in thousands): Issuance December 31, 2016 Unpaid Principal Balance December 31, 2016 Accreted Balance December 31, 2015 Accreted Balance Coupon Rate (1) Effective Rate Term (in Years) Maturity Date October 12, 2010 (2) $ 345,000 $ 334,077 $ 321,130 3.00 % 3.00 % 7 October 2017 August 5, 2011 (3) 250,000 249,880 249,810 5.00 % 5.00 % 7 August 2018 March 16, 2010 (3) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (3) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (3) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 March 26, 2007 (4) — — 10,008 March 31, 2006 (5) — — 255,296 $ 1,145,000 $ 1,133,957 $ 1,386,244 Deferred financing costs, net (5,642 ) (7,280 ) $ 1,145,000 $ 1,128,315 $ 1,378,964 ____________________________________________________________________ (1) Interest on the senior unsecured notes is payable semi-annually with principal and unpaid interest due on the scheduled maturity dates. (2) Issued by the Operating Partnership. Interest on these exchangeable notes is payable semi-annually on April 15 and October 15. The notes had an initial exchange rate representing an exchange price that was set at a 30.0% premium to the last reported sale price of SL Green's common stock on October 6, 2010, or $85.81 . The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 12.6478 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. As a result of meeting specified events (as defined in the Indenture Agreement), these notes became exchangeable commencing January 1, 2016 and will remain exchangeable through March 31, 2016. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of December 31, 2016 , $10.9 million remained to be amortized into the debt balance. (3) Issued by the Company, the Operating Partnership and ROP, as co-obligors. (4) Balance was repaid in September 2016. (5) Issued by ROP, balance was repaid in March 2016.
Schedule of combined aggregate principal maturities	Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of December 31, 2016 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Amortization Principal Revolving Credit Facility Unsecured Term Loan Trust Preferred Securities Senior Unsecured Notes Total Joint Venture Debt 2017 $ 51,531 $ 930,329 $ — $ — $ — $ 345,000 $ 1,326,860 $ 574,327 2018 54,371 299,555 — — — 250,000 603,926 48,253 2019 58,916 — — 1,183,000 — — 1,241,916 555,545 2020 40,700 679,531 — — — 250,000 970,231 31,183 2021 29,666 64,030 — — — — 93,696 222,452 Thereafter 86,275 1,845,808 — — 100,000 300,000 2,332,083 1,311,022 $ 321,459 $ 3,819,253 $ — $ 1,183,000 $ 100,000 $ 1,145,000 $ 6,568,712 $ 2,742,782
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Year Ended December 31, 2016 2015 2014 Interest expense before capitalized interest $ 348,062 $ 357,926 $ 342,648 Interest capitalized (24,067 ) (31,108 ) (22,750 ) Interest income (2,796 ) (2,948 ) (2,498 ) Interest expense, net $ 321,199 $ 323,870 $ 317,400

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of amounts due from/to related parties	Amounts due from related parties at December 31, 2016 and 2015 consisted of the following (in thousands): December 31, 2016 2015 Due from joint ventures $ 1,240 $ 1,334 Other 14,616 9,316 Related party receivables $ 15,856 $ 10,650

Noncontrolling Interests on t49

Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interest	Below is the rollforward analysis of the activity relating to the noncontrolling interests in the Operating Partnership as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Balance at beginning of period $ 424,206 $ 469,524 Distributions (12,671 ) (9,710 ) Issuance of common units 78,495 30,506 Redemption of common units (31,805 ) (55,697 ) Net income 10,136 10,565 Accumulated other comprehensive income allocation 1,299 (67 ) Fair value adjustment 4,222 (20,915 ) Balance at end of period $ 473,882 $ 424,206
Schedule of Preferred Unit Activity	Below is the rollforward analysis of the activity relating to the preferred units in the Operating Partnership as of December 31, 2016 and 2015 (in thousands): December 31, 2016 2015 Balance at beginning of period $ 282,516 $ 71,115 Issuance of preferred units 22,793 211,601 Redemption of preferred units (3,299 ) (200 ) Balance at end of period $ 302,010 $ 282,516

Stockholders' Equity of the C50

Stockholders' Equity of the Company (Tables)	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments	The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the year ended December 31, 2016 , 2015, and 2014, respectively (in thousands): Year Ended December 31, 2016 2015 2014 Common Stock Shares Issued 2,687 775,760 608 Dividend reinvestments/stock purchases under the DRSPP $ 277 $ 99,555 $ 64
Schedule of Earnings Per Share	SL Green's earnings per share for the years ended December 31, 2016 , 2015 , and 2014 are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic Earnings: Income attributable to SL Green common stockholders $ 234,946 $ 269,132 $ 503,104 Effect of Dilutive Securities: Redemption of units to common shares 10,136 10,565 18,467 Diluted Earnings: Income attributable to SL Green common stockholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic Shares: Weighted average common stock outstanding 100,185 99,345 95,774 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,323 3,899 3,514 Stock-based compensation plans 373 490 408 Diluted weighted average common stock outstanding 104,881 103,734 99,696

Partners' Capital of the Oper51

Partners' Capital of the Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Schedule of calculation of numerator and denominator in earnings per unit	The Operating Partnership's earnings per unit for the years ended December 31, 2016 , 2015 , and 2014 respectively are computed as follows (in thousands): Year Ended December 31, Numerator 2016 2015 2014 Basic and Diluted Earnings: Income attributable to SLGOP common unitholders $ 245,082 $ 279,697 $ 521,571 Year Ended December 31, Denominator 2016 2015 2014 Basic units: Weighted average common units outstanding 104,508 103,244 99,288 Effect of Dilutive Securities: Stock-based compensation plans 373 490 408 Diluted weighted average common units outstanding 104,881 103,734 99,696

Share-based Compensation (Table

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of weighted average assumptions used to estimate the grant date fair value of options granted	A summary of the Company's restricted stock as of December 31, 2016 , 2015 , and 2014 and charges during the years ended December 31, 2016 , 2015 , and 2014 are as follows: 2016 2015 2014 Balance at beginning of year 3,137,881 3,000,979 2,994,197 Granted 98,800 143,053 9,550 Cancelled (34,650 ) (6,151 ) (2,768 ) Balance at end of year 3,202,031 3,137,881 3,000,979 Vested during the year 83,822 87,081 75,043 Compensation expense recorded $ 7,153,966 $ 7,540,747 $ 9,658,019 Weighted average fair value of restricted stock granted during the year $ 10,650,077 $ 16,061,201 $ 1,141,675 The fair value of each stock option or Class O LTIP Unit granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information with the following weighted average assumptions for grants during the years ended December 31, 2016 , 2015 , and 2014 . 2016 2015 2014 Dividend yield 2.37 % 1.97 % 1.60 % Expected life 3.7 years 3.6 years 3.6 years Risk-free interest rate 1.57 % 1.43 % 1.29 % Expected stock price volatility 26.76 % 32.34 % 33.97 %
Summary of the status of stock options and changes during the period	A summary of the status of the Company's stock options as of December 31, 2016 , 2015 , and 2014 and changes during the years ended December 31, 2016 , 2015 , and 2014 are as follows: 2016 2015 2014 Options Outstanding Weighted Average Exercise Price Options Outstanding Weighted Average Exercise Price Options Weighted Balance at beginning of year $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 $ 1,765,034 $ 83.24 Granted 445,100 105.86 389,836 112.54 102,050 119.12 Exercised (192,875 ) 76.90 (217,438 ) 74.69 (348,156 ) 72.76 Lapsed or cancelled (110,019 ) 123.86 (40,117 ) 98.61 (56,202 ) 90.03 Balance at end of year $ 1,737,213 $ 98.44 $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 Options exercisable at end of year 748,617 $ 87.72 589,055 $ 89.85 $ 428,951 $ 90.32 Weighted average fair value of options granted during the year $ 8,363,036 $ 9,522,613 $ 2,841,678

Accumulated Other Comprehensi53

Accumulated Other Comprehensive Loss(Tables)	12 Months Ended
	Dec. 31, 2016
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) [Line Items]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2016 , 2015 and 2014 (in thousands): Net unrealized (loss) gain on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized (loss) gain on derivative instruments ( 2 ) Unrealized gain (loss) on marketable securities Total Balance at December 31, 2013 $ (15,125 ) $ (4,870 ) $ 4,784 $ (15,211 ) Other comprehensive (loss) income before reclassifications (576 ) 2,847 (2,692 ) (421 ) Amounts reclassified from accumulated other comprehensive income 6,203 1,928 521 8,652 Balance at December 31, 2014 (9,498 ) (95 ) 2,613 (6,980 ) Other comprehensive loss before reclassifications (11,143 ) (1,714 ) (610 ) (13,467 ) Amounts reclassified from accumulated other comprehensive income 10,481 1,217 — 11,698 Balance at December 31, 2015 (10,160 ) (592 ) 2,003 (8,749 ) Other comprehensive income before reclassifications 13,534 1,160 3,517 18,211 Amounts reclassified from accumulated other comprehensive income 9,222 3,453 — 12,675 Balance at December 31, 2016 $ 12,596 $ 4,021 $ 5,520 $ 22,137 ____________________________________________________________________ (1) Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of operations. As of December 31, 2016 and 2015 , the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive income (loss) relating to net unrealized loss on derivative instrument, was $7.1 million and $9.7 million , respectively. (2) Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of operations.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2016 and 2015 (in thousands): December 31, 2016 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 85,110 $ 48,315 $ 36,795 $ — Interest rate cap and swap agreements (included in other assets) $ 21,090 $ — $ 21,090 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 1 $ — $ 1 $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 45,138 $ 4,704 $ 40,434 $ — Interest rate cap and swap agreements (included in other assets) $ 204 $ — $ 204 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 10,776 $ — $ 10,776 $ —
Fair Value, by Balance Sheet Grouping	The following table provides the carrying value and fair value of these financial instruments as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,640,412 (2) $ 1,670,020 (2) Fixed rate debt $ 5,452,084 $ 5,722,494 $ 7,232,254 $ 7,591,388 Variable rate debt (3) 1,105,585 1,110,110 3,202,494 3,179,186 $ 6,557,669 $ 6,832,604 $ 10,434,748 $ 10,770,574 ____________________________________________________________________ (1) Amounts exclude net deferred financing costs. (2) At December 31, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.6 billion and $1.8 billion . At December 31, 2015 , debt and preferred equity investments had an estimated fair value ranging between $1.7 billion and $1.8 billion .

Financial Instruments_ Deriva55

Financial Instruments: Derivatives and Hedging (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of notional and fair value of derivative financial instruments and foreign currency hedges	The following table summarizes the notional value at inception and fair value of our consolidated derivative financial instruments at December 31, 2016 based on Level 2 information. The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks (amounts in thousands). Notional Value Strike Rate Effective Date Expiration Date Balance Sheet Location Fair Value Interest Rate Swap $ 200,000 0.938 % October 2014 December 2017 Other Assets $ 11 Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Assets 5 Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Assets 5 Interest Rate Swap 14,409 0.500 % January 2015 January 2017 Other Assets 2 Interest Rate Swap 8,018 0.852 % February 2015 February 2017 Other Liabilities (1 ) Interest Rate Cap 137,500 4.000 % September 2015 September 2017 Other Assets — Interest Rate Cap 1,450,000 4.750 % May 2016 May 2017 Other Assets — Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Assets 10,293 Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Assets 4,963 Interest Rate Cap 23,199 4.500 % October 2016 October 2017 Other Assets — Interest Rate Swap 5,000 2.160 % December 2016 December 2026 Other Assets 77 Interest Rate Swap 225,000 2.185 % January 2017 January 2027 Other Assets 3,223 Interest Rate Swap 25,000 2.185 % January 2017 January 2027 Other Assets 358 Interest Rate Swap 150,000 2.183 % January 2017 January 2027 Other Assets 2,153 $ 21,089
Schedule of effect of derivative financial instruments on consolidated statements of income	The following table presents the effect of our derivative financial instruments and our share of our joint ventures' derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the years ended December 31, 2016 , 2015 , and 2014 , respectively (in thousands): Amount of (Loss) Gain Recognized in Other Comprehensive Loss (Effective Portion) Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location of (Loss) or Gain Recognized in Income on Derivative Amount of (Loss) or Gain Recognized into Income (Ineffective Portion) Year Ended Year Ended Year Ended Derivative 2016 2015 2014 2016 2015 2014 2016 2015 2014 Interest Rate Swaps/Caps $ 14,616 $ (11,607 ) $ (703 ) Interest expense $ 9,521 $ 10,892 $ 6,431 Interest expense $ (28 ) $ (422 ) $ 4 Share of unconsolidated joint ventures' derivative instruments 2,012 (1,779 ) 2,916 Equity in net income from unconsolidated joint ventures 1,981 1,265 1,999 Equity in net income from unconsolidated joint ventures 785 (19 ) — $ 16,628 $ (13,386 ) $ 2,213 $ 11,502 $ 12,157 $ 8,430 $ 757 $ (441 ) $ 4

Rental Income (Tables)

Rental Income (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Schedule of approximate future minimum rents to be received over the next five years and thereafter	Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2016 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands): Consolidated Properties Unconsolidated Properties 2017 $ 1,271,232 $ 198,304 2018 1,256,047 203,934 2019 1,161,772 195,888 2020 1,120,476 190,139 2021 976,638 184,367 Thereafter 8,062,838 1,389,446 $ 13,849,003 $ 2,362,078

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of contributions made to multi-employer plans	an. Contributions we made to the multi-employer plans for the years ended December 31, 2016 , 2015 and 2014 are included in the table below (in thousands

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of December 31, 2016 (in thousands): Capital lease Non-cancellable operating leases 2017 $ 2,387 $ 31,049 2018 2,387 31,049 2019 2,411 31,066 2020 2,620 31,436 2021 2,794 31,628 Thereafter 822,688 732,724 Total minimum lease payments $ 835,287 $ 888,952 Less amount representing interest (793,155 ) Capital lease obligations $ 42,132
Schedule of Future Minimum Lease Payments for Capital Leases	The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of December 31, 2016 (in thousands): Capital lease Non-cancellable operating leases 2017 $ 2,387 $ 31,049 2018 2,387 31,049 2019 2,411 31,066 2020 2,620 31,436 2021 2,794 31,628 Thereafter 822,688 732,724 Total minimum lease payments $ 835,287 $ 888,952 Less amount representing interest (793,155 ) Capital lease obligations $ 42,132

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected results of operations for the years ended December 31, 2016 , 2015 , and 2014 , and selected asset information as of December 31, 2016 and 2015 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues Years ended: December 31, 2016 $ 1,629,919 $ 234,062 $ 1,863,981 December 31, 2015 1,465,881 196,948 1,662,829 December 31, 2014 1,320,777 199,201 1,519,978 Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and (loss) gain on sale of marketable securities Years ended: December 31, 2016 $ (203,988 ) $ 211,244 $ 7,256 December 31, 2015 (78,681 ) 168,970 90,289 December 31, 2014 31,805 169,695 201,500 Total assets As of: December 31, 2016 $ 13,868,085 $ 1,989,702 $ 15,857,787 December 31, 2015 17,765,854 1,961,792 19,727,646
Schedule of reconciliation of income from continuing operations to net income attributable to SL Green common stockholders	The table below reconciles income from continuing operations to net income for the years ended December 31, 2016 , 2015 , and 2014 (in thousands): Year ended December 31, 2016 2015 2014 Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and loss (gain) on sale of marketable securities $ 7,256 $ 90,289 $ 201,500 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 44,009 15,844 123,253 Purchase price fair value adjustment — 40,078 67,446 Gain on sale of real estate, net 238,116 175,974 — Depreciable real estate reserves (10,387 ) (19,226 ) — Loss on early extinguishment of debt — (49 ) (32,365 ) (Loss) gain on sale of investment in marketable securities (83 ) — 3,895 Income from continuing operations 278,911 302,910 363,729 Net income from discontinued operations — 427 19,075 Gain on sale of discontinued operations — 14,122 163,059 Net income $ 278,911 $ 317,459 $ 545,863

Quarterly Financial Data of t60

Quarterly Financial Data of the Company (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
SL Green Realty Corp
Condensed Income Statements, Captions [Line Items]
Schedule of Quarterly Financial Information	Summarized quarterly financial data for the years ended December 31, 2016 and 2015 , which is reflective of the reclassification of the properties sold or held for sale during 2015 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts): 2016 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 374,242 $ 416,681 $ 617,614 $ 455,444 Income (loss) from continuing operations before equity in net (loss) income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves and loss on sale of marketable securities $ 26,278 $ 46,689 $ (76,304 ) $ (1,281 ) Equity in net (loss) income from unconsolidated joint ventures (95 ) (3,968 ) 5,841 10,096 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 421 225 33,448 9,915 Gain on sale of real estate 27,366 397 196,580 13,773 Depreciable real estate reserves — — (10,387 ) — Loss on the sale of investment in marketable securities — — (83 ) — Noncontrolling interests and preferred unit distributions (6,217 ) (5,353 ) (11,901 ) (5,544 ) Net income attributable to SL Green 47,753 37,990 137,194 26,959 Perpetual preferred stock dividends (3,737 ) (3,738 ) (3,737 ) (3,738 ) Net income attributable to SL Green common stockholders $ 44,016 $ 34,252 $ 133,457 $ 23,221 Net income attributable to common stockholders per common share—basic $ 0.44 $ 0.34 $ 1.33 $ 0.23 Net income attributable to common stockholders per common share—diluted $ 0.44 $ 0.34 $ 1.33 $ 0.23 2015 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 425,390 $ 432,066 $ 409,074 $ 396,299 Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 54,591 $ 17,367 $ (32,942 ) $ 38,245 Equity in net income from unconsolidated joint ventures 2,377 3,627 2,994 4,030 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (206 ) 15,281 769 — Purchase price fair value adjustment 40,078 — — — Gain on sale of real estate 16,270 159,704 — — Depreciable real estate reserves — (19,226 ) — — Loss on early extinguishment of debt — — — (49 ) Net income from discontinued operations — — — 427 Gain on sale of discontinued operations 1,139 — — 12,983 Noncontrolling interests and preferred unit distributions (9,208 ) (9,357 ) (6,189 ) (8,621 ) Net income (loss) attributable to SL Green 105,041 167,396 (35,368 ) 47,015 Perpetual preferred stock dividends (3,738 ) (3,738 ) (3,738 ) (3,738 ) Net income (loss) attributable to SL Green common stockholders $ 101,303 $ 163,658 $ (39,106 ) $ 43,277 Net income (loss) attributable to common stockholders per common share—basic $ 1.02 $ 1.64 $ (0.39 ) $ 0.44 Net income (loss) attributable to common stockholders per common share—diluted $ 1.01 $ 1.64 $ (0.39 ) $ 0.44

Quarterly Financial Data of t61

Quarterly Financial Data of the Operating Partnership (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
SL Green Operating Partnership
Condensed Income Statements, Captions [Line Items]
Schedule of Quarterly Financial Information	Summarized quarterly financial data for the years ended December 31, 2016 and 2015 , which is reflective of the reclassification of the properties sold or held for sale during 2015 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts): 2016 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 374,242 $ 416,681 $ 617,614 $ 455,444 Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 26,278 $ 46,689 $ (76,304 ) $ (1,281 ) Equity in net income (loss) from unconsolidated joint ventures (95 ) (3,968 ) 5,841 10,096 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 421 225 33,448 9,915 Gain on sale of real estate 27,366 397 196,580 13,773 Depreciable real estate reserves — — (10,387 ) — Loss on the sale of investment in marketable securities — (83 ) Noncontrolling interests and preferred unit distributions (4,252 ) (3,690 ) (6,315 ) (4,622 ) Net income attributable to SLGOP 49,718 39,653 142,780 27,881 Perpetual preferred units distributions (3,737 ) (3,738 ) (3,737 ) (3,738 ) Net income attributable to SLGOP common unitholders $ 45,981 $ 35,915 $ 139,043 $ 24,143 Net income attributable to common unitholders per common unit—basic $ 0.44 $ 0.34 $ 1.33 $ 0.23 Net income attributable to common unitholders per common unit—diluted $ 0.44 $ 0.34 $ 1.33 $ 0.23 2015 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 425,390 $ 432,066 $ 409,074 $ 396,299 Income (loss) 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, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and loss on early extinguishment of debt $ 54,591 $ 17,367 $ (32,942 ) $ 38,245 Equity in net income from unconsolidated joint ventures 2,377 3,627 2,994 4,030 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (206 ) 15,281 769 — Purchase price fair value adjustment 40,078 — — — Gain on sale of real estate 16,270 159,704 — — Depreciable real estate reserves — (19,226 ) — — Loss on early extinguishment of debt — — — (49 ) Net income from discontinued operations — — — 427 Gain on sale of discontinued operations 1,139 — — 12,983 Noncontrolling interests and preferred unit distributions (5,277 ) (2,890 ) (7,766 ) (6,878 ) Net income (loss) attributable to SLGOP 108,972 173,863 (36,945 ) 48,758 Perpetual preferred distributions (3,738 ) (3,738 ) (3,738 ) (3,738 ) Net income attributable to SLGOP common unitholders $ 105,234 $ 170,125 $ (40,683 ) $ 45,020 Net income attributable to common unitholders per common unit—basic $ 1.02 $ 1.64 $ (0.39 ) $ 0.44 Net income attributable to common unitholders per common unit—diluted $ 1.01 $ 1.64 $ (0.39 ) $ 0.44

Organization and Basis of Pre62

Organization and Basis of Presentation (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016
Organization
Number of shares to be received on redemption of one unit of limited partnership interests (shares)		1
SL Green Operating Partnership
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)		100.00%
Noncontrolling interest in the operating partnership (as a percent)		4.16%
SL Green Operating Partnership | Service Corporation
Organization
Economic interest in variable interest entity (as a percent)		95.00%
Subsequent Event | One Vanderbilt | National Pension Service of Korea
Organization
Ownership percentage in disposed asset	27.60%
Subsequent Event | One Vanderbilt | Hines Interest LP
Organization
Ownership percentage in disposed asset	1.40%
Subsequent Event | One Vanderbilt | National Pension Service of Korea and Hines Interest LP
Organization
Aggregate equity committed from partners	$ 525,000,000
Subsequent Event | 520 White Plains Road
Organization
Agreed sale consideration	21,000,000
Impairment Charge	$ 11,100,000

Organization and Basis of Pre63

Organization and Basis of Presentation (Schedule of Commercial Office Properties)(Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)ft²buildingshares	Dec. 31, 2015USD ($)
Real estate properties
Number of Properties | building	109
Approximate Square Feet unaudited (sqft)	32,922,082
Mortgage Loans on Real Estate, Commercial and Consumer, Net Including Debt Investments, Other | $	$ 2,000,000
Weighted Average Occupancy unaudited (as a percent)	90.60%
Debt and preferred equity investments | $	$ 1,640,412	$ 1,670,020
Debt Investments, Other | $	$ 300,000
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares	1
Commercial properties
Real estate properties
Number of Properties | building	88
Approximate Square Feet unaudited (sqft)	29,202,213
Weighted Average Occupancy unaudited (as a percent)	91.50%
Residential
Real estate properties
Number of Properties | building	21
Approximate Square Feet unaudited (sqft)	3,719,869
Weighted Average Occupancy unaudited (as a percent)	83.80%
Managed office properties
Real estate properties
Approximate Square Feet unaudited (sqft)	336,000
Consolidated properties
Real estate properties
Number of Properties | building	68
Approximate Square Feet unaudited (sqft)	21,330,769
Consolidated properties | Commercial properties
Real estate properties
Number of Properties | building	65
Approximate Square Feet unaudited (sqft)	20,858,664
Consolidated properties | Residential
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	472,105
Unconsolidated properties
Real estate properties
Number of Properties | building	41
Approximate Square Feet unaudited (sqft)	11,591,313
Unconsolidated properties | Commercial properties
Real estate properties
Number of Properties | building	23
Approximate Square Feet unaudited (sqft)	8,343,549
Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	18
Approximate Square Feet unaudited (sqft)	3,247,764
Manhattan
Real estate properties
Number of Properties | building	58
Approximate Square Feet unaudited (sqft)	24,395,413
Weighted Average Occupancy unaudited (as a percent)	93.20%
Manhattan | Office
Real estate properties
Number of Properties | building	31
Approximate Square Feet unaudited (sqft)	22,612,745
Weighted Average Occupancy unaudited (as a percent)	94.90%
Manhattan | Retail
Real estate properties
Number of Properties | building	19
Approximate Square Feet unaudited (sqft)	766,063
Weighted Average Occupancy unaudited (as a percent)	85.60%
Manhattan | Development/Redevelopment
Real estate properties
Number of Properties | building	6
Approximate Square Feet unaudited (sqft)	813,149
Weighted Average Occupancy unaudited (as a percent)	52.30%
Manhattan | Fee Interest
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	203,456
Weighted Average Occupancy unaudited (as a percent)	100.00%
Manhattan | Residential
Real estate properties
Number of Properties | building	21
Approximate Square Feet unaudited (sqft)	3,719,869
Weighted Average Occupancy unaudited (as a percent)	83.80%
Manhattan | Consolidated properties
Real estate properties
Number of Properties | building	38
Approximate Square Feet unaudited (sqft)	16,691,864
Manhattan | Consolidated properties | Office
Real estate properties
Number of Properties | building	24
Approximate Square Feet unaudited (sqft)	16,054,606
Manhattan | Consolidated properties | Retail
Real estate properties
Number of Properties | building	10
Approximate Square Feet unaudited (sqft)	418,093
Manhattan | Consolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	42,635
Manhattan | Consolidated properties | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	176,530
Manhattan | Consolidated properties | Residential
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	472,105
Manhattan | Consolidated properties | Dual property type, retail portion
Real estate properties
Approximate Square Feet unaudited (sqft)	270,132
Manhattan | Consolidated properties | Dual property type, residential portion
Real estate properties
Approximate Square Feet unaudited (sqft)	222,855
Manhattan | Unconsolidated properties
Real estate properties
Number of Properties | building	20
Approximate Square Feet unaudited (sqft)	7,703,549
Manhattan | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	7
Approximate Square Feet unaudited (sqft)	6,558,139
Manhattan | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft)	347,970
Manhattan | Unconsolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	770,514
Manhattan | Unconsolidated properties | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	26,926
Manhattan | Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	18
Approximate Square Feet unaudited (sqft)	3,247,764
Suburban
Real estate properties
Number of Properties | building	30
Approximate Square Feet unaudited (sqft)	4,806,800
Weighted Average Occupancy unaudited (as a percent)	82.80%
Suburban | Office
Real estate properties
Number of Properties | building	27
Approximate Square Feet unaudited (sqft)	4,753,800
Weighted Average Occupancy unaudited (as a percent)	82.60%
Suburban | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	52,000
Weighted Average Occupancy unaudited (as a percent)	100.00%
Suburban | Development/Redevelopment
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	1,000
Weighted Average Occupancy unaudited (as a percent)	100.00%
Suburban | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Weighted Average Occupancy unaudited (as a percent)	0.00%
Suburban | Consolidated properties
Real estate properties
Number of Properties | building	27
Approximate Square Feet unaudited (sqft)	4,166,800
Suburban | Consolidated properties | Office
Real estate properties
Number of Properties | building	25
Approximate Square Feet unaudited (sqft)	4,113,800
Suburban | Consolidated properties | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	52,000
Suburban | Consolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	1,000
Suburban | Consolidated properties | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	640,000
Suburban | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	640,000
Suburban | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0

Significant Accounting Polici64

Significant Accounting Policies (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Principles of Consolidation
Commercial real estate properties	$ 10,478,638	$ 14,620,896
Mortgages and other loans payable, net	4,073,830	6,881,920
Assets held for sale	0	34,981
Liabilities related to assets held for sale	0	29,000
Consolidated VIEs
Principles of Consolidation
Commercial real estate properties	1,700,000	200,700
Mortgages and other loans payable, net	$ 621,800	$ 101,100

Significant Accounting Polici65

Significant Accounting Policies (Investments in Commercial Real Estate Properties)(Details) $ in Thousands	Nov. 30, 2015USD ($)	Apr. 30, 2014USD ($)	Dec. 31, 2015USD ($)	May 31, 2014USD ($)	Jun. 30, 2016USD ($)property	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)property	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Investment in Commercial Real Estate Properties
Depreciation expense (including amortization of the capital lease asset)								$ 783,500	$ 523,800	$ 338,800
Number of properties expected to be sold | property					1		2
Period from cessation of major construction to consider construction project as complete and available for occupancy, maximum (in years)								1 year
Weighted average amortization period for above-market leases (in years)								5 years 1 month 13 days
Weighted average amortization period for below-market leases (in years)								24 years 10 days
Weighted average amortization for in-place lease costs (in years)								9 years 11 months
Increase in rental revenue from amortization of acquired leases								$ 196,200	38,700	23,300
Reduction in interest expense from amortization of above-market rate mortgages								2,800	2,300	$ 5,000
Identified intangible assets (included in other assets):
Gross amount			$ 939,518			$ 939,518		651,099	939,518
Accumulated amortization			(403,747)			(403,747)		(410,930)	(403,747)
Net			535,771			535,771		240,169	535,771
Identified intangible liabilities (included in deferred revenue):
Gross amount			866,561			866,561		655,930	866,561
Accumulated amortization			(486,928)			(486,928)		(464,749)	(486,928)
Net			379,633			379,633		191,181	$ 379,633
Net intangible assets reclassed to assets held for sale								0
Net intangible liabilities reclassed to liabilities relates to assets held for sale								0
Other Identifiable Assets [Member]
Estimated annual amortization
2,017								24,801
2,018								17,600
2,019								14,780
2,020								12,742
2,021								8,986
Acquired above-market leases, net of acquired below-market leases
Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract]
2,017								(19,286)
2,018								(17,022)
2,019								(16,300)
2,020								(15,279)
2,021								$ (6,356)
600 Lexington Avenue
Investment in Commercial Real Estate Properties
Purchase price fair value adjustment realized	$ 40,078		$ 40,100
388-390 Greenwich Street
Investment in Commercial Real Estate Properties
Purchase price fair value adjustment realized		$ 71,446		$ 71,400
Maximum | Above-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								14 years
Maximum | Below-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								14 years
Maximum | In-place leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								14 years
Minimum | Above-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								1 year
Minimum | Below-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								1 year
Minimum | In-place leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)								1 year
Building (fee ownership)
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								40 years
Building (leasehold interest) | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								40 years
Furniture and fixtures | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								7 years
Furniture and fixtures | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								4 years
Building | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								40 years
Building | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)								3 years
140-150 Grand Street
Investment in Commercial Real Estate Properties
Impairment Charge					$ 10,400		$ 19,200	$ 19,200
885 Third Avenue
Investment in Commercial Real Estate Properties
Impairment Charge						$ 6,600
One Vanderbilt
Investment in Commercial Real Estate Properties
Depreciation expense (including amortization of the capital lease asset)								131,800
388-390 Greenwich Street
Investment in Commercial Real Estate Properties
Increase in rental revenue from amortization of acquired leases								$ 172,400

Significant Accounting Polici66

Significant Accounting Policies (Investment in Marketable Securities)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Investment in Marketable Securities
Marketable securities	$ 85,110		$ 45,138
Cost basis	36,000		38,700
Proceeds from sale of marketable securities	7,000
Realized gain (loss) on investment in marketable securities	100
Fair Value
Investment in Marketable Securities
Marketable securities	85,110		45,138
Equity marketable securities
Investment in Marketable Securities
Marketable securities		$ 48,315	4,704
Cost basis	$ 43,300		4,300
Mortgage-backed securities
Investment in Marketable Securities
Marketable securities		$ 36,795	$ 40,434

Significant Accounting Polici67

Significant Accounting Policies (Investments in Unconsolidated Joint Ventures/Deferred Lease Costs/Revenue Recognition/Income Taxes)(Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)joint_venture	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Deferred Lease Costs [Abstract]
Portion of compensation capitalized	$ 15.4	$ 15.4	$ 15.1
Estimated average lease term (in years)	7 years
Days past due for income recognition on debt and preferred equity investments to be suspended	90 days
Income taxes
Federal, state and local tax provision	$ 2.8	$ 3.1	$ 7.8
Joint venture
Schedule of Equity Method Investments [Line Items]
Number of joint ventures with performance guarantees under master leases | joint_venture	2

Significant Accounting Polici68

Significant Accounting Policies (Concentrations of Credit Risk/Reclassification)(Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)Tenantagreement	Dec. 31, 2015USD ($)	Dec. 31, 2014
Concentration of Credit Risk
Debt Issuance Costs, Net	$ 82,300	$ 130,300
Common shares	1,017	1,001
Additional paid-in-capital	5,624,545	5,439,735
Treasury shares	(124,049)	(10,000)
Retained earnings	$ 1,578,893	$ 1,643,546
Workforce concentration
Concentration of Credit Risk
Number of collective bargaining agreements | agreement	6
Annualized rent | Customer concentration
Concentration of Credit Risk
Number of tenants (tenants) | Tenant	2
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent) (more than)	5.00%
Annualized rent | 1515 Broadway | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	9.80%	10.20%	9.90%
Annualized rent | 388-390 Greenwich Street | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)		9.40%	9.80%
Annualized rent | 919 Third Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	8.10%	7.80%	7.50%
Annualized rent | 1185 Avenue of the Americas | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.60%	7.50%	7.80%
Annualized rent | 11 Madison Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)		7.50%
Annualized rent | 420 Lexington Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	6.50%	6.40%
Annualized rent | 1 Madison Ave | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	6.20%	5.70%
Annualized rent | 485 Lexington Avenue (3) | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	5.00%
Collective bargaining arrangements | Workforce concentration
Concentration of Credit Risk
Percentage of concentration (percent)	71.30%
Collective bargaining arrangements expiring in December 2019 | Workforce concentration
Concentration of Credit Risk
Percentage of concentration (percent)	71.10%

Significant Accounting Polici69

Significant Accounting Policies (Reclassification 2)(Details) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Debt Issuance Costs, Net	$ 82,300	$ 130,300
Limited partner interests in SLGOP	426,436	431,852
SL Green Operating Partnership
Error Corrections and Prior Period Adjustments Restatement [Line Items]
SL Green partner's capital	7,080,406	7,074,282
Partners' Capital	$ 7,750,911	$ 7,719,317	$ 7,459,216	$ 7,016,876
Common Stock | Partners' Interest | SL Green Operating Partnership
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Partners' Capital Account, Units	100,562	99,976	97,325	94,993
Partners' Capital	$ 7,080,406	$ 7,074,282	$ 6,722,422	$ 6,318,684

Property Acquisitions (Details)

Property Acquisitions (Details) - USD ($)	Nov. 30, 2015	Apr. 30, 2014	Mar. 31, 2016	Dec. 31, 2015	Aug. 31, 2015	Jul. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Oct. 31, 2014	Sep. 30, 2014	Jul. 31, 2014	May 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units				$ 221,932,000									$ 221,932,000	$ 221,932,000
Impact to rental revenue for amortization of aggregate below-market leases													1,323,767,000	1,245,981,000	$ 1,121,066,000
Impact to depreciation expense													821,041,000	560,887,000	$ 371,610,000
Total fixed rate debt				5,816,010,000									3,518,127,000	5,816,010,000
600 Lexington Ave [Member] | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land				97,000,000										97,000,000
Building and building leasehold				180,200,000										$ 180,200,000
183 Broadway [Member]
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land			$ 5,799,000
Building and building leasehold			23,431,000
Above market lease value			0
Acquired in-place leases			773,000
Other assets, net of other liabilities			20,000
Assets acquired			30,023,000
Mark-to-market assumed debt			0
Below market lease value			(1,523,000)
Derivatives			0
Liabilities assumed			(1,523,000)
Purchase price			28,500,000
Net consideration funded by us at closing, excluding consideration financed by debt			28,500,000
Equity and/or debt investment held			0
Debt assumed			0
Impact to rental revenue for amortization of aggregate below-market leases													200,000
Impact to depreciation expense													2,100,000
183 Broadway [Member] | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land			26,600,000
Building and building leasehold			$ 0
600 Lexington Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land													81,670,000
Building and building leasehold													182,447,000
Above market lease value													3,320,000
Acquired in-place leases													22,449,000
Other assets, net of other liabilities													0
Assets acquired													289,886,000
Mark-to-market assumed debt													(55,000)
Below market lease value													(5,831,000)
Derivatives													0
Liabilities assumed													(5,886,000)
Purchase price	$ 284,000,000												$ 284,000,000
Net consideration funded by us at closing, excluding consideration financed by debt	79,085,000			79,085,000
Equity and/or debt investment held	54,575,000			54,575,000
Debt assumed	112,795,000			112,795,000
Ownership interest in consolidated joint venture (as a percent)													45.00%
Value of interest													$ 277,300,000
Purchase price fair value adjustment	$ 40,078,000			$ 40,100,000
183, 187 Broadway & 5-7 Dey Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					$ 20,266,000
Building and building leasehold					42,468,000
Above market lease value					17,000
Acquired in-place leases					3,621,000
Other assets, net of other liabilities					0
Assets acquired					66,372,000
Mark-to-market assumed debt					0
Below market lease value					(3,226,000)
Derivatives					0
Liabilities assumed					(3,226,000)
Purchase price					63,146,000
Net consideration funded by us at closing, excluding consideration financed by debt					0
Equity and/or debt investment held					0
Debt assumed					0
183, 187 Broadway & 5-7 Dey Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					22,100,000
Building and building leasehold					41,000,000
183, 187 Broadway & 5-7 Dey Street | Series R Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units													10,000,000
183, 187 Broadway & 5-7 Dey Street | Series S Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units													26,900,000
11 Madison Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					675,776,000
Building and building leasehold					1,553,602,000
Above market lease value					19,764,000
Acquired in-place leases					366,949,000
Other assets, net of other liabilities					0
Assets acquired					2,616,091,000
Mark-to-market assumed debt					0
Below market lease value					(187,732,000)
Derivatives					0
Liabilities assumed					(187,732,000)
Purchase price					2,428,359,000
Net consideration funded by us at closing, excluding consideration financed by debt					0
Equity and/or debt investment held					0
Debt assumed					0
11 Madison Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					849,900,000
Building and building leasehold					$ 1,600,000,000
110 Greene Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land						$ 45,120,000
Building and building leasehold						215,470,000
Above market lease value						0
Acquired in-place leases						8,967,000
Other assets, net of other liabilities						0
Assets acquired						269,557,000
Mark-to-market assumed debt						0
Below market lease value						(14,557,000)
Derivatives						0
Liabilities assumed						(14,557,000)
Purchase price						255,000,000
Net consideration funded by us at closing, excluding consideration financed by debt						0
Equity and/or debt investment held						0
Debt assumed						$ 0
Ownership interest in consolidated joint venture (as a percent)						90.00%
110 Greene Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land						$ 89,300,000
Building and building leasehold						165,800,000
110 Greene Street | Series P Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units						5,000,000
110 Greene Street | Series Q Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units						$ 6,700,000
Upper East Side Residential
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land							$ 48,152,000
Building and building leasehold							0
Above market lease value							0
Acquired in-place leases							1,922,000
Other assets, net of other liabilities							0
Assets acquired							50,074,000
Mark-to-market assumed debt							0
Below market lease value							0
Derivatives							0
Liabilities assumed							0
Purchase price							50,074,000
Net consideration funded by us at closing, excluding consideration financed by debt							0
Equity and/or debt investment held							0
Debt assumed							$ 0
Ownership interest in consolidated joint venture (as a percent)							95.10%
Upper East Side Residential | Series N Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units							$ 13,800,000
1640 Flatbush Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land								$ 6,226,000
Building and building leasehold								501,000
Above market lease value								0
Acquired in-place leases								146,000
Other assets, net of other liabilities								0
Assets acquired								6,873,000
Mark-to-market assumed debt								0
Below market lease value								(73,000)
Derivatives								0
Liabilities assumed								(73,000)
Purchase price								6,800,000
Net consideration funded by us at closing, excluding consideration financed by debt								0
Equity and/or debt investment held								0
Debt assumed								0
1640 Flatbush Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land								6,100,000
Building and building leasehold								$ 700,000
102 Greene Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land									$ 8,215,000
Building and building leasehold									26,717,000
Above market lease value									0
Acquired in-place leases									1,015,000
Other assets, net of other liabilities									3,000
Assets acquired									35,950,000
Mark-to-market assumed debt									0
Below market lease value									(3,701,000)
Derivatives									0
Liabilities assumed									(3,701,000)
Purchase price									32,249,000
Net consideration funded by us at closing, excluding consideration financed by debt									32,249,000
Equity and/or debt investment held									0
Debt assumed									0
102 Greene Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land									11,300,000
Building and building leasehold									21,000,000
635 Madison Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land										$ 205,632,000
Building and building leasehold										15,805,000
Above market lease value										0
Acquired in-place leases										17,345,000
Other assets, net of other liabilities										0
Assets acquired										238,782,000
Mark-to-market assumed debt										0
Below market lease value										(85,036,000)
Derivatives										0
Liabilities assumed										(85,036,000)
Purchase price										153,746,000
Net consideration funded by us at closing, excluding consideration financed by debt										153,746,000
Equity and/or debt investment held										0
Debt assumed										0
635 Madison Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land										$ 153,700,000
719 Seventh Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land											$ 41,850,000
Building and building leasehold											0
Above market lease value											0
Acquired in-place leases											0
Other assets, net of other liabilities											0
Assets acquired											41,850,000
Mark-to-market assumed debt											0
Below market lease value											0
Derivatives											0
Liabilities assumed											0
Purchase price											41,850,000
Net consideration funded by us at closing, excluding consideration financed by debt											41,850,000
Equity and/or debt investment held											0
Debt assumed											$ 0
Ownership interest in consolidated joint venture (as a percent)											75.00%
719 Seventh Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land											$ 14,400,000
Building and building leasehold											26,700,000
719 Seventh Avenue | Series L Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units											14,100,000
719 Seventh Avenue | Series K Preferred Units
Recognized Identifiable Assets Acquired and Liabilities Assumed
Issuance of aggregate liquidation preference of preferred units											9,500,000
115 Spring Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land											11,078,000
Building and building leasehold											44,799,000
Above market lease value											0
Acquired in-place leases											2,037,000
Other assets, net of other liabilities											0
Assets acquired											57,914,000
Mark-to-market assumed debt											0
Below market lease value											(4,789,000)
Derivatives											0
Liabilities assumed											(4,789,000)
Purchase price											53,125,000
Net consideration funded by us at closing, excluding consideration financed by debt											53,125,000
Equity and/or debt investment held											0
Debt assumed											0
115 Spring Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land											15,900,000
Building and building leasehold											$ 37,200,000
388-390 Greenwich Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land												$ 516,292,000
Building and building leasehold												964,434,000
Above market lease value												0
Acquired in-place leases												302,430,000
Other assets, net of other liabilities												6,495,000
Assets acquired												1,789,651,000
Mark-to-market assumed debt												0
Below market lease value												(186,782,000)
Derivatives												(18,001,000)
Liabilities assumed												(204,783,000)
Purchase price		$ 1,585,000,000										1,584,868,000
Net consideration funded by us at closing, excluding consideration financed by debt		208,614,000										208,614,000
Equity and/or debt investment held		(148,025,000)										148,025,000
Debt assumed		1,162,379,000										1,162,379,000
Value of interest												1,585,000,000
Purchase price fair value adjustment		$ 71,446,000										$ 71,400,000
Economic interest (as a percent)												49.65%
Face amount of loan												$ 1,450,000,000
Notional value												504,000,000
Total fixed rate debt									$ 500,000,000
388-390 Greenwich Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land												558,700,000
Building and building leasehold												$ 1,000,000,000
102 Greene Street, 635 Madison Avenue, 719 Seventh Avenue, 115 Spring Street, and 388-390 Greenwich Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Impact to rental revenue for amortization of aggregate below-market leases													7,600,000
Impact to depreciation expense													$ 10,300,000

Property Acquisitions - Schedul

Property Acquisitions - Schedule of Fair Value of Equity Interest Immediately Before Acquisition Date (Details) - USD ($) $ in Thousands	Nov. 30, 2015	Apr. 30, 2014	Dec. 31, 2015	Aug. 31, 2015	Jul. 31, 2015	Mar. 31, 2015	May 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Property Acquisitions
Operating Leases, Income Statement, Minimum Lease Revenue								$ 1,323,767	$ 1,245,981	$ 1,121,066
Depreciation and amortization								821,041	560,887	$ 371,610
183, 187 Broadway & 5-7 Dey Street
Property Acquisitions
Land				$ 20,266
Building and building leasehold				42,468
Contract purchase price				63,146
Net consideration funded by us at closing, excluding consideration financed by debt				0
Debt assumed				0
Equity and/or debt investment held				0
600 Lexington Avenue
Property Acquisitions
Land								81,670
Building and building leasehold								182,447
Contract purchase price	$ 284,000							$ 284,000
Net consideration funded by us at closing, excluding consideration financed by debt	(79,085)		$ (79,085)
Debt assumed	(112,795)		(112,795)
Fair value of retained equity interest	92,120
Equity and/or debt investment held	(54,575)		(54,575)
Other	2,533
Purchase price fair value adjustment	$ 40,078		$ 40,100
388-390 Greenwich Street
Property Acquisitions
Land							$ 516,292
Building and building leasehold							964,434
Contract purchase price		$ 1,585,000					1,584,868
Net consideration funded by us at closing, excluding consideration financed by debt		(208,614)					(208,614)
Debt assumed		(1,162,379)					(1,162,379)
Fair value of retained equity interest		214,007
Equity and/or debt investment held		148,025					(148,025)
Other		5,464
Purchase price fair value adjustment		$ 71,446					71,400
11 Madison Avenue
Property Acquisitions
Land				675,776
Building and building leasehold				1,553,602
Contract purchase price				2,428,359
Net consideration funded by us at closing, excluding consideration financed by debt				0
Debt assumed				0
Equity and/or debt investment held				0
110 Greene Street
Property Acquisitions
Land					$ 45,120
Building and building leasehold					215,470
Contract purchase price					255,000
Net consideration funded by us at closing, excluding consideration financed by debt					0
Debt assumed					0
Equity and/or debt investment held					0
1640 Flatbush Avenue
Property Acquisitions
Land						$ 6,226
Building and building leasehold						501
Contract purchase price						6,800
Net consideration funded by us at closing, excluding consideration financed by debt						0
Debt assumed						0
Equity and/or debt investment held						0
Upper East Side Residential, 11 Madison Avenue, 600 Lexington Ave, 187 Broadway and 5 & 7 Dey Street, 110 Greene Street and 1640 Flatbush Avenue
Property Acquisitions
Operating Leases, Income Statement, Minimum Lease Revenue									7,800
Depreciation and amortization									$ 18,500
As Previously Reported | 183, 187 Broadway & 5-7 Dey Street
Property Acquisitions
Land				22,100
Building and building leasehold				41,000
As Previously Reported | 388-390 Greenwich Street
Property Acquisitions
Land							558,700
Building and building leasehold							$ 1,000,000
As Previously Reported | 11 Madison Avenue
Property Acquisitions
Land				849,900
Building and building leasehold				$ 1,600,000
As Previously Reported | 110 Greene Street
Property Acquisitions
Land					89,300
Building and building leasehold					$ 165,800
As Previously Reported | Upper East Side Residential
Property Acquisitions
Land											$ 17,500
Building and building leasehold											$ 32,500
As Previously Reported | 1640 Flatbush Avenue
Property Acquisitions
Land						6,100
Building and building leasehold						$ 700

Property Acquisitions - Pro For

Property Acquisitions - Pro Forma (Details) - 11 Madison Avenue - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Acquisitions
Actual revenues since acquisition	$ 29,865
Actual net income since acquisition	159
Pro forma revenues	1,657,937	$ 1,540,525
Pro forma income from continuing operations	$ 102,440	$ 376,710
Pro forma basic earnings per share (in usd per share)	$ 0.76	$ 7
Pro forma diluted earnings per share (in usd per share)	$ 0.75	$ 6.92
Mortgage loan
Property Acquisitions
Fixed rate debt	$ 1,400,000	$ 1,400,000
Term (in Years)	10 years	10 years
Interest rate, fixed rate debt (as a percent)	3.838%	3.838%
SL Green Operating Partnership
Property Acquisitions
Pro forma basic earnings per share (in usd per share)	$ 0.76	$ 7
Pro forma diluted earnings per share (in usd per share)	$ 0.75	$ 6.92

Properties Held for Sale and 73

Properties Held for Sale and Property Dispositions - Property Dispositions (Details) $ in Thousands	1 Months Ended													3 Months Ended			12 Months Ended
	Oct. 31, 2016USD ($)	Aug. 31, 2016USD ($)ft²	Jul. 31, 2016USD ($)ft²	Jun. 30, 2016USD ($)ft²	May 31, 2016USD ($)	Feb. 29, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)ft²	Aug. 31, 2015USD ($)ft²	Jan. 31, 2015USD ($)ft²	Nov. 30, 2014USD ($)ft²	Jul. 31, 2014USD ($)ft²	May 31, 2014USD ($)ft²	Jun. 30, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)ft²	Dec. 31, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²																	32,922,082
Gain on Sale																	$ 0	$ 14,122	$ 163,059
Employee compensation award																	2,300
Revenues
Rental revenue																	0	236	51,090
Escalation and reimbursement revenues																	0	(127)	4,646
Other income																	0	0	23
Total revenues																	0	109	55,759
Operating expenses																	0	(631)	7,772
Real estate taxes																	0	250	7,156
Ground rent																	0	0	3,001
Transaction related costs																	0	(49)	89
Interest expense, net of interest income																	0	109	12,652
Amortization of deferred financing costs																	0	3	433
Depreciation and amortization																	0	0	5,581
Total expenses																	0	(318)	36,684
Net income from discontinued operations																	$ 0	$ 427	$ 19,075
400 East 57th Street
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²		290,482
Sales Price		$ 83,300
Gain on Sale		$ 23,900
Employee compensation award	$ 1,000
Ownership percentage in disposed asset	49.00%
11 Madison Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²		2,314,000
Sales Price		$ 2,605,000
Gain on Sale		3,600
Employee compensation award		$ 600
Ownership percentage in disposed asset		40.00%
500 West Putnam Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²			121,500
Sales Price			$ 41,000
Gain on Sale			$ (10,400)
388 Greenwich [Member]
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²				2,635,000										2,635,000
Sales Price				$ 2,002,300
Gain on Sale				206,500
Employee compensation award				$ 1,600
248-252 Bedford Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²						66,611
Sales Price						$ 55,000
Gain on Sale						15,300
Employee compensation award						$ 1,300
885 Third Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²						607,000
Sales Price						$ 453,000
Gain on Sale						$ 0	$ (6,600)
Impairment Charge															$ 6,600
140-150 Grand Street
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²																	215,100
Sales Price							32,000
Gain on Sale							(20,100)
Impairment Charge														$ 10,400		$ 19,200	$ 19,200
570 & 574 Fifth Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²																	24,327
Sales Price							125,400
Gain on Sale							24,600
Employee compensation award							$ 4,000
7 International Drive
Properties Sold [Abstract]
Sales Price					$ 20,000
Gain on Sale					$ (6,900)
120 West 45th Street
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²								440,000								440,000
Sales Price								$ 365,000
Gain on Sale								58,600
Employee compensation award								$ 2,000
131-137 Spring Street
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²									68,342
Sales Price									$ 277,800
Gain on Sale									101,100
Employee compensation award									$ 4,100
Ownership percentage in disposed asset									80.00%
180 Maiden Lane
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²										1,090,000
Sales Price										$ 470,000
Gain on Sale										17,000
Employee compensation award										$ 800
2 Herald Square
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²											354,400
Sales Price											$ 365,000
Gain on Sale											18,800
Employee compensation award											$ 2,500
985-987 Third Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²												13,678
Sales Price												$ 68,700
Gain on Sale												29,800
Employee compensation award												$ 1,300
673 First Avenue
Properties Sold [Abstract]
Approximate Usable Square Feet (sqft) | ft²													422,000
Sales Price													$ 145,000
Gain on Sale													117,600
Employee compensation award													$ 3,400

Debt and Preferred Equity Inv74

Debt and Preferred Equity Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Apr. 30, 2016	Sep. 30, 2014	Jul. 31, 2014
Debt investment
Increase in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 1,015,000	$ 781,000
Decrease in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 1,045,000	520,000
Mortgage Loans on Real Estate, Interest Rate	9.34%
Debt Investments Held [Abstract]
Carrying Value	$ 1,640,412	1,670,020
Mezzanine Loan, with an Initial Maturity Date of June 2017 [Member]
Debt Investments Held [Abstract]
Amount participated out	41,300
Mezzanine Loan, with an Initial Maturity Date of November 2023 [Member]
Debt Investments Held [Abstract]
Amount participated out	5,000
Mezzanine Loan with an Initial Maturity Date of June 2024 [Member]
Debt Investments Held [Abstract]
Amount participated out	12,000
Mezzanine Loan Repaid in April 2016 [Member]
Debt Investments Held [Abstract]
Carrying Value					$ 50,000
Equity Method Investment, Ownership Percentage			20.00%
Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2017 [Member]
Debt Investments Held [Abstract]
Amount participated out	36,300
Mortgage/Mezzanine Loan with an Initial Maturity Date of June 2017 [Member]
Debt Investments Held [Abstract]
Amount participated out	14,500
Mezzanine Loan with an Initial Maturity Date of December 2017 [Member]
Debt Investments Held [Abstract]
Amount participated out	14,600
Mezzanine Loan with an Initial Maturity Date of December 2017, 2 [Member]
Debt Investments Held [Abstract]
Amount participated out	14,100
Mortgage Mezzanine Loan with an Initial Maturity Date of December 2017 [Member]
Debt Investments Held [Abstract]
Amount participated out	5,100
Debt investment
Debt Investments Held [Abstract]
Future Funding Obligations	270,465
Senior Financing	5,219,719
Carrying Value	1,592,537	1,627,844
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	2,264,566
Carrying Value	360,359	511,389
Total fixed rate | Junior Mortgage Participation or Mezzanine Loan with an Initial Maturity Date of March 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,109,000
Carrying Value	193,422	104,661
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of June 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	502,100
Carrying Value	66,129	41,115
Total fixed rate | Mortgage Loan With An Initial Maturity Date Of February 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	26,311	26,262
Loan acquired				$ 26,400
Discount amount				200
Total fixed rate | Mortgage Loan with an Initial Maturity of August 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	380	513
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of September 2021 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000
Carrying Value	3,500	3,500
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of November 2023 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	88,466
Carrying Value	12,692	19,936
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2024 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000
Carrying Value	12,925	24,916
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of January 2025 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000
Carrying Value	30,000	30,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of November 2026 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	340,000
Carrying Value	15,000	0
Total fixed rate | Mezzanine Loan Repaid in July 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	72,102
Total fixed rate | Mezzanine Loan Repaid in April 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	49,691
Total fixed rate | Junior Mortgage Participation Loan Repaid in March 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	49,000
Total fixed rate | Loan Collateralized by Defeasance Securities Repaid in March 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	23,510
Total fixed rate | Loan Collateralized by Defeasance Securities Repaid in March 2016, 2 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	66,183
Total fixed rate | Junior Mortgage Participation, Related To Mortgage Loan, February 2019 [Member]
Debt Investments Held [Abstract]
Loan acquired				5,700
Discount amount				$ 5,700
Total floating rate
Debt Investments Held [Abstract]
Future Funding Obligations	270,465
Senior Financing	2,955,153
Carrying Value	1,232,178	1,116,455
Total floating rate | Mezzanine Loan, with an Initial Maturity Date of June 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000
Carrying Value	15,369	68,977
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	36,042
Senior Financing	0
Carrying Value	145,239	134,264
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	118,949
Carrying Value	29,998	28,551
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of June 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	32,847	0
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of July 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	22,959	22,877
Total floating rate | Mortgage/Mezzanine Loan, September 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	16,960	16,901
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	3,479
Senior Financing	0
Carrying Value	20,423	19,282
Total floating rate | Mezzanine Loan with an Initial Maturity Date of November 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000
Carrying Value	14,957	14,904
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000
Carrying Value	15,141	29,505
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2017, 2 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000
Carrying Value	14,656	28,563
Total floating rate | Mortgage Mezzanine Loan with an Initial Maturity Date of December 2017 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	795
Senior Financing	0
Carrying Value	15,051	14,942
Total floating rate | Junior Mortgage Participation Loan with an Initial Maturity Date of April 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000
Carrying Value	19,913	19,846
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	175,000
Carrying Value	34,844	34,725
Total floating rate | Mortgage/Mezzanine Loan, with an Initial Maturity Date of August 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	523
Senior Financing	20,523
Carrying Value	10,863	31,210
Total floating rate | Mortgage Loan with an Initial Maturity Date of August 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	19,840	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of August 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000
Carrying Value	14,880	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of September 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	37,500
Carrying Value	14,648	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of October 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	2,324
Senior Financing	45,025
Carrying Value	34,502	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of November 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	335,000
Carrying Value	74,476	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	33,000
Carrying Value	26,850	26,777
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018, 2 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	3,317
Senior Financing	165,326
Carrying Value	56,114	52,774
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018, 3 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	15,794
Senior Financing	259,229
Carrying Value	63,137	49,625
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018, 4 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	14,715
Senior Financing	199,935
Carrying Value	64,505	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	45,000
Carrying Value	12,104	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2019, 2 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	6,383
Senior Financing	16,383
Carrying Value	5,410	0
Total floating rate | Mezzanine Loan with an Initial Maturity of March 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000
Carrying Value	21,891	21,845
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	265,000
Carrying Value	24,707	0
Total floating rate | Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	33,573
Senior Financing	183,300
Carrying Value	65,554	0
Total floating rate | Mezzanine Loan, Maturity of September 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	2,500
Senior Financing	187,500
Carrying Value	37,322	0
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of September 2019 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	82,888
Senior Financing	0
Carrying Value	111,819	0
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of January 2020 [Member] [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	35,630
Senior Financing	0
Carrying Value	33,682	0
Total floating rate | Mezzanine Loan with an Initial Maturity of January 2020 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	32,502
Senior Financing	445,483
Carrying Value	125,911	0
Amount participated out	66,100
Total floating rate | Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	30,000
Carrying Value	15,606	0
Total floating rate | Mezzanine Loan Repaid in December 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	49,751
Total floating rate | Mezzanine Loan Repaid in December 2016, 2 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	13,731
Total floating rate | Mezzanine Loan Repaid in November 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	99,530
Total floating rate | Mortgage/Mezzanine Loan Repaid in September 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	94,901
Total floating rate | Jr Mortgage Participation/Mezzanine Loan Repaid in July 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	20,510
Total floating rate | Mezzanine Loan Repaid in June 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	22,625
Total floating rate | Mezzanine Loan Repaid in May 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	74,700
Total floating rate | Mezzanine Loan Contributed for a Joint Venture Interest [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	66,398
Total floating rate | Jr. Mortgage Participation/Mezzanine Loan Repaid in March 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	18,395
Total floating rate | Mezzanine Loan Repaid in February 2016 [Member]
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	$ 0	$ 40,346

Debt and Preferred Equity Inv75

Debt and Preferred Equity Investments (Preferred Equity Investments)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Preferred equity investment
Mortgage Loans on Real Estate, Interest Rate	9.34%
Carrying Value	$ 1,640,412	$ 1,670,020
Preferred Equity with an Initial Mandatory Redemption Date of March 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	71,486
Carrying Value	9,982	9,967
Preferred Equity with an Initial Mandatory Redemption Date of November 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	58,786
Carrying Value	$ 37,893	32,209
Preferred equity investments
Preferred equity investment
Mortgage Loans on Real Estate, Interest Rate	8.16%
Future Funding Obligations	$ 0
Senior Financing	130,272
Carrying Value	$ 47,875	$ 42,176

Debt and Preferred Equity Inv76

Debt and Preferred Equity Investments (Rollforward of Total Allowance for Loan Loss Reserves)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loan loss reserve activity
Balance at beginning of year	$ 0	$ 0	$ 1,000
Expensed	0	0	0
Recoveries	0	0	0
Charge-offs and reclassifications	0	0	(1,000)
Balance at end of year	$ 0	$ 0	$ 0

Debt and Preferred Equity Inv77

Debt and Preferred Equity Investments (Narrative)(Details)	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)segment
Preferred equity investment
Carrying Value	$ 1,640,412,000	$ 1,670,020,000
Number of portfolio segments of financial receivables (segment) | segment	1	1
Additional amount of financing receivables included in other assets	$ 99,500,000	$ 121,500,000
Junior Mortgage Participation Acquired in September 2014
Preferred equity investment
Carrying Value	$ 0

Investments in Unconsolidated78

Investments in Unconsolidated Joint Ventures (Details) $ in Thousands	1 Months Ended				3 Months Ended	12 Months Ended
	Nov. 30, 2016ft²	Oct. 31, 2016	Aug. 31, 2016ft²	Oct. 31, 2015	Mar. 31, 2016	Dec. 31, 2016USD ($)ft²unit	Sep. 30, 2016	Apr. 30, 2016	Dec. 31, 2015USD ($)	Jul. 31, 2014USD ($)
General information on each joint venture
Net equity investment in VIEs in which the entity is not primary beneficiary | $						$ 220,100			$ 39,700
Approximate Square Feet (sqft)						32,922,082
Jericho Plaza
General information on each joint venture
Ownership percentage in disposed asset					66.11%
11 Madison Avenue
General information on each joint venture
Approximate Square Feet (sqft)			2,314,000
Ownership percentage in disposed asset			40.00%
400 East 57th Street
General information on each joint venture
Approximate Square Feet (sqft)			290,482
Ownership percentage in disposed asset		49.00%
100 Park Avenue
General information on each joint venture
Ownership Interest						49.90%
Economic Interest (as a percent)						49.90%
Approximate Square Feet (sqft)						834,000
Acquisition Price | $						$ 95,800
717 Fifth Avenue
General information on each joint venture
Ownership Interest						10.92%
Economic Interest (as a percent)						10.92%
Approximate Square Feet (sqft)						119,500
Acquisition Price | $						$ 251,900
800 Third Avenue
General information on each joint venture
Ownership Interest						60.52%
Economic Interest (as a percent)						60.52%
Approximate Square Feet (sqft)						526,000
Acquisition Price | $						$ 285,000
1745 Broadway
General information on each joint venture
Ownership Interest						56.88%
Economic Interest (as a percent)						56.88%
Approximate Square Feet (sqft)						674,000
Acquisition Price | $						$ 520,000
Jericho Plaza
General information on each joint venture
Ownership Interest						11.67%	20.26%
Economic Interest (as a percent)						11.67%
Approximate Square Feet (sqft)						640,000
Acquisition Price | $						$ 210,000
Ownership interest acquired (percent)				57.52%
11 West 34th Street
General information on each joint venture
Ownership Interest						30.00%
Economic Interest (as a percent)						30.00%
Approximate Square Feet (sqft)						17,150
Acquisition Price | $						$ 10,800
3 Columbus Circle
General information on each joint venture
Ownership Interest						48.90%
Economic Interest (as a percent)						48.90%
Approximate Square Feet (sqft)						741,500
Acquisition Price | $						$ 500,000
280 Park Avenue
General information on each joint venture
Ownership Interest						50.00%
Economic Interest (as a percent)						50.00%
Approximate Square Feet (sqft)						1,219,158
Acquisition Price | $						$ 400,000
1552-1560 Broadway
General information on each joint venture
Ownership Interest						50.00%
Economic Interest (as a percent)						50.00%
Approximate Square Feet (sqft)						35,897
Acquisition Price | $						$ 136,550
724 Fifth Avenue
General information on each joint venture
Ownership Interest						50.00%
Economic Interest (as a percent)						50.00%
Approximate Square Feet (sqft)						65,040
Acquisition Price | $						$ 223,000
10 East 53rd Street
General information on each joint venture
Ownership Interest						55.00%
Economic Interest (as a percent)						55.00%
Approximate Square Feet (sqft)						354,300
Acquisition Price | $						$ 252,500
521 Fifth Avenue
General information on each joint venture
Ownership Interest						50.50%
Economic Interest (as a percent)						50.50%
Approximate Square Feet (sqft)						460,000
Acquisition Price | $						$ 315,000
21 East 66th Street
General information on each joint venture
Ownership Interest						32.28%
Economic Interest (as a percent)						32.28%
Approximate Square Feet (sqft)						16,736
Acquisition Price | $						$ 75,000
650 Fifth Avenue
General information on each joint venture
Ownership Interest						50.00%
Economic Interest (as a percent)						50.00%
Approximate Square Feet (sqft)						69,214
Acquisition Price | $						$ 0
Additional square feet acquired	36,890
Lease term	16 years 10 months
121 Greene Street
General information on each joint venture
Ownership Interest						50.00%
Economic Interest (as a percent)						50.00%
Approximate Square Feet (sqft)						7,131
Acquisition Price | $						$ 27,400
175-225 Third Street Brooklyn, New York
General information on each joint venture
Ownership Interest						95.00%
Economic Interest (as a percent)						95.00%
Approximate Square Feet (sqft)						0
Acquisition Price | $						$ 74,600
55 West 46th Street
General information on each joint venture
Ownership Interest						25.00%
Economic Interest (as a percent)						25.00%
Approximate Square Feet (sqft)						347,000
Acquisition Price | $						$ 295,000
Stonehenge Portfolio
General information on each joint venture
Ownership Interest		90.00%
Approximate Square Feet (sqft)						2,046,733
Acquisition Price | $						$ 36,668
131-137 Spring Street
General information on each joint venture
Ownership Interest						20.00%
Economic Interest (as a percent)						20.00%
Approximate Square Feet (sqft)						68,342
Acquisition Price | $						$ 277,750
76 11th Avenue
General information on each joint venture
Ownership Interest						33.33%
Economic Interest (as a percent)						35.09%
Approximate Square Feet (sqft)						764,000
Acquisition Price | $						$ 138,240
Number of Mezzanine Notes Secured | unit						2
Exit Fee, Percentage Owned						50.00%
Extension Fee, Percentage Owned						38.00%
605 West 42nd Street
General information on each joint venture
Ownership Interest						20.00%
Economic Interest (as a percent)						20.00%
Approximate Square Feet (sqft)						927,358
Acquisition Price | $						$ 759,000
11 Madison Avenue
General information on each joint venture
Ownership Interest						60.00%
Economic Interest (as a percent)						60.00%
Approximate Square Feet (sqft)						2,314,000
Acquisition Price | $						$ 2,605,000
333 East 22nd St
General information on each joint venture
Ownership Interest						33.33%
Economic Interest (as a percent)						33.33%
Approximate Square Feet (sqft)						26,926
Acquisition Price | $						$ 0
400 East 57th Street
General information on each joint venture
Ownership Interest						51.00%
Economic Interest (as a percent)						41.00%
Approximate Square Feet (sqft)						290,482
Acquisition Price | $						$ 170,000
Ownership percentage in disposed asset		49.00%
1552 Broadway
General information on each joint venture
Approximate Square Feet (sqft)						13,045
Joint venture | Stonehenge Portfolio
General information on each joint venture
Ownership Interest		10.00%
Joint venture | Partners' Interest | 76 11th Avenue
General information on each joint venture
Exit Fee, Percentage Owned						25.00%
Extension Fee, Percentage Owned						31.00%
Joint venture | Partners' Interest | 11 Madison Avenue
General information on each joint venture
Equity method investments, depreciation | $						$ 8,400
Mezzanine Loan Repaid in April 2016
General information on each joint venture
Ownership Interest								20.00%
Loans and Leases Receivable, Gross | $										$ 50,000
21 East 66th Street | Three Retail and Two Residential Units
General information on each joint venture
Ownership Interest						32.28%
Number of Stores | unit						3
Number Of Residential Units | unit						2
21 East 66th Street | Three Residential Units
General information on each joint venture
Ownership Interest						16.14%
Number Of Residential Units | unit						3

Investments in Unconsolidated79

Investments in Unconsolidated Joint Ventures Investments in Unconsolidated Joint Ventures (Acquisition, Development and Construction Arrangements/Sale of Joint Venture Interest or Property)(Details) $ in Thousands

1 Months Ended

12 Months Ended

Sep. 30, 2016USD ($)

May 31, 2016USD ($)

Mar. 31, 2016USD ($)

Feb. 29, 2016USD ($)

Sep. 30, 2015USD ($)

Aug. 31, 2015USD ($)

Sep. 30, 2014USD ($)

May 31, 2014USD ($)unit

Mar. 31, 2014USD ($)

Jan. 31, 2014USD ($)ft²

Dec. 31, 2016USD ($)ft²

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Schedule of Equity Method Investments [Line Items]

Acquisition, development and construction arrangements, carrying value

$ 170,164

$ 145,878

Gain (Loss) on Sale

0

14,122

$ 163,059

Employee compensation award

$ 2,300

Approximate Square Feet (sqft) | ft²

32,922,082

West Coast Office portfolio

Schedule of Equity Method Investments [Line Items]

Number of apartment units | unit

1

Participating Financing Due March 2017

Schedule of Equity Method Investments [Line Items]

Acquisition, development and construction arrangements, carrying value

$ 100,000

99,936

Participating Financing Due February 2022

Schedule of Equity Method Investments [Line Items]

Acquisition, development and construction arrangements, carrying value

45,622

45,942

Mezzanine Loan Due July 2036

Schedule of Equity Method Investments [Line Items]

Acquisition, development and construction arrangements, carrying value

$ 24,542

$ 0

EOP Denver

Schedule of Equity Method Investments [Line Items]

Ownership Interest

0.48%

Gross Asset Valuation

$ 180,700

Gain (Loss) on Sale

$ 300

33 Beekman

Schedule of Equity Method Investments [Line Items]

Ownership Interest

45.90%

Gross Asset Valuation

$ 196,000

Gain (Loss) on Sale

33,000

Promote recognized

$ 10,800

EOP Denver

Schedule of Equity Method Investments [Line Items]

Ownership Interest

4.79%

Gross Asset Valuation

$ 180,700

Gain (Loss) on Sale

$ 2,800

7 Renaissance

Schedule of Equity Method Investments [Line Items]

Ownership Interest

50.00%

Gross Asset Valuation

$ 20,700

Gain (Loss) on Sale

$ 4,200

1 Jericho

Schedule of Equity Method Investments [Line Items]

Ownership Interest

66.11%

11.67%

77.78%

Gross Asset Valuation

$ 95,200

Gain (Loss) on Sale

$ 3,300

The Meadows

Schedule of Equity Method Investments [Line Items]

Ownership Interest

50.00%

Gross Asset Valuation

$ 121,100

Gain (Loss) on Sale

$ (1,600)

315 West 36th Street

Schedule of Equity Method Investments [Line Items]

Ownership Interest

35.50%

Gross Asset Valuation

$ 115,000

Gain (Loss) on Sale

$ 16,300

180 Broadway

Schedule of Equity Method Investments [Line Items]

Ownership Interest

25.50%

Gross Asset Valuation

$ 222,500

Gain (Loss) on Sale

16,500

Promote recognized

$ 3,300

747 Madison Avenue

Schedule of Equity Method Investments [Line Items]

Ownership Interest

33.33%

Gross Asset Valuation

$ 160,000

Gain (Loss) on Sale

0

Promote recognized

10,300

Preferred equity investment

30,000

Deferred gain on sale

$ 13,100

West Coast Office portfolio

Schedule of Equity Method Investments [Line Items]

Ownership Interest

42.02%

Gross Asset Valuation

$ 756,000

Gain (Loss) on Sale

$ 85,600

Number of apartment units | unit

5

21-25 West 34th Street

Schedule of Equity Method Investments [Line Items]

Ownership Interest

49.90%

Gross Asset Valuation

$ 114,900

Gain (Loss) on Sale

$ 20,900

Approximate Square Feet (sqft) | ft²

91,300

Joint venture | 747 Madison Avenue | 30 East 65th Street

Schedule of Equity Method Investments [Line Items]

Investment's ownership percentage in joint venture

100.00%

Investments in Unconsolidated80

Investments in Unconsolidated Joint Ventures (Mortgages and Other Loans Payable)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Feb. 28, 2017	Jan. 31, 2017	Oct. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total fixed rate debt	$ 3,518,127				$ 5,816,010
Total floating rate debt	622,585				1,205,494
Total fixed rate and floating rate debt	4,140,712				7,021,504
Deferred financing costs, net	$ (82,300)				(130,300)
1745 Broadway
Debt Instrument [Line Items]
Ownership Interest	56.88%
521 Fifth Avenue
Debt Instrument [Line Items]
Ownership Interest	50.50%
717 Fifth Avenue
Debt Instrument [Line Items]
Ownership Interest	10.92%
21 East 66th Street
Debt Instrument [Line Items]
Ownership Interest	32.28%
3 Columbus Circle
Debt Instrument [Line Items]
Ownership Interest	48.90%
11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	$ 0				1,400,000
Ownership Interest	60.00%
800 Third Avenue
Debt Instrument [Line Items]
Ownership Interest	60.52%
400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt	$ 0				67,644
Ownership Interest	51.00%
Stonehenge Portfolio
Debt Instrument [Line Items]
Ownership Interest				90.00%
280 Park Avenue
Debt Instrument [Line Items]
Ownership Interest	50.00%
10 East 53rd Street
Debt Instrument [Line Items]
Ownership Interest	55.00%
724 Fifth Avenue
Debt Instrument [Line Items]
Ownership Interest	50.00%
55 West 46th Street
Debt Instrument [Line Items]
Ownership Interest	25.00%
175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Ownership Interest	95.00%
605 West 42nd Street
Debt Instrument [Line Items]
Ownership Interest	20.00%
650 Fifth Avenue
Debt Instrument [Line Items]
Ownership Interest	50.00%
121 Greene Street
Debt Instrument [Line Items]
Ownership Interest	50.00%
131-137 Spring Street
Debt Instrument [Line Items]
Ownership Interest	20.00%
11 West 34th Street
Debt Instrument [Line Items]
Ownership Interest	30.00%
100 Park Avenue
Debt Instrument [Line Items]
Ownership Interest	49.90%
Joint venture
Debt Instrument [Line Items]
Total fixed rate debt	$ 3,566,846				2,645,131
Total floating rate debt	2,982,528				1,663,982
Total fixed rate and floating rate debt	6,549,374				4,309,113
Deferred financing costs, net	(95,408)				(42,565)
Total joint venture mortgages and other loans payable, net	6,453,966				4,266,548
Joint venture | 1745 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	340,000				340,000
Joint venture | 521 Fifth Avenue
Debt Instrument [Line Items]
Total fixed rate debt	170,000				170,000
Joint venture | 717 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Committed amount	300,000
Joint venture | 717 Fifth Avenue | Mezzanine loans
Debt Instrument [Line Items]
Committed amount	355,300
Joint venture | 717 Fifth Avenue | Secured Debt, Initial Maturity July 2022 [Member]
Debt Instrument [Line Items]
Total fixed rate debt	300,000				300,000
Joint venture | 717 Fifth Avenue | Secured Debt, Initial Maturity July 2022, 2 [Member]
Debt Instrument [Line Items]
Total fixed rate debt	355,328				325,704
Joint venture | 21 East 66th Street
Debt Instrument [Line Items]
Total fixed rate debt	12,000				12,000
Total floating rate debt	1,726				1,805
Joint venture | 3 Columbus Circle
Debt Instrument [Line Items]
Total fixed rate debt	350,000				350,000
Joint venture | 11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	1,400,000				0
Joint venture | 800 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt	177,000				20,910
Joint venture | 400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt	100,000				0
Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Total fixed rate debt	362,518				430,627
Total floating rate debt	65,577				10,500
Ownership Interest				10.00%
Joint venture | Stonehenge Portfolio | Initial Maturity April 2017
Debt Instrument [Line Items]
Total fixed rate debt	13,100
Joint venture | Stonehenge Portfolio | Initial Maturity November 2017
Debt Instrument [Line Items]
Total fixed rate debt	34,500
Joint venture | Stonehenge Portfolio | Initial Maturity August 2019
Debt Instrument [Line Items]
Total fixed rate debt	139,700
Joint venture | Stonehenge Portfolio | Initial Maturity June 2024
Debt Instrument [Line Items]
Total fixed rate debt	175,200
Joint venture | Stonehenge Portfolio | Floating-Rate Mortgage Maturing in June 2017
Debt Instrument [Line Items]
Total floating rate debt	55,300
Joint venture | Stonehenge Portfolio | Floating-Rate Mortgage Maturing in December 2017
Debt Instrument [Line Items]
Total floating rate debt	10,200
Joint venture | 280 Park Avenue
Debt Instrument [Line Items]
Total fixed rate debt	0				692,963
Total floating rate debt	900,000				30,000
Joint venture | 7 Renaissance
Debt Instrument [Line Items]
Total fixed rate debt	0				2,927
Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Total floating rate debt	125,000				125,000
Joint venture | 724 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt	275,000				275,000
Joint venture | 1552 Broadway
Debt Instrument [Line Items]
Total floating rate debt	185,410				190,409
Joint venture | 1552 Broadway | Mortgage loan
Debt Instrument [Line Items]
Committed amount	145,000
Unfunded amount	600
Joint venture | 1552 Broadway | Mezzanine loans
Debt Instrument [Line Items]
Committed amount	41,500
Unfunded amount	500
Joint venture | 55 West 46th Street
Debt Instrument [Line Items]
Total floating rate debt	157,322				150,000
Joint venture | 55 West 46th Street | Mortgage loan
Debt Instrument [Line Items]
Committed amount	190,000
Unfunded amount	32,700
Joint venture | 175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Total floating rate debt	40,000				40,000
Joint venture | Jericho Plaza
Debt Instrument [Line Items]
Total floating rate debt	$ 76,993				163,750
Ownership Interest	11.67%
Term (in Years)	2 years
Face amount of loan	$ 100,000
Joint venture | 605 West 42nd Street
Debt Instrument [Line Items]
Total floating rate debt	539,000				0
Joint venture | 650 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt	77,500				65,000
Joint venture | 650 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Committed amount	97,000
Unfunded amount	19,500
Joint venture | 121 Greene Street
Debt Instrument [Line Items]
Total floating rate debt	15,000				15,000
Joint venture | 131-137 Spring Street
Debt Instrument [Line Items]
Total floating rate debt	141,000				141,000
Joint venture | 11 West 34th Street
Debt Instrument [Line Items]
Total floating rate debt	23,000				23,000
Joint venture | 100 Park Avenue
Debt Instrument [Line Items]
Total floating rate debt	360,000				360,000
Joint venture | 33 Beekman
Debt Instrument [Line Items]
Total floating rate debt	$ 0				$ 73,518
Weighted Average | Joint venture | 1745 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.68%
Weighted Average | Joint venture | 521 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.73%
Weighted Average | Joint venture | 717 Fifth Avenue | Secured Debt, Initial Maturity July 2022 [Member]
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.45%
Weighted Average | Joint venture | 717 Fifth Avenue | Secured Debt, Initial Maturity July 2022, 2 [Member]
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	6.52%
Weighted Average | Joint venture | 21 East 66th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.60%
Interest rate, floating rate debt (as a percent)	3.00%
Weighted Average | Joint venture | 3 Columbus Circle
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.61%
Weighted Average | Joint venture | 11 Madison Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.84%
Weighted Average | Joint venture | 800 Third Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.24%
Weighted Average | Joint venture | 400 East 57th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.00%
Weighted Average | Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.19%
Interest rate, floating rate debt (as a percent)	5.71%
Weighted Average | Joint venture | 280 Park Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.51%
Weighted Average | Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.98%
Weighted Average | Joint venture | 724 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.90%
Weighted Average | Joint venture | 1552 Broadway
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.68%
Weighted Average | Joint venture | 55 West 46th Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.78%
Weighted Average | Joint venture | 175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.51%
Weighted Average | Joint venture | Jericho Plaza
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.64%
Weighted Average | Joint venture | 605 West 42nd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.91%
Weighted Average | Joint venture | 650 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.10%
Weighted Average | Joint venture | 121 Greene Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.98%
Weighted Average | Joint venture | 131-137 Spring Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.03%
Weighted Average | Joint venture | 11 West 34th Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.93%
Weighted Average | Joint venture | 100 Park Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.23%
Subsequent Event | Joint venture | 1745 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)			1.85%
Total fixed rate debt			$ 375,000
Subsequent Event | Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Total floating rate debt		$ 170,000
LIBOR | Subsequent Event | Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.25%

Investments in Unconsolidated81

Investments in Unconsolidated Joint Ventures (Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures)(Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Commercial real estate property, net	$ 10,478,638				$ 14,620,896				$ 10,478,638	$ 14,620,896
Cash and cash equivalents	279,443				255,399				279,443	255,399	$ 281,409	$ 206,692
Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance	53,772				63,491				53,772	63,491
Other assets	614,067				850,939				614,067	850,939
Liabilities and members' equity
Mortgages and other loans payable, net	4,073,830				6,881,920				4,073,830	6,881,920
Deferred revenue	217,955				399,102				217,955	399,102
Other liabilities	206,238				168,477				206,238	168,477
Company's investments in unconsolidated joint ventures	1,890,186				1,203,858				1,890,186	1,203,858
Combined statements of income for the unconsolidated joint ventures
Operating expenses									312,859	301,624	282,283
Ground rent									33,261	32,834	32,307
Real estate taxes									248,388	232,702	217,843
Interest expense, net of interest income									321,199	323,870	317,400
Amortization of deferred financing costs									24,564	27,348	22,377
Transaction related costs									7,528	11,430	8,707
Depreciation and amortization									821,041	560,887	371,610
Total expenses									1,868,599	1,585,568	1,345,015
Company's equity in net income from unconsolidated joint ventures	(95)	$ (3,968)	$ 5,841	$ 10,096	2,377	$ 3,627	$ 2,994	$ 4,030	11,874	13,028	26,537
Joint venture
Investment in Unconsolidated Joint Ventures
Management fees, base revenue									8,100	6,900	16,900
Assets
Commercial real estate property, net	9,131,717				6,122,468				9,131,717	6,122,468
Cash and cash equivalents	328,455				258,564				328,455	258,564
Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance	232,778				208,802				232,778	208,802
Debt and preferred equity investments, net	336,164				145,878				336,164	145,878
Other assets	683,481				248,474				683,481	248,474
Total assets	10,712,595				6,984,186				10,712,595	6,984,186
Liabilities and members' equity
Mortgages and other loans payable, net	6,453,966				4,266,548				6,453,966	4,266,548
Deferred revenue	356,414				209,095				356,414	209,095
Other liabilities	391,500				314,065				391,500	314,065
Members' equity	3,510,715				2,194,478				3,510,715	2,194,478
Total liabilities and members' equity	$ 10,712,595				$ 6,984,186				10,712,595	6,984,186
Combined statements of income for the unconsolidated joint ventures
Total revenues									712,689	576,845	522,132
Operating expenses									126,913	106,613	82,436
Ground rent									14,924	14,083	9,898
Real estate taxes									111,673	89,734	64,217
Interest expense, net of interest income									197,741	199,126	178,743
Amortization of deferred financing costs									24,829	13,394	12,395
Transaction related costs									5,566	615	535
Depreciation and amortization									199,011	149,023	137,793
Total expenses									680,657	572,588	486,017
Loss on early extinguishment of debt									(1,606)	(1,089)	(6,743)
Net income before gain on sale									30,426	3,168	29,372
Company's equity in net income from unconsolidated joint ventures									$ 11,874	$ 13,028	$ 26,537

Deferred Costs (Details)

Deferred Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs	$ 468,971
Less: accumulated amortization	(201,371)
Deferred costs, net	$ 267,600	$ 239,920

Mortgages and Other Loans Pay83

Mortgages and Other Loans Payable (Details)	Dec. 06, 2015USD ($)	Oct. 31, 2016	Aug. 31, 2016	Dec. 31, 2016USD ($)extenstion_option$ / shares	Dec. 31, 2016USD ($)$ / shares	Jan. 31, 2017USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Total fixed rate debt				$ 3,518,127,000	$ 3,518,127,000			$ 5,816,010,000
Total floating rate debt				622,585,000	622,585,000			1,205,494,000
Total fixed rate and floating rate debt				4,140,712,000	4,140,712,000			7,021,504,000
Mortgages reclassed to liabilities related to assets held for sale (15)				0	0			(29,000,000)
Total mortgages and other loans payable				4,140,712,000	4,140,712,000			6,992,504,000
Deferred financing costs, net of amortization				(66,882,000)	(66,882,000)			(110,584,000)
Total mortgages and other loans payable				4,073,830,000	4,073,830,000			6,881,920,000
Debt Issuance Costs, Net				82,300,000	82,300,000			130,300,000
Federal Home Loan Bank Advances outstanding				$ 205,000,000	$ 205,000,000
Federal Home Loan Bank, advances, weighted-average borrowing rate (as a percent)				0.92%	0.92%
Book value of collateral				$ 6,000,000,000	$ 6,000,000,000			10,800,000,000
Series J Preferred Units
Debt Instrument [Line Items]
Total fixed rate debt				4,000,000	4,000,000			4,000,000
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest				$ 4,000,000	$ 4,000,000
Preferred Units (as a percent)					3.75%
Preferred Units, liquidation preference (in dollars per unit) | $ / shares				$ 1,000	$ 1,000
Series J Preferred Units | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.75%	3.75%
FHLB Advance Maturing in January 2017 [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 105,000,000	$ 105,000,000			0
FHLB Advance Maturing in January 2017 [Member] | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				1.03%	1.03%
FHLB Advance Maturing in January 2017, 2 [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 100,000,000	$ 100,000,000			0
FHLB Advance Maturing in January 2017, 2 [Member] | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				0.80%	0.80%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 16,000,000	$ 16,000,000			16,000,000
Unsecured Debt [Member] | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				4.81%	4.81%
Master Repurchase Agreement
Debt Instrument [Line Items]
Total floating rate debt				$ 184,642,000	$ 184,642,000			253,424,000
Maximum facility capacity				$ 300,000,000	$ 300,000,000
Basis Point Fee (as a percent)	0.25%
Threshold amount for basis point fee to be applicable (less than)	$ 150,000,000
Master Repurchase Agreement | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.04%	3.04%
Master Repurchase Agreement | Minimum | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					2.25%
Master Repurchase Agreement | Maximum | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					4.00%
FHLB Advance Maturing in December 2016
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			45,750,000
485 Lexington Avenue (3)
Debt Instrument [Line Items]
Total fixed rate debt				$ 450,000,000	$ 450,000,000			450,000,000
485 Lexington Avenue (3) | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.61%	5.61%
762 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 7,694,000	$ 7,694,000			7,872,000
762 Madison Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.86%	3.86%
One Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 517,806,000	$ 517,806,000			542,817,000
One Madison Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.91%	5.91%
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 221,446,000	$ 221,446,000			225,099,000
100 Church Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				4.68%	4.68%
919 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 500,000,000	$ 500,000,000			500,000,000
Interest in property (as a percent)				51.00%	51.00%
919 Third Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.12%	5.12%
420 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 300,000,000	$ 300,000,000			300,000,000
420 Lexington Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.99%	3.99%
1515 Broadway
Debt Instrument [Line Items]
Total fixed rate debt				$ 888,531,000	$ 888,531,000			900,000,000
1515 Broadway | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.93%	3.93%
400 East 58th Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 40,000,000	$ 40,000,000			28,990,000
400 East 58th Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.00%	3.00%
Term (in Years)					5 years
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt				$ 100,000,000	$ 100,000,000			79,562,000
Landmark Square | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.05%	5.05%
885 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 267,650,000	$ 267,650,000			267,650,000
885 Third Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				6.26%	6.26%
400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 0	$ 0			67,644,000
Ownership percentage in disposed asset		49.00%
11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				0	0			1,400,000,000
388-390 Greenwich Street
Debt Instrument [Line Items]
Total fixed rate debt				0	0			1,004,000,000
Total floating rate debt				0	0			446,000,000
500 West Putnam Avenue
Debt Instrument [Line Items]
Total fixed rate debt				0	0			22,376,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 37,388,000	$ 37,388,000			0
719 Seventh Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.55%	3.55%
183, 187 Broadway & 5-7 Dey Street
Debt Instrument [Line Items]
Total floating rate debt				$ 58,000,000	$ 58,000,000			40,000,000
183, 187 Broadway & 5-7 Dey Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.16%	3.16%
1080 Amsterdam (13)
Debt Instrument [Line Items]
Total floating rate debt				$ 3,525,000	$ 3,525,000			3,525,000
1080 Amsterdam (13) | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				4.23%	4.23%
220 East 42nd Street
Debt Instrument [Line Items]
Total floating rate debt				$ 275,000,000	$ 275,000,000			275,000,000
220 East 42nd Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				2.08%	2.08%
One Vanderbilt
Debt Instrument [Line Items]
Total floating rate debt				$ 64,030,000	$ 64,030,000			0
One Vanderbilt | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				4.09%	4.09%
One Vanderbilt | Construction Loans [Member]
Debt Instrument [Line Items]
Term (in Years)					5 years
Maximum facility capacity							$ 1,500,000,000
Debt Instrument, Number of Extension Options | extenstion_option				2
Debt Instrument, Period of Extension Option					1 year
One Vanderbilt | Construction Loans [Member] | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					3.50%
600 Lexington Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			112,795,000
248-252 Bedford Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			29,000,000
Debt Issuance Costs, Net								$ 600,000
11 Madison Avenue
Debt Instrument [Line Items]
Ownership percentage in disposed asset			40.00%
Subsequent Event | 485 Lexington Avenue (3)
Debt Instrument [Line Items]
Total fixed rate debt						$ 450,000,000
Subsequent Event | 485 Lexington Avenue (3) | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)						4.22%
Subsequent Event | 1080 Amsterdam (13)
Debt Instrument [Line Items]
Total floating rate debt						$ 47,000,000

Corporate Indebtedness (Details

Corporate Indebtedness (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Corporate Indebtedness
Outstanding under line of credit facility	$ 0	$ 985,055,000
Long-term Debt	6,568,712,000
Revolving credit facility
Corporate Indebtedness
Credit facility, maximum borrowing capacity	1,600,000,000
Maximum borrowing capacity, optional expansion	$ 3,000,000,000
Effective rate (as a percent)	1.78%
Facility fee (as a percent)	0.25%
Outstanding under line of credit facility	$ 0
Revolving credit facility | Minimum
Corporate Indebtedness
Facility fee (as a percent)	0.125%
Revolving credit facility | Maximum
Corporate Indebtedness
Facility fee (as a percent)	0.30%
Revolving credit facility | LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.25%
Revolving credit facility | LIBOR | Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.875%
Revolving credit facility | LIBOR | Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.55%
Term loan
Corporate Indebtedness
Credit facility, maximum borrowing capacity	$ 1,183,000,000
Effective rate (as a percent)	2.27%
Long-term Debt	$ 1,183,000,000
Term loan | LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.40%
Term loan | LIBOR | Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.95%
Term loan | LIBOR | Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.90%
2012 Credit Facility
Corporate Indebtedness
Letters of credit	$ 56,500,000
Ability to borrow under line of credit facility	1,500,000,000
Long-term Debt	0
Line of Credit [Member] | Term loan
Corporate Indebtedness
Long-term Debt	1,200,000,000	929,500,000
Line of Credit [Member] | 2012 Credit Facility
Corporate Indebtedness
Long-term Debt	$ (6,300,000)	$ 985,100,000

Corporate Indebtedness (Senior

Corporate Indebtedness (Senior Unsecured Notes)(Details)	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Oct. 06, 2010USD ($)$ / shares
Debt disclosures by scheduled maturity date
Deferred financing costs, net	$ (82,300,000)	$ (130,300,000)
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	1,145,000,000
Accreted Balance	1,133,957,000	1,386,244,000
Deferred financing costs, net	(5,642,000)	(7,280,000)
Senior Notes, Net of Deferred Finance Costs	1,128,315,000	1,378,964,000
Senior unsecured notes | 3.00% Senior unsecured notes maturing on October 15, 2017
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	345,000,000
Accreted Balance	$ 334,077,000	321,130,000
Coupon Rate (as a percent)	3.00%
Effective rate (as a percent)	3.00%
Term (in Years)	7 years
Premium on sale price to calculate exchange price of notes (as a percent)			30.00%
Exchange price (in dollars per share) | $ / shares			$ 85.81
Adjusted exchange rate for the debentures (in shares)	12.6478
Principal amount of debentures, basis for conversion	$ 1,000
Amount of convertible debt recorded in equity			$ 78,300,000
Debt Instrument, Unamortized Discount	10,900,000
Senior unsecured notes | 5.00% Senior unsecured notes maturing on August 15, 2018
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	250,000,000
Accreted Balance	$ 249,880,000	249,810,000
Coupon Rate (as a percent)	5.00%
Effective rate (as a percent)	5.00%
Term (in Years)	7 years
Senior unsecured notes | 7.75% Senior unsecured notes maturing on March 15, 2020
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 250,000,000
Accreted Balance	$ 250,000,000	250,000,000
Coupon Rate (as a percent)	7.75%
Effective rate (as a percent)	7.75%
Term (in Years)	10 years
Senior unsecured notes | 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 200,000,000
Accreted Balance	$ 200,000,000	200,000,000
Coupon Rate (as a percent)	4.50%
Effective rate (as a percent)	4.50%
Term (in Years)	10 years
Senior unsecured notes | 4.27% Senior unsecured notes maturing on December 17, 2025
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 100,000,000
Accreted Balance	$ 100,000,000	100,000,000
Coupon Rate (as a percent)	4.27%
Effective rate (as a percent)	4.27%
Term (in Years)	10 years
Senior unsecured notes | 3.00% Senior unsecured notes maturing on March 30, 2027
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 0
Accreted Balance	0	10,008,000
Senior unsecured notes | 6.00% Senior unsecured notes maturing on March 31, 2016
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	0
Accreted Balance	$ 0	$ 255,296,000

Corporate Indebtedness (Junior

Corporate Indebtedness (Junior Subordinated Deferrable Interest Debentures and Principal Maturities)(Details) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2005	Dec. 31, 2016
Scheduled Amortization and Principal Repayments
2,017		$ 1,326,860,000
2,018		603,926,000
2,019		1,241,916,000
2,020		970,231,000
2,021		93,696,000
Thereafter		2,332,083,000
Total amortization of debt and principal repayments		6,568,712,000
Joint Venture Debt
Principal Repayments and Joint Venture Debt
2,017		574,327,000
2,018		48,253,000
2,019		555,545,000
2,020		31,183,000
2,021		222,452,000
Thereafter		1,311,022,000
Total principal repayments		$ 2,742,782,000
Trust Preferred Securities
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	$ 100,000,000
Coupon Rate (as a percent)		5.61%
Number of Years from Issuance of Debt for which Fixed Rate of Interest will be in Force		10 years
Scheduled Amortization and Principal Repayments
2,017		$ 0
2,018		0
2,019		0
2,020		0
2,021		0
Thereafter		100,000,000
Total amortization of debt and principal repayments		$ 100,000,000
Trust Preferred Securities | LIBOR
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		1.25%
Mortgages and other loans payable
Scheduled Amortization
2,017		$ 51,531,000
2,018		54,371,000
2,019		58,916,000
2,020		40,700,000
2,021		29,666,000
Thereafter		86,275,000
Total amortization of debt		321,459,000
Principal Repayments and Joint Venture Debt
2,017		930,329,000
2,018		299,555,000
2,019		0
2,020		679,531,000
2,021		64,030,000
Thereafter		1,845,808,000
Total principal repayments		3,819,253,000
Revolving Credit Facility
Scheduled Amortization and Principal Repayments
2,017		0
2,018		0
2,019		0
2,020		0
2,021		0
Thereafter		0
Total amortization of debt and principal repayments		0
Unsecured Term Loan
Scheduled Amortization and Principal Repayments
2,017		0
2,018		0
2,019		1,183,000,000
2,020		0
2,021		0
Thereafter		0
Total amortization of debt and principal repayments		$ 1,183,000,000
Unsecured Term Loan | LIBOR
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		1.40%
Senior Unsecured Notes
Scheduled Amortization and Principal Repayments
2,017		$ 345,000,000
2,018		250,000,000
2,019		0
2,020		250,000,000
2,021		0
Thereafter		300,000,000
Total amortization of debt and principal repayments		$ 1,145,000,000

Corporate Indebtedness (Schedul

Corporate Indebtedness (Schedule of Consolidated Interest Expense, Excluding Capitalized Interest)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest expense
Interest expense before capitalized interest	$ 348,062	$ 357,926	$ 342,648
Interest capitalized	(24,067)	(31,108)	(22,750)
Interest income	(2,796)	(2,948)	(2,498)
Interest expense, net	$ 321,199	$ 323,870	$ 317,400

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amounts due from/to related parties
Due from joint ventures	$ 1,240	$ 1,334
Other	14,616	9,316
Related party receivables	15,856	10,650
Alliance Building Services
Related Party Transactions
Profit participation from related party	3,500	3,800	$ 3,800
Payments made for services	23,400	21,300	21,500
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party	$ 700	$ 500	$ 400

Noncontrolling Interests on t89

Noncontrolling Interests on the Company's Consolidated Financial Statements (Details)	1 Months Ended	12 Months Ended
	Jan. 31, 2012$ / sharesshares	Dec. 31, 2016USD ($)shares$ / shares	Dec. 31, 2015USD ($)unit$ / sharesshares	Dec. 31, 2014USD ($)shares	Mar. 31, 2016shares	Aug. 31, 2015shares	Jul. 31, 2015shares	Jun. 30, 2015shares	Feb. 28, 2015shares	Aug. 31, 2014shares
Organization
Basic weighted average common shares outstanding (in shares) | shares		100,185,000	99,345,000	95,774,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $		$ 424,206,000
Distributions | $		(15,419,000)	$ (119,784,000)	$ (7,019,000)
Redemption of common units | $			(20,650,000)
Net income | $		10,136,000	10,565,000	18,467,000
Accumulated other comprehensive income allocation | $		1,299,000	(67,000)	$ 175,000
Balance at end of period | $		$ 473,882,000	$ 424,206,000
Number of company common stock issued on conversion of Series B preferred units		6.71348
SL Green Operating Partnership
Organization
Basic weighted average common shares outstanding (in shares) | shares		104,508,000	103,244,000	99,288,000
Noncontrolling interest in the operating partnership (as a percent)		4.16%
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $		$ 424,206,000	$ 469,524,000
Distributions | $		(12,671,000)	(9,710,000)
Issuance of common units | $		78,495,000	30,506,000
Redemption of common units | $		(31,805,000)	(55,697,000)
Net income | $		10,136,000	10,565,000
Accumulated other comprehensive income allocation | $		1,299,000	(67,000)
Fair value adjustment | $		4,222,000	(20,915,000)
Balance at end of period | $		$ 473,882,000	$ 424,206,000	$ 469,524,000
Stock-based compensation plans (shares) | shares		373,000	490,000	408,000
SL Green Operating Partnership | Series G Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares	1,902,000
Dividend rate preferred units (as a percent)	4.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 1.125
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares		$ 88.50
Number of company common stock issue on redemption of operation partnership common units		1
SL Green Operating Partnership | Series F Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares		60
Mandatory liquidation preference (in dollars per share) | $		$ 1,000
SL Green Operating Partnership | Series K Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares										563,954
Dividend rate preferred units (as a percent)		3.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares		$ 134.67
Preferred Units, shares authorized | shares		700,000
SL Green Operating Partnership | Series L Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares										378,634
Dividend rate preferred units (as a percent)		4.00%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 1
Preferred Units, shares authorized | shares		500,000
SL Green Operating Partnership | Series M Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares									1,600,000
Dividend rate preferred units (as a percent)		3.75%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 0.9375
Preferred Units, shares authorized | shares		1,600,000
SL Green Operating Partnership | Series N Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares								552,303
Dividend rate preferred units (as a percent)		3.00%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 0.75
Preferred Units, shares authorized | shares		552,303
SL Green Operating Partnership | Series O Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)		6.25%
Preferred Units, shares authorized | shares		1
SL Green Operating Partnership | Series P Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		200,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares							200,000
Dividend rate preferred units (as a percent)		4.00%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 1
SL Green Operating Partnership | Series Q Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		268,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares							268,000
Dividend rate preferred units (as a percent)		3.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares		$ 148.95
SL Green Operating Partnership | Series R Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		400,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares						400,000
Dividend rate preferred units (as a percent)		3.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares		$ 154.89
SL Green Operating Partnership | Series S Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		1,077,280
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares						1,077,280
Dividend rate preferred units (as a percent)		4.00%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 1
SL Green Operating Partnership | Series T Preferred Stock [Member] [Member]
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		230,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares					230,000
Dividend rate preferred units (as a percent)		2.75%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		0.6875
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares		$ 119.02
SL Green Operating Partnership | Series U Preferred Stock [Member]
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		680,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares					680,000
Dividend rate preferred units (as a percent)		4.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 1.125
SL Green Operating Partnership | Series A Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		109,161
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares						109,161
Dividend rate preferred units (as a percent)		3.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 1,000
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 35
SL Green Operating Partnership | Series B Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares		0
SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)			3.61%
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)		4,363,716	3,745,766
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		4,363,716
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Distributions | $		$ (15,419,000)	$ (119,784,000)	$ (7,019,000)
Redemption of common units | $			(20,650,000)
Accumulated other comprehensive income allocation | $		$ 1,299,000	$ (67,000)	$ 175,000
Number of preferred units issued (in shares) | shares		9,200,000	9,200,000
Liquidation preference of preferred units (in dollars per share) | $ / shares		$ 25	$ 25
Minimum | SL Green Operating Partnership | Series U Preferred Stock [Member]
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Annual dividends on preferred units (in dollars per share) | $ / shares		$ 0.75

Noncontrolling Interests on t90

Noncontrolling Interests on the Company's Consolidated Financial Statements - Preferred Unit Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Rollforward Analysis of Preferred Unit Activity
Redemption of preferred units		$ (20,650)
SL Green Operating Partnership
Rollforward Analysis of Preferred Unit Activity
Issuance of preferred units	$ 78,495	30,506
Redemption of preferred units	(31,805)	(55,697)
SL Green Operating Partnership | Preferred Units
Rollforward Analysis of Preferred Unit Activity
Balance at beginning of period	282,516	71,115
Issuance of preferred units	22,793	211,601
Redemption of preferred units	(3,299)	(200)
Balance at end of period	$ 302,010	$ 282,516

Stockholders' Equity of the C91

Stockholders' Equity of the Company (Details) - $ / shares	Dec. 31, 2016	Aug. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Authorized capital stock (shares)	260,000,000
Authorized shares, par value (in dollars per share)	$ 0.01
Common stock, shares authorized	160,000,000		160,000,000
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Excess stock, shares authorized (shares)	75,000,000
Excess stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares authorized (shares)	25,000,000
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Excess shares issued (shares)	0
Stock repurchase program, number of shares authorized to be repurchased		1,000,000,000

Stockholders' Equity of the C92

Stockholders' Equity of the Company (At-the-Market Equity Offering Program and Perpetual Preferred Stock)(Details) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2012	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Jul. 31, 2011
Stockholders' Equity
Contributions - net proceeds from common stock offering (in shares)					1,626,999
Proceeds from sale of common stock			$ 0	$ 124,761,000	$ 185,321,000
Preferred stock, shares outstanding			9,200,000	9,200,000
Perpetual Preferred stock, liquidation preference (in dollars per share)			$ 25	$ 25
At-the-Market Equity Offering Programs
Stockholders' Equity
Aggregate value of the shares of common stock to be sold							$ 250,000,000
Contributions - net proceeds from common stock offering (in shares)				25,659
Proceeds from sale of common stock		$ 113,400,000		$ 2,800,000
New At-the-Market Equity offering programs
Stockholders' Equity
Aggregate value of the shares of common stock to be sold						$ 300,000,000
Contributions - net proceeds from common stock offering (in shares)				895,956	1,626,999
Proceeds from sale of common stock					$ 182,900,000
2015 New At-the-Market Equity Offering Program [Member]
Stockholders' Equity
Aggregate value of the shares of common stock to be sold		$ 300,000,000
Contributions - net proceeds from common stock offering (in shares)				91,180
Proceeds from sale of common stock				$ 12,000,000
Series I Preferred Stock
Stockholders' Equity
Preferred stock, shares outstanding	9,200,000		9,200,000
Dividend rate preferred units (as a percent)	6.50%		6.50%
Perpetual Preferred stock, liquidation preference (in dollars per share)			$ 25
Perpetual Preferred stock, annual dividends per share (in dollars per share)			$ 1.625
Contributions of net proceeds from sale of preferred stock	$ 0

Stockholders' Equity of the C93

Stockholders' Equity of the Company (Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 28, 2015
Stockholders' Equity
Common stock, shares authorized	160,000,000	160,000,000
Issuance of common stock (in shares)			1,626,999
Dividend reinvestments/stock purchases under the DRSPP	$ 0	$ 124,761	$ 185,321
Dividend Reinvestment and Stock Purchase Plan (DRIP)
Stockholders' Equity
Common stock, shares authorized				3,500,000
Issuance of common stock (in shares)	2,687	775,760	608
Dividend reinvestments/stock purchases under the DRSPP	$ 277	$ 99,555	$ 64

Stockholders' Equity of the C94

Stockholders' Equity of the Company (Earnings per Share)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic Earnings:
Income attributable to SL Green common stockholders	$ 234,946	$ 269,132	$ 503,104
Diluted Earnings:
Income attributable to SL Green common stockholders	$ 245,082	$ 279,697	$ 521,571
Basic Shares:
Weighted average common shares outstanding (shares)	100,185,000	99,345,000	95,774,000
Effect of Dilutive Securities:
Redemption of units to common shares (shares)	4,323,000	3,899,000	3,514,000
Stock-based compensation plans (shares)	373,000	490,000	408,000
Diluted weighted average common stock outstanding (shares)	104,881,000	103,734,000	99,696,000
Common stock shares excluded from the diluted shares outstanding (shares)	774,782	263,991	737,361
Common Stock
Effect of Dilutive Securities:
Redemption of units to common shares	$ 10,136	$ 10,565	$ 18,467

Partners' Capital of the Oper95

Partners' Capital of the Operating Partnership (Details)	Dec. 31, 2016shares	Dec. 31, 2015unitshares	Dec. 31, 2014shares	Dec. 31, 2013shares
Common Stock
Stockholders' Equity
Units outstanding (units)	100,562,000	99,976,000	97,325,000	94,993,000
SL Green Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	4.16%
SL Green Operating Partnership | Series I Preferred Units
Stockholders' Equity
Units outstanding (units)	9,200,000
SL Green Operating Partnership | Common Stock
Stockholders' Equity
Units outstanding (units)	100,562,349
SL Green Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)		3.61%
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	4,363,716	3,745,766

Partners' Capital of the Oper96

Partners' Capital of the Operating Partnership - EPS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity
Income attributable to SL Green common stockholders	$ 234,946	$ 269,132	$ 503,104
Weighted average common shares outstanding (shares)	100,185,000	99,345,000	95,774,000
Common stock shares excluded from the diluted shares outstanding (shares)	774,782	263,991	737,361
SL Green Operating Partnership
Stockholders' Equity
Net Income (Loss) Allocated to, Common Unitholders	$ 245,082	$ 279,697	$ 521,571
Weighted average common shares outstanding (shares)	104,508,000	103,244,000	99,288,000
Stock-based compensation plans (shares)	373,000	490,000	408,000
Diluted weighted average common units outstanding (shares)	104,881,000	103,734,000	99,696,000
Common stock shares excluded from the diluted shares outstanding (shares)	774,782	263,991	737,361

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Details)

1 Months Ended

12 Months Ended

Jan. 31, 2015USD ($)

Aug. 31, 2014shares

Aug. 31, 2011USD ($)

Dec. 31, 2016USD ($)unit / sharesfungible_unit$ / sharesshares

Dec. 31, 2015USD ($)shares

Dec. 31, 2014USD ($)shares

Sep. 30, 2014shares

Jun. 30, 2014shares

Dec. 31, 2013shares

Dec. 11, 2013

Dec. 31, 2012shares

Dec. 17, 2012

Dec. 31, 2011shares

Dec. 31, 2010shares

Dec. 31, 2009USD ($)

Jan. 01, 2008shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

$ 6,000,000

$ 6,500,000

$ 6,800,000

Stock options, stock appreciation rights and other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected life of option (in years)

5 years

All other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (in fungible units per share) | unit / shares

1

Expected life of option (in years)

10 years

Stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Expected life of option (in years)

3 years 8 months 12 days

3 years 7 months 6 days

3 years 7 months 6 days

Period of commencement of option vesting, from date of grant (in years)

1 year

Exercise price of options granted, low end of the range (in dollars per share) | $ / shares

$ 20.67

Exercise price of options granted, high end of the range (in dollars per share) | $ / shares

$ 137.18

Remaining weighted average contractual life of the options outstanding (in years)

3 years 8 months 12 days

Remaining weighted average contractual life of the options exercisable (in years)

2 years 10 months 24 days

Total unrecognized compensation cost related to unvested stock awards

$ 13,300,000

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

2 years 1 month 6 days

Weighted average fair value of options granted during the period

$ 8,363,036

$ 9,522,613

$ 2,841,678

Stock options | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period (in years)

5 years

Options vesting period (in years)

1 year

Stock options | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period (in years)

10 years

Options vesting period (in years)

5 years

Class O LTIP Units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Preferred unit distributions as a percentage of common unit distributions

10.00%

Restricted Stock Awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 7,153,966

7,540,747

9,658,019

Total unrecognized compensation cost related to unvested stock awards

$ 21,000,000

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

2 years 8 months 12 days

Annual award vesting rate, low end of range (as a percent)

15.00%

Annual award vesting rate, high end of range (as a percent)

35.00%

Fair value of restricted stock vested during the period

$ 7,600,000

7,400,000

5,500,000

Weighted average fair value of options granted during the period

$ 10,650,077

$ 16,061,201

$ 1,141,675

Awards granted (in shares) | shares

98,800

143,053

9,550

Awards outstanding (in shares) | shares

3,202,031

3,137,881

3,000,979

2,994,197

LTIP units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

1 year 10 months 24 days

Weighted average fair value of options granted during the period

$ 34,900,000

$ 25,400,000

Performance Shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Total unrecognized compensation cost related to unvested stock awards

5,700,000

Share-based Compensation

$ 26,500,000

30,200,000

$ 31,400,000

Employee Stock Purchase Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares of common stock available for issuance (shares) | shares

500,000

Duration of each offering period starting the first day of each calendar quarter (in months)

3 months

Purchase price as a percentage of market value of the common stock (percent)

85.00%

Shares of common stock issued (shares) | shares

95,448

Fourth Amended and Restated 2003 Stock Option and Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum fungible units that may be granted (in shares) | fungible_unit

27,030,000

Fungible units per share (in fungible units per share) | unit / shares

3.74

Shares that may be issued if equal to fungible units (shares) (less than) | shares

27,030,000

Fungible units | fungible_unit

9,500,000

Stock options, stock appreciation rights and other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (in fungible units per share) | unit / shares

0.73

Third Amendment and Restated 2005 Stock Option and Incentive Plan [Member] | Stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 8,900,000

8,000,000

8,100,000

2010 Notional Unit Long-Term Compensation Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

2,700,000

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

$ 31,700,000

Approximate amount of awards that may be earned by recipients after beginning of the second year if maximum performance achieved

$ 25,000,000

Approximate amount of awards that may be earned by recipients after beginning of the third year if maximum performance achieved

$ 25,000,000

Minimum stock price appreciation to earn maximum amount of awards (as a percent)

50.00%

LTIP units earned (in shares) | shares

327,416

327,416

385,583

Percentage of LTIP Units earned, vested (percent)

25.00%

50.00%

2010 Notional Unit Long-Term Compensation Plan | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

$ 15,000,000

2010 Notional Unit Long-Term Compensation Plan | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

$ 75,000,000

2011 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

0

4,500,000

8,600,000

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

26,700,000

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

$ 85,000,000

LTIP units earned (in shares) | shares

280,454

560,908

Value of LTIP Units that could be earned expressed as percentage of outperformance amount in excess of the 30% benchmark (percent)

10.00%

Duration period return to stockholders exceeds 25% (in years)

3 years

Cumulative return to stockholders (percent)

25.00%

Return to stockholders

$ 85,000,000

Performance period (in years)

3 years

2011 Outperformance Plan | Vested on August 31, 2014

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2011 Outperformance Plan | Vesting on August 31, 2015

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2011 Outperformance Plan | Earned anytime after beginning of second year

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

33.33%

2011 Outperformance Plan | Earned any time after beginning of third year

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

66.67%

2014 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

8,400,000

$ 5,900,000

$ 200,000

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

27,900,000

LTIP units earned (in shares) | shares

610,000

Performance period (in years)

3 years

Award period (in years)

3 years

Percentage of LTIP units that may be earned based on the Company's absolute total return to stockholders

66.67%

Percentage of LTIP units that may be earned based on relative total return to stockholders compared to constituents of the MSCI REIT index

33.33%

2014 Outperformance Plan | Vesting on August 31, 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2014 Outperformance Plan | Vesting on August 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

Deferred Stock Compensation Plan for Directors

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 2,100,000

Maximum percentage of the annual retainer fee, chairman fees and meeting fees that may be deferred by non-employee directors (percent)

100.00%

Awards granted (in shares) | shares

9,022

Shares issued (in shares) | shares

9,279

Awards outstanding (in shares) | shares

89,790

Share-based Compensation (Detai

Share-based Compensation (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield (as a percent)	2.37%	1.97%	1.60%
Expected life of option (in years)	3 years 8 months 12 days	3 years 7 months 6 days	3 years 7 months 6 days
Risk-free interest rate (as a percent)	1.57%	1.43%	1.29%
Expected stock price volatility (as a percent)	26.76%	32.34%	33.97%
Options Outstanding
Balance at beginning of year (in shares)	1,595,007	1,462,726	1,765,034
Granted (in shares)	445,100	389,836	102,050
Exercised (in shares)	(192,875)	(217,438)	(348,156)
Lapsed or cancelled (in shares)	(110,019)	(40,117)	(56,202)
Balance at end of period (in shares)	1,737,213	1,595,007	1,462,726
Options exercisable at end of period (in shares)	748,617	589,055	428,951
Weighted average fair value of options granted during the period	$ 8,363,036	$ 9,522,613	$ 2,841,678
Weighted Average Exercise Price
Balance at beginning of year (in dollars per share)	$ 95.52	$ 87.98	$ 83.24
Granted (in dollars per share)	105.86	112.54	119.12
Exercised (in dollars per share)	76.90	74.69	72.76
Lapsed or cancelled (in dollars per share)	123.86	98.61	90.03
Balance at end of period (in dollars per share)	98.44	95.52	87.98
Options exercisable at end of period (in dollars per share)	$ 87.72	$ 89.85	$ 90.32
Restricted Stock Awards
Options Outstanding
Weighted average fair value of options granted during the period	$ 10,650,077	$ 16,061,201	$ 1,141,675
Summary of restricted stock
Balance at beginning of year (in shares)	3,137,881	3,000,979	2,994,197
Granted (in shares)	98,800	143,053	9,550
Cancelled (in shares)	(34,650)	(6,151)	(2,768)
Balance at end of period (in shares)	3,202,031	3,137,881	3,000,979
Vested during the period (in shares)	83,822	87,081	75,043
Compensation expense recorded	$ 7,153,966	$ 7,540,747	$ 9,658,019

Accumulated Other Comprehensi99

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	$ (8,749)
Ending Balance	22,137	$ (8,749)
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(8,749)	(6,980)	$ (15,211)
Other comprehensive loss before reclassifications	18,211	(13,467)	(421)
Amounts reclassified from accumulated other comprehensive income	12,675	11,698	8,652
Ending Balance	22,137	(8,749)	(6,980)
Deferred net losses from terminated hedges	7,100	9,700
SL Green Realty Corp | Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(10,160)	(9,498)	(15,125)
Other comprehensive loss before reclassifications	13,534	(11,143)	(576)
Amounts reclassified from accumulated other comprehensive income	9,222	10,481	6,203
Ending Balance	12,596	(10,160)	(9,498)
SL Green Realty Corp | Unrealized gain (loss) on marketable securities
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	2,003	2,613	4,784
Other comprehensive loss before reclassifications	3,517	(610)	(2,692)
Amounts reclassified from accumulated other comprehensive income	0	0	521
Ending Balance	5,520	2,003	2,613
SL Green Realty Corp | Joint venture | Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(592)	(95)	(4,870)
Other comprehensive loss before reclassifications	1,160	(1,714)	2,847
Amounts reclassified from accumulated other comprehensive income	3,453	1,217	1,928
Ending Balance	$ 4,021	$ (592)	$ (95)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value of Financial Instruments
Marketable securities	$ 85,110		$ 45,138
Interest rate cap and swap agreements (included in other assets)	21,090		204
Interest rate cap and swap agreements (included in accrued interest payable and other liabilities)	1		10,776
Debt and preferred equity investments	1,640,412		1,670,020
Secured Debt, Bearing Variable Interest, Amount	622,585		1,205,494
248-252 Bedford Avenue
Fair Value of Financial Instruments
Secured Debt, Bearing Variable Interest, Amount	0		29,000
Carrying Value (1)
Fair Value of Financial Instruments
Fixed rate debt	5,452,084		7,232,254
Variable rate debt	1,105,585		3,202,494
Total	6,557,669		10,434,748
Fair Value
Fair Value of Financial Instruments
Marketable securities	85,110		45,138
Total	6,832,604		10,770,574
Estimated fair value of debt and preferred equity investments, low end of range	1,600,000		1,700,000
Estimated fair value of debt and preferred equity investments, high end of range	1,800,000		1,800,000
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0		0
Interest rate cap and swap agreements (included in accrued interest payable and other liabilities)	0		0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	21,090		204
Interest rate cap and swap agreements (included in accrued interest payable and other liabilities)	1		10,776
Level 3
Fair Value of Financial Instruments
Marketable securities	0		0
Interest rate cap and swap agreements (included in other assets)	0		0
Interest rate cap and swap agreements (included in accrued interest payable and other liabilities)	0		0
Level 3 | Carrying Value (1)
Fair Value of Financial Instruments
Debt and preferred equity investments			1,670,020
Level 3 | Fair Value
Fair Value of Financial Instruments
Fixed rate debt	5,722,494		7,591,388
Variable rate debt	1,110,110		3,179,186
Equity marketable securities
Fair Value of Financial Instruments
Marketable securities		$ 48,315	4,704
Equity marketable securities | Level 1
Fair Value of Financial Instruments
Marketable securities	48,315		4,704
Mortgage-backed securities
Fair Value of Financial Instruments
Marketable securities		$ 36,795	40,434
Mortgage-backed securities | Level 2
Fair Value of Financial Instruments
Marketable securities	36,795		$ 40,434
248-252 Bedford Avenue | Carrying Value (1)
Fair Value of Financial Instruments
Variable rate debt	$ 29,000

Financial Instruments_ Deriv101

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Instruments: Derivatives and Hedging
Fair Value	$ (1)	$ (10,776)
Fair Value	21,090	204
Derivative, Fair Value, Net	21,089
Gain (loss) from settlement of hedges included in accumulated other comprehensive loss (less than)	472,790	15,000	$ 61,000
Fair value of derivatives in a net liability position	100
Aggregate termination value	100
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months	2,200
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months	1,200
Amount of (Loss) Gain Recognized in Other Comprehensive Loss (Effective Portion)	16,628	(13,386)	2,213
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	11,502	12,157	8,430
Amount of (Loss) or Gain Recognized into Income (Ineffective Portion)	757	(441)	4
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of (Loss) Gain Recognized in Other Comprehensive Loss (Effective Portion)	2,012	(1,779)	2,916
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	1,981	1,265	1,999
Amount of (Loss) or Gain Recognized into Income (Ineffective Portion)	785	(19)	0
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000
Strike Rate (as a percent)	0.9375%
Fair Value	$ 11
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000
Strike Rate (as a percent)	0.94%
Fair Value	$ 5
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000
Strike Rate (as a percent)	0.94%
Fair Value	$ 5
Interest Rate Swap Expiring in January 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 14,409
Strike Rate (as a percent)	0.50%
Fair Value	$ 2
Interest Rate Swap Expiring in February 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 8,018
Strike Rate (as a percent)	0.852%
Fair Value	$ (1)
Interest Rate Cap Expiring in September 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 137,500
Strike Rate (as a percent)	4.00%
Fair Value	$ 0
Interest Rate Swap
Financial Instruments: Derivatives and Hedging
Amount of (Loss) Gain Recognized in Other Comprehensive Loss (Effective Portion)	14,616	(11,607)	(703)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	9,521	10,892	6,431
Amount of (Loss) or Gain Recognized into Income (Ineffective Portion)	(28)	$ (422)	$ 4
Interest Rate Cap Expiring in May 2017 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 1,450,000
Strike Rate (as a percent)	4.75%
Fair Value	$ 0
Interest Rate Swap Expiring in July 2023 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000
Strike Rate (as a percent)	1.131%
Fair Value	$ 10,293
Interest Rate Swap Expiring in July 2023, 2 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000
Strike Rate (as a percent)	1.161%
Fair Value	$ 4,963
Interest Rate Cap Expiring in October 2017 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 23,199
Strike Rate (as a percent)	4.50%
Fair Value	$ 0
Interest Rate Swap Expiring in December 2026 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 5,000
Strike Rate (as a percent)	2.1595%
Fair Value	$ 77
Interest Rate Swap Expiring in January 2027 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 225,000
Strike Rate (as a percent)	2.185%
Fair Value	$ 3,223
Interest Rate Swap Expiring in January 2027, 2 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 25,000
Strike Rate (as a percent)	2.185%
Fair Value	$ 358
Interest Rate Swap Expiring in January 2027, 3 [Member]
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000
Strike Rate (as a percent)	2.1825%
Fair Value	$ 2,153

Rental Income (Details)

Rental Income (Details) $ in Thousands	Dec. 31, 2016USD ($)
Consolidated properties
Operating Leased Assets [Line Items]
2,016	$ 1,271,232
2,017	1,256,047
2,018	1,161,772
2,019	1,120,476
2,020	976,638
Thereafter	8,062,838
Total minimum lease payments	13,849,003
Unconsolidated properties
Operating Leased Assets [Line Items]
2,016	198,304
2,017	203,934
2,018	195,888
2,019	190,139
2,020	184,367
Thereafter	1,389,446
Total minimum lease payments	$ 2,362,078

Benefit Plans (Details)

Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2000
Multiemployer Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution of Specified Percentage of Annual Compensation	50.00%		50.00%		50.00%
Plan contributions	$ 17,092,000		$ 17,184,000		$ 17,115,000
401 (K) Plan
Employee contribution limit per calendar year (percentage)	15.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%						50.00%
Defined Contribution Plan, Employer Match Employee Contribution	6.00%		6.00%		6.00%
Percentage of eligible compensation matched by employer (percentage)	6.00%						4.00%
Matching contribution	$ 566,000		$ 550,000		$ 550,000
Health Plan
Multiemployer Plans [Line Items]
Plan contributions	$ 11,530,000		8,736,000		8,470,000
Multiemployer Plan, Period Contributions		$ 1,200,000,000		$ 1,100,000,000		$ 1,000,000,000
Multiemployer Plans, Collective-Bargaining Arrangement, Percentage of Contributions	5.00%
Other plans
Multiemployer Plans [Line Items]
Plan contributions	$ 1,583,000		5,716,000		5,838,000
Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Multiemployer Plans, Surcharge	No
Plan contributions	$ 3,979,000	$ 0	$ 2,732,000	$ 0	$ 2,807,000	$ 226,700,000
Multiemployer Plans, Contributions By Employer, Percent	5.00%

Commitments and Contingencie104

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)extenstion_option	Dec. 31, 2015USD ($)
Other Commitments [Line Items]
Employment agreements with certain executives, minimum cash-based compensation for next fiscal year	$ 5,200
Employment agreements with certain executives, grant date value of deferred compensation awards	1,600
Capital lease obligations	$ 42,132	$ 41,360
Number of renewal options available (extension option)	2
Cost basis	$ 47,445	47,445
Term of first renewal option (in years)	35 years
Initial term of non cancellable operating leases, minimum (in years)	1 year
Capital lease
2,017	$ 2,387
2,017	2,387
2,018	2,411
2,019	2,620
2,020	2,794
Thereafter	822,688
Total minimum lease payments	835,287
Less amount representing interest	(793,155)
Capital lease obligations	42,132
Non-cancellable operating leases
2,017	31,049
2,017	31,049
2,018	31,066
2,019	31,436
2,020	31,628
Thereafter	732,724
Total minimum lease payments	$ 888,952
30 East 40th Street
Other Commitments [Line Items]
Land as percentage of fair market value of property under lease	63.60%
Capital lease obligations	$ 20,000
420 Lexington Avenue
Other Commitments [Line Items]
Land as percentage of fair market value of property under lease	6.00%
Annual ground lease payments through December 2019	$ 10,900
Annual ground lease payments through December 2029	11,200
Annual ground lease payments due thereafter	$ 12,300
1080 Amsterdam Avenue
Other Commitments [Line Items]
Land as percentage of fair market value of property under lease	40.00%
Non-cancellable operating leases
Total minimum lease payments	$ 41,600
711 Third Avenue
Other Commitments [Line Items]
Percentage of the fee not owned by the entity (percent)	50.00%
711 Third Avenue | Through July 2016
Other Commitments [Line Items]
Required annual ground lease payments	$ 5,250
711 Third Avenue | After July 2016
Other Commitments [Line Items]
Required annual ground lease payments	$ 5,500
461 Fifth Avenue
Other Commitments [Line Items]
Number of renewal options available (extension option) | extenstion_option	2
Required annual ground lease payments	$ 2,100
Term of first renewal option (in years)	21 years
Term of second renewal option (in years)	21 years
Term of third renewal option (in years)	15 years
625 Madison Avenue
Other Commitments [Line Items]
Number of renewal options available (extension option) | extenstion_option	2
Required annual ground lease payments	$ 4,600
Term of first renewal option (in years)	23 years
Term of second renewal option (in years)	23 years
1185 Avenue of the Americas
Other Commitments [Line Items]
Required annual ground lease payments	$ 6,900
Term of first renewal option (in years)	23 years
Belmont
Other Commitments [Line Items]
Loss reserves	$ 6,300	$ 6,400
TRIPRA 2,015
Other Commitments [Line Items]
Program trigger	120,000
Per annum increase	$ 20,000
Coinsurance Percentage, TRIPRA	16.00%
Coinsurance Percentage, Annual Increase, TRIPRA	1.00%

Segment Information (Details)

Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment information
Number of reportable segments (segment) | segment	2
Total revenues	$ 1,863,981	$ 1,662,829	$ 1,519,978
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and (loss) gain on sale of marketable securities	7,256	90,289	201,500
Total assets	15,857,787	19,727,646
Marketing, general and administrative	99,759	94,873	92,488
Operating Segments | Real Estate Segment
Segment information
Total revenues	1,629,919	1,465,881	1,320,777
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and (loss) gain on sale of marketable securities	(203,988)	(78,681)	31,805
Total assets	13,868,085	17,765,854
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues	234,062	196,948	199,201
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and (loss) gain on sale of marketable securities	211,244	168,970	$ 169,695
Total assets	$ 1,989,702	$ 1,961,792

Segment Information (Schedule o

Segment Information (Schedule of Reconciliation of Income from Continuing Operations to Net Income Attributable to SL Green Common Stockholders)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves, loss on early extinguishment of debt, and loss (gain) on sale of marketable securities	$ 7,256	$ 90,289	$ 201,500
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	44,009	15,844	123,253
Purchase price fair value adjustment	0	40,078	67,446
Gain on sale of real estate, net	238,116	175,974	0
Depreciable real estate reserves	(10,387)	(19,226)	0
Loss on early extinguishment of debt	0	(49)	(32,365)
(Loss) gain on sale of investment in marketable securities	(83)	0	3,895
Income from continuing operations	278,911	302,910	363,729
Net income from discontinued operations	0	427	19,075
Gain on sale of discontinued operations	0	14,122	163,059
Net income	$ 278,911	$ 317,459	$ 545,863

Quarterly Financial Data of 107

Quarterly Financial Data of the Company (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Total revenues									$ 1,863,981	$ 1,662,829	$ 1,519,978
Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and gain (loss) on early extinguishment of debt									(4,618)	77,261	174,963
Equity in net income from unconsolidated joint ventures	$ (95)	$ (3,968)	$ 5,841	$ 10,096	$ 2,377	$ 3,627	$ 2,994	$ 4,030	11,874	13,028	26,537
Equity in net gain on sale of interest in unconsolidated joint venture/real estate									44,009	15,844	123,253
Purchase price fair value adjustment									0	38,563	65,059
Gain on sale of real estate, net									238,116	175,974	0
Depreciable real estate reserves									(10,387)	(19,226)	0
Change in unrealized gain (loss) on marketable securities									3,677	(607)	(2,237)
Loss on early extinguishment of debt									0	(49)	(32,365)
Net income from discontinued operations									0	427	19,075
Gain on sale of discontinued operations									0	14,122	163,059
Net income (loss) attributable to SL Green/SLGOP									249,896	284,084	518,056
Perpetual preferred stock dividends									(14,950)	(14,952)	(14,952)
Net income attributable to SL Green common stockholders									$ 234,946	$ 269,132	$ 503,104
Net income (loss) attributable to common stockholders per common share - basic (usd per share)									$ 2.35	$ 2.71	$ 5.25
Net income (loss) attributable to common stockholders per common share - diluted (usd per share)									$ 2.34	$ 2.70	$ 5.23
SL Green Realty Corp
Condensed Income Statements, Captions [Line Items]
Total revenues	374,242	416,681	617,614	455,444	425,390	432,066	409,074	396,299
Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and gain (loss) on early extinguishment of debt	26,278	46,689	(76,304)	(1,281)	54,591	17,367	(32,942)	38,245
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	421	225	33,448	9,915	(206)	15,281	769	0
Purchase price fair value adjustment					40,078	0	0	0
Gain on sale of real estate, net	27,366	397	196,580	13,773	16,270	159,704	0	0
Depreciable real estate reserves	0	0	(10,387)	0	0	(19,226)	0	0
Change in unrealized gain (loss) on marketable securities	0	0	(83)	0
Distributions Preferred Units	(6,217)	(5,353)	(11,901)	(5,544)	(9,208)	(9,357)	(6,189)	(8,621)
Loss on early extinguishment of debt					0	0	0	(49)
Net income from discontinued operations					0	0	0	427
Gain on sale of discontinued operations					1,139	0	0	12,983
Net income (loss) attributable to SL Green/SLGOP	47,753	37,990	137,194	26,959	105,041	167,396	(35,368)	47,015
Perpetual preferred stock dividends	(3,737)	(3,738)	(3,737)	(3,738)	(3,738)	(3,738)	(3,738)	(3,738)
Net income attributable to SL Green common stockholders	$ 44,016	$ 34,252	$ 133,457	$ 23,221	$ 101,303	$ 163,658	$ (39,106)	$ 43,277
Net income (loss) attributable to common stockholders per common share - basic (usd per share)	$ 0.44	$ 0.34	$ 1.33	$ 0.23	$ 1.02	$ 1.64	$ (0.39)	$ 0.44
Net income (loss) attributable to common stockholders per common share - diluted (usd per share)	$ 0.44	$ 0.34	$ 1.33	$ 0.23	$ 1.01	$ 1.64	$ (0.39)	$ 0.44

Quarterly Financial Data of 108

Quarterly Financial Data of the Operating Partnership (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Income Statements, Captions [Line Items]
Total revenues									$ 1,863,981	$ 1,662,829	$ 1,519,978
Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and gain (loss) on early extinguishment of debt									(4,618)	77,261	174,963
Equity in net income from unconsolidated joint ventures	$ (95)	$ (3,968)	$ 5,841	$ 10,096	$ 2,377	$ 3,627	$ 2,994	$ 4,030	11,874	13,028	26,537
Equity in net gain on sale of interest in unconsolidated joint venture/real estate									44,009	15,844	123,253
Purchase price fair value adjustment									0	38,563	65,059
Gain on sale of real estate									238,116	175,974	0
Depreciable real estate reserves									(10,387)	(19,226)	0
Loss on early extinguishment of debt									0	(49)	(32,365)
Net income (loss) attributable to SL Green/SLGOP									249,896	284,084	518,056
Net income from discontinued operations									0	427	19,075
Gain on sale of discontinued operations									0	14,122	163,059
Preferred stock/unit redemption costs									$ 0	$ 0	$ 0
Net income (loss) attributable to common stockholders per common share - diluted (usd per share)									$ 2.34	$ 2.70	$ 5.23
SL Green Operating Partnership
Condensed Income Statements, Captions [Line Items]
Total revenues	374,242	416,681	617,614	455,444	425,390	432,066	409,074	396,299	$ 1,863,981	$ 1,662,829	$ 1,519,978
Income (loss) from continuing operations before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain on sale of real estate, depreciable real estate reserves and gain (loss) on early extinguishment of debt	26,278	46,689	(76,304)	(1,281)	54,591	17,367	(32,942)	38,245	(4,618)	77,261	174,963
Equity in net income from unconsolidated joint ventures	(95)	(3,968)	5,841	10,096	2,377	3,627	2,994	4,030	11,874	13,028	26,537
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	421	225	33,448	9,915	(206)	15,281	769	0	44,009	15,844	123,253
Purchase price fair value adjustment					40,078	0	0	0	0	40,078	67,446
Gain on sale of real estate	27,366	397	196,580	13,773	16,270	159,704	0	0	238,116	175,974	0
Depreciable real estate reserves	0	0	(10,387)	0	0	(19,226)	0	0	(10,387)	(19,226)	0
Loss on early extinguishment of debt	0		(83)		0	0	0	(49)	0	(49)	(32,365)
Distributions Preferred Units	(4,252)	(3,690)	(6,315)	(4,622)	(5,277)	(2,890)	(7,766)	(6,878)	(14,950)	(14,952)	(14,952)
Net income (loss) attributable to SL Green/SLGOP	49,718	39,653	142,780	27,881	108,972	173,863	(36,945)	48,758	260,032	294,649	536,523
Net income from discontinued operations					0	0	0	427	0	427	19,075
Gain on sale of discontinued operations					1,139	0	0	12,983	0	14,122	163,059
Preferred stock/unit redemption costs									0	0	0
Perpetual preferred distributions	3,737	3,738	3,737	3,738	(3,738)	(3,738)	(3,738)	(3,738)	(14,950)	(14,952)	(14,952)
Net income attributable to SLGOP common unitholders	$ 45,981	$ 35,915	$ 139,043	$ 24,143	$ 105,234	$ 170,125	$ (40,683)	$ 45,020	$ 245,082	$ 279,697	$ 521,571
Net income attributable to common unitholders per common unit - basic (usd per share)	$ 0.44	$ 0.34	$ 1.33	$ 0.23					$ 2.35	$ 2.71	$ 5.25
Net income attributable to common unitholders per common share - diluted (usd per share)	$ 0.44	$ 0.34	$ 1.33	$ 0.23	$ 1.02	$ 1.64	$ (0.39)	$ 0.44	$ 2.34	$ 2.70	$ 5.23
Net income (loss) attributable to common stockholders per common share - diluted (usd per share)					$ 1.01	$ 1.64	$ (0.39)	$ 0.44

Schedule II - Valuation and 109

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tenant and other receivables—allowance
Changes in valuation allowance
Balance at Beginning of Year	$ 17,618	$ 18,068	$ 17,325
Additions Charged Against Operations	10,630	8,139	13,533
Uncollectible Accounts Written-off/Recovery	(11,656)	(8,589)	(12,790)
Balance at End of Year	16,592	17,618	18,068
Deferred rent receivable—allowance
Changes in valuation allowance
Balance at Beginning of Year	21,730	27,411	30,333
Additions Charged Against Operations	13,620	2,789	4,140
Uncollectible Accounts Written-off/Recovery	(10,147)	(8,470)	(7,062)
Balance at End of Year	$ 25,203	$ 21,730	$ 27,411

Schedule III - Real Estate A110

Schedule III - Real Estate And Accumulated Depreciation (Details) - USD ($) $ in Thousands	1 Months Ended
	May 31, 2010	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 3,731,070
Initial Cost
Land		3,175,339
Building & Improvements		7,760,729
Cost Capitalized Subsequent To Acquisition
Land		134,371
Building & Improvements		1,672,893
Gross Amount at Which Carried at Close of Period
Land		3,309,710
Building & Improvements		9,433,622
Total		12,743,332	$ 16,681,602	$ 14,069,141	$ 12,333,780
Accumulated Depreciation		2,264,694	$ 2,060,706	$ 1,905,165	$ 1,646,240
420 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		300,000
Initial Cost
Land		0
Building & Improvements		107,832
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		239,911
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		347,743
Total		347,743
Accumulated Depreciation		139,418
711 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		19,844
Building & Improvements		42,499
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		57,916
Gross Amount at Which Carried at Close of Period
Land		19,844
Building & Improvements		100,415
Total		120,259
Accumulated Depreciation		$ 34,418
Interest in property (as a percent)		50.00%
Third Avenue, 919 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 500,000
Initial Cost
Land		223,529
Building & Improvements		1,033,198
Cost Capitalized Subsequent To Acquisition
Land		35,410
Building & Improvements		42,038
Gross Amount at Which Carried at Close of Period
Land		258,939
Building & Improvements		1,075,236
Total		1,334,175
Accumulated Depreciation		$ 274,778
Interest in property (as a percent)		51.00%
555 W. 57th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		18,846
Building & Improvements		78,704
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		59,564
Gross Amount at Which Carried at Close of Period
Land		18,846
Building & Improvements		138,268
Total		157,114
Accumulated Depreciation		58,187
220 East 42nd Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		275,000
Initial Cost
Land		50,373
Building & Improvements		203,727
Cost Capitalized Subsequent To Acquisition
Land		635
Building & Improvements		85,907
Gross Amount at Which Carried at Close of Period
Land		51,008
Building & Improvements		289,634
Total		340,642
Accumulated Depreciation		90,730
461 Fifth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		0
Building & Improvements		62,695
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		10,723
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		73,418
Total		73,418
Accumulated Depreciation		26,105
750 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		51,093
Building & Improvements		205,972
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		39,436
Gross Amount at Which Carried at Close of Period
Land		51,093
Building & Improvements		245,408
Total		296,501
Accumulated Depreciation		85,282
625 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		0
Building & Improvements		246,673
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		41,937
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		288,610
Total		288,610
Accumulated Depreciation		97,690
485 Lexington Avenue (3)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		450,000
Initial Cost
Land		77,517
Building & Improvements		326,825
Cost Capitalized Subsequent To Acquisition
Land		765
Building & Improvements		94,646
Gross Amount at Which Carried at Close of Period
Land		78,282
Building & Improvements		421,471
Total		499,753
Accumulated Depreciation		155,321
609 Fifth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		36,677
Building & Improvements		145,954
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		8,270
Gross Amount at Which Carried at Close of Period
Land		36,677
Building & Improvements		154,224
Total		190,901
Accumulated Depreciation		41,993
810 Seventh Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		114,077
Building & Improvements		476,386
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		65,985
Gross Amount at Which Carried at Close of Period
Land		114,077
Building & Improvements		542,371
Total		656,448
Accumulated Depreciation		145,216
1185 Avenue of the Americas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		0
Building & Improvements		728,213
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		39,403
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		767,616
Total		767,616
Accumulated Depreciation		221,415
1350 Avenue of the Americas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		91,038
Building & Improvements		380,744
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		37,736
Gross Amount at Which Carried at Close of Period
Land		91,038
Building & Improvements		418,480
Total		509,518
Accumulated Depreciation		114,264
1100 King Street - 1 to 7 International Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		49,392
Building & Improvements		104,376
Cost Capitalized Subsequent To Acquisition
Land		(24,004)
Building & Improvements		23,954
Gross Amount at Which Carried at Close of Period
Land		25,388
Building & Improvements		128,330
Total		153,718
Accumulated Depreciation		35,062
520 White Plains Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		6,324
Building & Improvements		26,096
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		6,602
Gross Amount at Which Carried at Close of Period
Land		6,324
Building & Improvements		32,698
Total		39,022
Accumulated Depreciation		9,158
115-117 Stevens Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		5,933
Building & Improvements		23,826
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		5,390
Gross Amount at Which Carried at Close of Period
Land		5,933
Building & Improvements		29,216
Total		35,149
Accumulated Depreciation		7,622
100 Summit Lake Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		10,526
Building & Improvements		43,109
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		8,476
Gross Amount at Which Carried at Close of Period
Land		10,526
Building & Improvements		51,585
Total		62,111
Accumulated Depreciation		15,149
200 Summit Lake Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		11,183
Building & Improvements		47,906
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		10,448
Gross Amount at Which Carried at Close of Period
Land		11,183
Building & Improvements		58,354
Total		69,537
Accumulated Depreciation		16,543
500 Summit Lake Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		9,777
Building & Improvements		39,048
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		5,290
Gross Amount at Which Carried at Close of Period
Land		9,777
Building & Improvements		44,338
Total		54,115
Accumulated Depreciation		11,672
360 Hamilton Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		29,497
Building & Improvements		118,250
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		13,844
Gross Amount at Which Carried at Close of Period
Land		29,497
Building & Improvements		132,094
Total		161,591
Accumulated Depreciation		35,784
1-6 Landmark Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		100,000
Initial Cost
Land		50,947
Building & Improvements		195,167
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		45,253
Gross Amount at Which Carried at Close of Period
Land		50,947
Building & Improvements		240,420
Total		291,367
Accumulated Depreciation		61,359
7 Landmark Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		2,088
Building & Improvements		7,748
Cost Capitalized Subsequent To Acquisition
Land		(367)
Building & Improvements		670
Gross Amount at Which Carried at Close of Period
Land		1,721
Building & Improvements		8,418
Total		10,139
Accumulated Depreciation		1,032
680 Washington Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		11,696
Building & Improvements		45,364
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		10,126
Gross Amount at Which Carried at Close of Period
Land		11,696
Building & Improvements		55,490
Total		67,186
Accumulated Depreciation		$ 14,462
Interest in property (as a percent)		51.00%
750 Washington Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		16,916
Building & Improvements		68,849
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		8,350
Gross Amount at Which Carried at Close of Period
Land		16,916
Building & Improvements		77,199
Total		94,115
Accumulated Depreciation		$ 19,727
Interest in property (as a percent)		51.00%
1010 Washington Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		7,747
Building & Improvements		30,423
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		6,598
Gross Amount at Which Carried at Close of Period
Land		7,747
Building & Improvements		37,021
Total		44,768
Accumulated Depreciation		9,722
400 Summit Lake Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		38,889
Building & Improvements		1
Cost Capitalized Subsequent To Acquisition
Land		285
Building & Improvements		2
Gross Amount at Which Carried at Close of Period
Land		39,174
Building & Improvements		3
Total		39,177
Accumulated Depreciation		0
1055 Washington Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		13,516
Building & Improvements		53,228
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		7,559
Gross Amount at Which Carried at Close of Period
Land		13,516
Building & Improvements		60,787
Total		74,303
Accumulated Depreciation		15,655
1 Madison Ave
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		517,806
Initial Cost
Land		172,641
Building & Improvements		654,394
Cost Capitalized Subsequent To Acquisition
Land		905
Building & Improvements		15,381
Gross Amount at Which Carried at Close of Period
Land		173,546
Building & Improvements		669,775
Total		843,321
Accumulated Depreciation		158,913
125 Chubb Way
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		5,884
Building & Improvements		25,958
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		25,556
Gross Amount at Which Carried at Close of Period
Land		5,884
Building & Improvements		51,514
Total		57,398
Accumulated Depreciation		9,170
100 Church Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		221,446
Initial Cost
Land		32,494
Building & Improvements		79,996
Cost Capitalized Subsequent To Acquisition
Land		2,500
Building & Improvements		90,141
Gross Amount at Which Carried at Close of Period
Land		34,994
Building & Improvements		170,137
Total		205,131
Accumulated Depreciation		40,466
125 Park Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		120,900
Building & Improvements		189,714
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		68,264
Gross Amount at Which Carried at Close of Period
Land		120,900
Building & Improvements		257,978
Total		378,878
Accumulated Depreciation		54,736
885 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		267,650
Initial Cost
Land		131,766
Building & Improvements		0
Cost Capitalized Subsequent To Acquisition
Land		110,771
Building & Improvements		0
Gross Amount at Which Carried at Close of Period
Land		242,537
Building & Improvements		0
Total		242,537
Accumulated Depreciation		0
Williamsburg
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		3,677
Building & Improvements		14,708
Cost Capitalized Subsequent To Acquisition
Land		2,523
Building & Improvements		(4,550)
Gross Amount at Which Carried at Close of Period
Land		6,200
Building & Improvements		10,158
Total		16,358
Accumulated Depreciation		1,604
1515 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		888,531
Initial Cost
Land		462,700
Building & Improvements		707,938
Cost Capitalized Subsequent To Acquisition
Land		1,145
Building & Improvements		136,457
Gross Amount at Which Carried at Close of Period
Land		463,845
Building & Improvements		844,395
Total		1,308,240
Accumulated Depreciation		137,847
110 East 42nd Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		34,000
Building & Improvements		46,411
Cost Capitalized Subsequent To Acquisition
Land		2,354
Building & Improvements		21,634
Gross Amount at Which Carried at Close of Period
Land		36,354
Building & Improvements		68,045
Total		104,399
Accumulated Depreciation		15,275
East 400 Street 58 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		40,000
Initial Cost
Land		17,549
Building & Improvements		30,916
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		7,048
Gross Amount at Which Carried at Close of Period
Land		17,549
Building & Improvements		37,964
Total		55,513
Accumulated Depreciation		$ 4,199
Interest in property (as a percent)		90.00%
752 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		282,415
Building & Improvements		7,131
Cost Capitalized Subsequent To Acquisition
Land		1,871
Building & Improvements		10
Gross Amount at Which Carried at Close of Period
Land		284,286
Building & Improvements		7,141
Total		291,427
Accumulated Depreciation		1,068
762 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		7,694
Initial Cost
Land		6,153
Building & Improvements		10,461
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		90
Gross Amount at Which Carried at Close of Period
Land		6,153
Building & Improvements		10,551
Total		16,704
Accumulated Depreciation		$ 1,359
Interest in property (as a percent)		90.00%
19-21 East 65th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		0
Building & Improvements		7,389
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		148
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		7,537
Total		7,537
Accumulated Depreciation		$ 947
Interest in property (as a percent)		90.00%
304 Park Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		54,189
Building & Improvements		75,619
Cost Capitalized Subsequent To Acquisition
Land		300
Building & Improvements		11,792
Gross Amount at Which Carried at Close of Period
Land		54,489
Building & Improvements		87,411
Total		141,900
Accumulated Depreciation		13,322
635 Sixth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		24,180
Building & Improvements		37,158
Cost Capitalized Subsequent To Acquisition
Land		163
Building & Improvements		50,189
Gross Amount at Which Carried at Close of Period
Land		24,343
Building & Improvements		87,347
Total		111,690
Accumulated Depreciation		4,428
641 Sixth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		45,668
Building & Improvements		67,316
Cost Capitalized Subsequent To Acquisition
Land		308
Building & Improvements		3,076
Gross Amount at Which Carried at Close of Period
Land		45,976
Building & Improvements		70,392
Total		116,368
Accumulated Depreciation		9,339
1080 Amsterdam (13)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		3,525
Initial Cost
Land		0
Building & Improvements		27,445
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		20,521
Gross Amount at Which Carried at Close of Period
Land		0
Building & Improvements		47,966
Total		47,966
Accumulated Depreciation		$ 2,950
Interest in property (as a percent)		92.50%
16 Court
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		19,217
Building & Improvements		63,210
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		16,092
Gross Amount at Which Carried at Close of Period
Land		19,217
Building & Improvements		79,302
Total		98,519
Accumulated Depreciation		10,366
315 West 33rd Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		195,834
Building & Improvements		164,429
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		8,919
Gross Amount at Which Carried at Close of Period
Land		195,834
Building & Improvements		173,348
Total		369,182
Accumulated Depreciation		15,160
562 Fifth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		57,052
Building & Improvements		10,487
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		1,213
Gross Amount at Which Carried at Close of Period
Land		57,052
Building & Improvements		11,700
Total		68,752
Accumulated Depreciation		2,735
719 Seventh Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		37,388
Initial Cost
Land		41,850
Building & Improvements		0
Cost Capitalized Subsequent To Acquisition
Land		1,288
Building & Improvements		27,265
Gross Amount at Which Carried at Close of Period
Land		43,138
Building & Improvements		27,265
Total		70,403
Accumulated Depreciation		$ 0
Interest in property (as a percent)		75.00%
115 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		11,078
Building & Improvements		44,799
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		1,686
Gross Amount at Which Carried at Close of Period
Land		11,078
Building & Improvements		46,485
Total		57,563
Accumulated Depreciation		2,918
635 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		205,632
Building & Improvements		15,805
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		0
Gross Amount at Which Carried at Close of Period
Land		205,632
Building & Improvements		15,805
Total		221,437
Accumulated Depreciation		910
102 Greene Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		8,215
Building & Improvements		26,717
Cost Capitalized Subsequent To Acquisition
Land		35
Building & Improvements		482
Gross Amount at Which Carried at Close of Period
Land		8,250
Building & Improvements		27,199
Total		35,449
Accumulated Depreciation		888
1640 Flatbush Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		6,226
Building & Improvements		501
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		127
Gross Amount at Which Carried at Close of Period
Land		6,226
Building & Improvements		628
Total		6,854
Accumulated Depreciation		22
One Vanderbilt
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		64,030
Initial Cost
Land		80,069
Building & Improvements		116,557
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		191,441
Gross Amount at Which Carried at Close of Period
Land		80,069
Building & Improvements		307,998
Total		388,067
Accumulated Depreciation		0
Upper East Side Residential
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		48,152
Building & Improvements		0
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		0
Gross Amount at Which Carried at Close of Period
Land		48,152
Building & Improvements		0
Total		48,152
Accumulated Depreciation		$ 0
Interest in property (as a percent)		95.10%
110 Greene Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 0
Initial Cost
Land		45,120
Building & Improvements		215,470
Cost Capitalized Subsequent To Acquisition
Land		0
Building & Improvements		3,985
Gross Amount at Which Carried at Close of Period
Land		45,120
Building & Improvements		219,455
Total		264,575
Accumulated Depreciation		$ 9,459
Interest in property (as a percent)		90.00%
187 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		$ 8,400
Initial Cost
Land		7,600
Building & Improvements		9,412
Cost Capitalized Subsequent To Acquisition
Land		(266)
Building & Improvements		(262)
Gross Amount at Which Carried at Close of Period
Land		7,334
Building & Improvements		9,150
Total		16,484
Accumulated Depreciation		3,145
5- 7 Dey Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		31,600
Initial Cost
Land		13,400
Building & Improvements		34,175
Cost Capitalized Subsequent To Acquisition
Land		(468)
Building & Improvements		(5)
Gross Amount at Which Carried at Close of Period
Land		12,932
Building & Improvements		34,170
Total		47,102
Accumulated Depreciation		11,704
30 East 40th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		4,650
Building & Improvements		20,000
Cost Capitalized Subsequent To Acquisition
Land		2
Building & Improvements		1,031
Gross Amount at Which Carried at Close of Period
Land		4,652
Building & Improvements		21,031
Total		25,683
Accumulated Depreciation		295
600 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		81,670
Building & Improvements		182,447
Cost Capitalized Subsequent To Acquisition
Land		(2,166)
Building & Improvements		(1,607)
Gross Amount at Which Carried at Close of Period
Land		79,504
Building & Improvements		180,840
Total		260,344
Accumulated Depreciation		$ 6,443
Ownership interest acquired (percent)	55.00%
Acquisition Price	$ 193,000
Ownership interest in consolidated joint venture (as a percent)		45.00%
Value of interest		$ 277,300
183 Broadway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		18,000
Initial Cost
Land		5,799
Building & Improvements		23,431
Cost Capitalized Subsequent To Acquisition
Land		385
Building & Improvements		715
Gross Amount at Which Carried at Close of Period
Land		6,184
Building & Improvements		24,146
Total		30,330
Accumulated Depreciation		4,591
Other
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances		0
Initial Cost
Land		2,134
Building & Improvements		7,922
Cost Capitalized Subsequent To Acquisition
Land		(3)
Building & Improvements		20
Gross Amount at Which Carried at Close of Period
Land		2,131
Building & Improvements		7,942
Total		10,073
Accumulated Depreciation		$ 2,671

Schedule III - Real Estate A111

Schedule III - Real Estate And Accumulated Depreciation (Activity in Real Estate and Accumulated Depreciation)(Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in real estate
Balance at beginning of year	$ 16,681,602	$ 14,069,141
Property acquisitions	29,230	3,064,137	$ 2,428,259
Improvements	426,060	396,555	379,295
Retirements/disposals/deconsolidation	(4,393,560)	(848,231)	(1,072,193)
Balance at end of year	12,743,332	16,681,602	14,069,141
Aggregate cost of land, buildings and improvements before depreciation	9,200,000
Changes in accumulated depreciation
Balance at beginning of year	2,060,706	1,905,165
Depreciation for year	353,502	480,523	307,823
Retirements/disposals/deconsolidation	(149,514)	(324,982)	(48,898)
Balance at end of year	$ 2,264,694	$ 2,060,706	$ 1,905,165