Reckson Operating Partnership 10-Q 14 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Nov. 14, 2017
Document and Entity Information
Entity Registrant Name	RECKSON OPERATING PARTNERSHIP LP
Entity Central Index Key	930,810
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		0
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Commercial real estate properties, at cost:
Land and land interests	$ 1,735,463	$ 1,805,198
Building and improvements	4,385,489	4,629,994
Building leasehold and improvements	1,073,703	1,073,678
Commercial real estate properties, gross	7,194,655	7,508,870
Less: accumulated depreciation	(1,499,878)	(1,437,222)
Total commercial real estate properties, net	5,694,777	6,071,648
Assets held for sale	127,663	0
Cash and cash equivalents	36,014	59,930
Restricted cash	79,751	43,489
Tenant and other receivables, net of allowance of $7,051 and $4,879 in 2017 and 2016, respectively	28,824	30,999
Deferred rents receivable, net of allowance of $14,290 and $17,798 in 2017 and 2016, respectively	237,634	238,447
Debt and preferred equity investments, net of discounts and deferred origination fees of $24,782 and $16,705 in 2017 and 2016, respectively	2,020,739	1,640,412
Investments in unconsolidated joint ventures	128,794	174,127
Deferred costs, net of accumulated amortization of $76,081 and $73,673 in 2017 and 2016, respectively	109,523	121,470
Other assets	289,841	374,091
Total assets	8,753,560	8,754,613
Liabilities
Mortgages and other loans payable, net	922,049	676,068
Revolving credit facility, net	275,832	0
Unsecured term loan, net	796,284	795,260
Unsecured notes, net	1,180,506	1,179,521
Accrued interest payable	13,418	15,781
Other liabilities	94,426	160,982
Accounts payable and accrued expenses	53,989	60,855
Related party payables	23,808	23,808
Deferred revenue	156,757	161,772
Deferred land leases payable	1,865	1,795
Dividends payable	807	754
Security deposits	40,333	40,033
Liabilities related to assets held for sale	1,141	0
Total liabilities	3,561,215	3,116,629
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	109,161	109,161
Commitments and contingencies	0	0
Capital
General partner capital	4,757,415	5,139,842
Accumulated other comprehensive loss	(1,349)	(1,618)
Total ROP partner's capital	4,756,066	5,138,224
Noncontrolling interests in other partnerships	327,118	390,599
Total capital	5,083,184	5,528,823
Total liabilities and capital	$ 8,753,560	$ 8,754,613

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Tenant and other receivables, net of allowance of $7,051 and $4,879 in 2017 and 2016, respectively	$ 7,051	$ 4,879
Deferred rents receivable, net of allowance of $14,290 and $17,798 in 2017 and 2016, respectively	14,290	17,798
Debt and preferred equity investments, net of discounts and deferred origination fees of $24,782 and $16,705 in 2017 and 2016, respectively	24,782	16,705
Deferred costs, net of accumulated amortization of $76,081 and $73,673 in 2017 and 2016, respectively	76,081	73,673
Land and land interests	1,735,463	1,805,198
Building and improvements	4,385,489	4,629,994
Accumulated depreciation	1,499,878	1,437,222
Other assets	289,841	374,091
Real estate debt, net	922,049	676,068
Accrued interest payable	13,418	15,781
Other liabilities	94,426	160,982
Variable Interest Entity
Land and land interests	268,600	297,300
Building and improvements	1,300,000	1,400,000
Accumulated depreciation	312,500	318,400
Other assets	140,600	160,500
Real estate debt, net	494,700	494,000
Accrued interest payable	2,100	2,100
Other liabilities	$ 51,000	$ 61,400

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Rental revenue, net	$ 167,346	$ 166,456	$ 502,376	$ 486,350
Escalation and reimbursement	25,721	28,158	73,163	78,173
Investment income	47,946	75,715	148,924	175,481
Other income	895	1,007	1,612	2,754
Total revenues	241,908	271,336	726,075	742,758
Expenses
Operating expenses, including related party expenses of $6,922 and $20,099 in 2017, and $5,417 and $18,391 in 2016	43,448	43,549	123,938	124,319
Real estate taxes	40,610	38,900	118,232	113,426
Ground rent	5,236	5,266	15,706	15,736
Interest expense, net of interest income	34,627	24,723	96,202	83,367
Amortization of deferred financing costs	2,580	2,081	6,706	5,953
Depreciation and amortization	53,549	57,916	156,106	159,365
Transaction related costs	0	98	2	343
Marketing, general and administrative	92	156	321	605
Total expenses	180,142	172,689	517,213	503,114
Income before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves	61,766	98,647	208,862	239,644
Equity in net income from unconsolidated joint ventures	2,927	4,276	10,362	10,399
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	282	0	285	0
Gain (loss) on sale of real estate	114	0	5,047	(6,899)
Depreciable real estate reserves	(379)	0	(85,707)	0
Net income	64,710	102,923	138,849	243,144
Net loss (income) attributable to noncontrolling interests in other partnerships	1,467	(1,279)	19,587	(3,353)
Preferred units dividend	(955)	(955)	(2,863)	(2,865)
Net income attributable to ROP common unitholder	$ 65,222	$ 100,689	$ 155,573	$ 236,926

Consolidated Statements of Ope5

Consolidated Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Related party expenses included in operating expenses	$ 6,922	$ 20,099	$ 5,417	$ 18,391

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income attributable to ROP common unitholder	$ 65,222	$ 100,689	$ 155,573	$ 236,926
Other comprehensive income:
Change in net unrealized loss/gain on derivative instruments	89	90	269	508
Comprehensive income attributable to ROP common unitholder	$ 65,311	$ 100,779	$ 155,842	$ 237,434

Consolidated Statement of Capit

Consolidated Statement of Capital (Unaudited) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Increase (Decrease) in Partners' Capital
Beginning Balance	$ 5,528,823
Contributions	2,460,274
Distributions	(3,042,168)
Net income	135,986
Other comprehensive income	269
Ending Balance	5,083,184
General Partner's Capital Class A Common Units | Class A Common Units
Increase (Decrease) in Partners' Capital
Beginning Balance	5,139,842
Contributions	2,460,274
Distributions	(2,998,274)
Net income	155,573
Ending Balance	4,757,415
Limited Partner's Capital
Increase (Decrease) in Partners' Capital
Beginning Balance	0
Ending Balance	0
Noncontrolling Interests In Other Partnerships
Increase (Decrease) in Partners' Capital
Beginning Balance	390,599
Distributions	(43,894)
Net income	(19,587)
Ending Balance	327,118
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Partners' Capital
Beginning Balance	(1,618)
Ending Balance	$ (1,349)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities
Net income	$ 138,849	$ 243,144
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	162,812	165,318
Equity in net income from unconsolidated joint ventures	(10,362)	(10,399)
Distributions of cumulative earnings from unconsolidated joint ventures	12,032	7,286
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	(285)	0
(Gain) loss on sale of real estate	(5,047)	6,899
Depreciable real estate reserves	85,707	0
Deferred rents receivable	(9,063)	(15,992)
Other non-cash adjustments	(33,917)	(38,249)
Changes in operating assets and liabilities:
Restricted cash—operations	1,156	(10,365)
Tenant and other receivables	(625)	2
Deferred lease costs	(9,589)	(22,447)
Other assets	(51,792)	(26,934)
Accounts payable, accrued expenses and other liabilities	(2,460)	(4,736)
Deferred revenue and land leases payable	9,356	9,956
Net cash provided by operating activities	286,772	303,483
Investing Activities
Additions to land, buildings and improvements	(97,712)	(82,895)
Escrowed cash—capital improvements/acquisition deposits/deferred purchase price	5,500	368
Investments in unconsolidated joint ventures	(84)	(24,961)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	49,038	1,028
Net proceeds from disposition of real estate/joint venture interest	113,585	42,316
Other investments	57,785	16,066
Origination of debt and preferred equity investments	(935,724)	(555,089)
Repayments or redemption of debt and preferred equity investments	677,676	667,251
Net cash (used in) provided by investing activities	(129,936)	64,084
Financing Activities
Proceeds from mortgages and other loans payable	250,000	383
Repayments of mortgages and other loans payable	0	(119,165)
Proceeds from revolving credit facility and senior unsecured notes	1,447,800	1,260,300
Repayments of revolving credit facility and senior unsecured notes	(1,167,800)	(2,259,608)
Distributions to noncontrolling interests in other partnerships	(43,894)	(643)
Contributions from common unitholder	2,321,970	4,137,727
Distributions to common and preferred unitholders	(3,001,084)	(3,425,243)
Other obligations related to loan participations	16,737	59,150
Deferred loan costs and capitalized lease obligation	(4,481)	(4,298)
Net cash used in financing activities	(180,752)	(351,397)
Net (decrease) increase in cash and cash equivalents	(23,916)	16,170
Cash and cash equivalents at beginning of period	59,930	50,026
Cash and cash equivalents at end of period	36,014	66,196
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Tenant improvements and capital expenditures payable	6,447	8,973
Deferred leasing payable	477	2,949
Change in fair value of hedge	2	208
Transfer to assets held for sale	273,455	0
Transfer to liabilities related to assets held for sale	1,290	0
Exchange of debt investment for equity in joint venture	0	68,581
Removal of fully depreciated commercial real estate properties	3,955	8,516
Contributions from Common Unitholder	138,304	0
Deconsolidation of a subsidiary	3,520	0
Proceeds from sale held in restricted cash	38,166	0
Settlement of Related Party Receivable with SL Green common stock	0	90,000
Issuance of related party payable for SL Green common stock	$ 0	$ 23,808

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Reckson Operating Partnership, L.P., or ROP, commenced operations on June 2, 1995. The sole general partner of ROP is Wyoming Acquisition GP LLC., or WAGP, a wholly-owned subsidiary of SL Green Operating Partnership, L.P., or the Operating Partnership. The sole limited partner of ROP is the Operating Partnership. The Operating Partnership is 95.55% owned by SL Green Realty Corp., or SL Green, as of September 30, 2017 . SL Green is a self-administered and self-managed real estate investment trust, and is the sole managing general partner of the Operating Partnership. Unless the context requires otherwise, all references to "we," "our," "us" and the "Company" means ROP and all entities owned or controlled by ROP. ROP is engaged in the acquisition, ownership, management and operation of commercial and residential real estate properties, principally office properties, and also owns land for future development, located in New York City, Westchester County, Connecticut and New Jersey, which collectively is also known as the New York Metropolitan area. As of September 30, 2017 , 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, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties: Location Type Number of Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office 16 8,463,245 95.7 % Retail (2)(3) 5 364,816 98.0 % Fee Interest 1 176,530 100.0 % 22 9,004,591 95.9 % Suburban Office (4) 15 2,746,000 84.6 % Retail 1 52,000 100.0 % 16 2,798,000 84.9 % Total commercial properties 38 11,802,591 93.2 % Residential: Manhattan Residential (2) — 222,855 88.0 % Total portfolio 38 12,025,446 93.2 % (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 September 30, 2017 , we owned a building at 315 West 33rd Street, also known as The Olivia, 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 this 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. (3) Includes two unconsolidated joint venture retail properties at 131-137 Spring Street comprised of approximately 68,342 square feet. (4) Includes the properties at 16 Court Street in Brooklyn, New York, and 125 Chubb Avenue in Lyndhurst, New Jersey which are classified as held for sale at September 30, 2017. The sales closed in October 2017. As of September 30, 2017 , we held debt and preferred equity investments with a book value of $2.2 billion , including $0.1 billion of debt and preferred equity investments and other financing receivables that are included in other balance sheet line items other than the Debt and Preferred Equity Investments line item. Basis of Quarterly Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of the financial position of the Company at September 30, 2017 and the results of operations for the periods presented have been included. The operating results for the period presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 . These financial statements should be read in conjunction with the financial statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2016 . The consolidated balance sheet at December 31, 2016 has been derived from the audited financial statements as of that date but do not include all the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
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. Investment in Commercial Real Estate Properties 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 September 30, 2017 . We recorded $0.4 million depreciable real estate reserves for the three months ended September 30, 2017 , and aggregate depreciable real estate reserves of $85.7 million for the nine months ended September 30, 2017 . See Note 4, "Property Dispositions". 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. We recognized $4.3 million and $12.7 million of rental revenue for the three and nine months ended September 30, 2017 , and $8.1 million and $15.9 million of rental revenue for the three and nine months ended September 30, 2016 , 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. The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Identified intangible assets (included in other assets): Gross amount $ 285,271 $ 311,830 Accumulated amortization (241,949 ) (253,064 ) Net (1) $ 43,322 $ 58,766 Identified intangible liabilities (included in deferred revenue): Gross amount $ 508,373 $ 524,793 Accumulated amortization (372,190 ) (368,738 ) Net (1) $ 136,183 $ 156,055 (1) As of September 30, 2017 and December 31, 2016, $3.9 million and none , respectively and $1.1 million and none , respectively, of net intangible assets and net intangible liabilities, were reclassified to assets held for sale and liabilities related to assets held for sale. Fair Value Measurements See Note 12, "Fair Value Measurements." 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 September 30, 2017 . 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 the three and nine months ended September 30, 2017 and 2016 . Income Taxes ROP is a disregarded entity of SL Green Operating Partnership, L.P. for federal income tax purposes, and, as a result, all income and losses of ROP are considered income and losses of SL Green Operating Partnership, L. P. No provision has been made for income taxes in the consolidated financial statements since such taxes, if any, are the responsibility of the individual partners of SL Green Operating Partnership, L.P. Shares Contributed by Parent Company We present shares of SL Green common stock as a contra-equity account in our financial statements. 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 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 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, Westchester County, Connecticut and New Jersey. The tenants located in our buildings operate in various industries. No tenant in our portfolio accounted for more than 5.0% of our share of annualized cash rent, including our share of joint venture annualized rent, at September 30, 2017 . For the three months ended September 30, 2017 , 13.8% , 9.1% , 7.4% , 7.2% , 7.1% , 6.3% , 6.1% , and 5.9% of our share of cash rent, including our share of joint venture annualized rent was attributable to 1185 Avenue of the Americas, 625 Madison Avenue, 919 Third Avenue, 750 Third Avenue, 810 Seventh Avenue, 555 West 57th Street, 125 Park Avenue. and 1350 Avenue of the Americas, respectively. Our share of annualized cash rent for all other properties was below 5.0% . Reclassification Certain prior year balances have been reclassified to conform to our current year presentation. Accounting Standards Updates In August 2017, the FASB issued Accounting Standards Update (ASU) No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities. The amendments in the new standard will permit more flexibility in hedging interest rate risk for both variable rate and fixed rate financial instruments. The standard will also enhance the presentation of hedge results in the financial statements. The guidance is effective for fiscal years beginning after December 15, 2018 and early adoption is permitted. The Company has not yet adopted the guidance, and does not expect a material impact on the Company’s consolidated financial statements when the new standard is implemented. In February 2017, the FASB issued Accounting Standards Update (ASU) No. 2017-05 to clarify the scope of Subtopic 610-20 as well as provide guidance on accounting for partial sales of nonfinancial assets. Subtopic 610-20 was issued in May 2014 as part of ASU 2014-09. The Company anticipates adopting this guidance January 1, 2018, and applying the modified retrospective approach. The Company is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In January, 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The guidance clarifies the definition of a business and provides guidance to assist with determining whether transactions should be accounted for as acquisitions of assets or businesses. The main provision is that an acquiree is not a business if substantially all of the fair value of the gross assets is concentrated in a single identifiable asset or group of assets. The Company adopted the guidance on the issuance date effective January 5, 2017. The Company expects that most of our real estate acquisitions will be considered asset acquisitions under the new guidance and that transaction costs will be capitalized to the investment basis which is then subject to a purchase price allocation based on relative fair value. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The guidance will require entities to show the changes on the total cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between these items on the statement of cash flows. The guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The ASU provides final guidance on eight cash flow issues, including debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, distributions received from equity method investees, separately identifiable cash flows and application of the predominance principle, and others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted the guidance effective January 1, 2017 and there was no impact on the Company’s consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The guidance changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The guidance replaces the current ‘incurred loss’ model with an ‘expected loss’ approach. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted after December 2018. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, Investments Equity Method and Joint Ventures (Topic 323). The guidance eliminates the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. The Company adopted the guidance effective January 1, 2017 and there was no impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases. The guidance requires lessees to recognize lease assets and lease liabilities for those leases classified as operating leases under the previous standard. Depending on the lease classification, lessees will recognize expense based on the effective interest method for finance leases or on a straight-line basis for operating leases. The accounting applied by a lessor is largely unchanged from that applied under the previous standard. One of the impacts on the Company will be the presentation and disclosure in the financial statements of non-lease components such as charges to tenants for a building’s operating expenses. The non-lease components will be presented separately from the lease components in both the Consolidated Statements of Operations and Consolidated Balance Sheets. Another impact is the measurement and presentation of ground leases under which the Company is lessee. The Company is required to record a liability for the obligation to make payments under the lease and an asset for the right to use the underlying asset during the lease term and will also apply the new expense recognition requirements given the lease classification. The Company is currently quantifying these impacts. The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company anticipates adopting this guidance January 1, 2019 and will apply the modified retrospective approach. In January 2016, the FASB issued ASU 2016-01 (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to record changes in instruments-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. The guidance is effective for fiscal years beginning after December 15, 2017, and for interim periods therein. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In May 2014, the FASB issued a new comprehensive revenue recognition guidance which requires us to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods and services (ASU 2014-09). The FASB also issued implementation guidance in March 2016, April 2016 and May 2016 - ASU’s 2016-08, 2016-10 and 2016-12, respectively. These ASUs are effective for annual and interim periods beginning after December 15, 2017. The Company will adopt this guidance January 1, 2018. Since the Company’s revenue is related to leasing activities, the adoption of this guidance will not have a material impact on the consolidated financial statements. The new guidance is applicable to service contracts with joint ventures for which the Company earns property management fees, leasing commissions and development and construction fees. The adoption of this new guidance does not change the accounting for these fees as the pattern of recognition of revenue does not change with the new guidance. We will continue to recognize revenue over time on these contracts because the customer simultaneously receives and consumes the benefits provided by our performance. Thus, the analysis of our contracts under the new revenue recognition standard is consistent with our current revenue recognition model.

Property Acquisitions

Property Acquisitions	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions During the nine months ended September 30, 2017 , we did not acquire any properties from a third party.

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Property Dispositions	Properties Held for Sale and Property Dispositions Properties Held for Sale During the three months ended September 30, 2017 , we entered into an agreement to sell the property at 16 Court Street in Brooklyn, New York, for a gross sales price of $171.0 million . As of September 30, 2017, 16 Court Street in Brooklyn, New York and 125 Chubb in Lyndhurst, New Jersey were held for sale. We closed on the sale of both properties in October 2017. Property Dispositions The following table summarizes the properties sold during the nine months ended September 30, 2017 : Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain (loss) (2) (in millions) 520 White Plains Road April 2017 Office 180,000 $ 21.0 $ (14.6 ) 102 Greene Street (3) April 2017 Retail 9,200 43.5 4.9 680-750 Washington Boulevard July 2017 Office 325,000 97.0 (44.2 ) (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 102 Greene Street is net of $0.9 million in employee compensation awards accrued in connection with the realization of the investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, gain on sale amounts do not include adjustments for expenses recorded in subsequent periods. (3) In April 2017, we closed on the sale of a 90% interest in 102 Greene Street and had subsequently accounted for our interest in the property as an investment in unconsolidated joint ventures. We sold the remaining 10% interest in September 2017. See Note 6, "Investments in Unconsolidated Joint Ventures".

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments Below is the rollforward analysis of the activity relating to our debt and preferred equity investments as of September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Balance at beginning of period (1) $ 1,640,412 $ 1,670,020 Debt Investment Originations/Accretion (2) 944,494 1,009,176 Preferred Equity Investment Originations/Accretion (2) 144,013 5,698 Redemptions/Sales/Syndications/Amortization (3) (708,180 ) (1,044,482 ) Balance at end of period (1) $ 2,020,739 $ 1,640,412 (1) Net of unamortized fees, discounts, and premiums. (2) Accretion includes amortization of fees and discounts and paid-in-kind investment income. (3) Certain participations in debt investments that were sold or syndicated did not meet the conditions for sale accounting are included in other assets and other liabilities on the consolidated balance sheets. Debt Investments As of September 30, 2017 and December 31, 2016 , we held the following debt investments with an aggregate weighted average current yield of 9.49% , excluding our investment in Two Herald Square, at September 30, 2017 (in thousands): Loan Type September 30, 2017 Future Funding Obligations September 30, 2017 Senior September 30, 2017 (1) December 31, 2016 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Mortgage/Jr. Mortgage Loan (3) $ — $ — $ 250,164 $ — April 2017 Mortgage Loan (4) — — 26,352 26,311 February 2019 Mortgage Loan — — 275 380 August 2019 Mezzanine Loan (5a) — 1,160,000 201,757 — March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,909 — April 2022 Mezzanine Loan — 87,595 12,697 12,692 November 2023 Mezzanine Loan (5b) — 115,000 12,930 12,925 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 15,000 15,000 November 2026 Mezzanine Loan — 1,657,500 55,250 — June 2027 Mezzanine Loan (6) — — — 66,129 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 193,422 Total fixed rate $ — $ 3,617,095 $ 632,834 $ 360,359 Floating Rate Investments: Mortgage/Mezzanine Loan (8) 622 — 23,372 20,423 October 2017 Mezzanine Loan (5c) — 85,000 15,340 15,141 December 2017 Mezzanine Loan (5d) — 65,000 14,832 14,656 December 2017 Mezzanine Loan (5e) 795 — 15,132 15,051 December 2017 Mortgage/Mezzanine Loan (9) — 125,000 29,966 29,998 January 2018 Mezzanine Loan — 40,000 19,964 19,913 April 2018 Jr. Mortgage Participation — 117,808 34,899 34,844 April 2018 Mezzanine Loan 523 20,523 10,916 10,863 August 2018 Mortgage/Mezzanine Loan — — 19,914 19,840 August 2018 Mortgage Loan — 65,000 14,935 14,880 August 2018 Loan Type September 30, 2017 Future Funding Obligations September 30, 2017 Senior September 30, 2017 (1) December 31, 2016 Carrying Value (1) Maturity Date (2) Mortgage/Mezzanine Loan (10) — — 16,957 16,960 September 2018 Mezzanine Loan — 37,500 14,801 14,648 September 2018 Mezzanine Loan 2,325 45,025 34,782 34,502 October 2018 Mezzanine Loan — 335,000 74,683 74,476 November 2018 Mezzanine Loan — 33,000 26,907 26,850 December 2018 Mezzanine Loan 1,050 171,939 58,598 56,114 December 2018 Mezzanine Loan 8,267 289,621 71,067 63,137 December 2018 Mezzanine Loan 5,197 229,084 74,314 64,505 December 2018 Mezzanine Loan — 45,000 12,156 12,104 January 2019 Mortgage/Mezzanine Loan (5f) 30,101 — 158,757 — January 2019 Mezzanine Loan 6,081 24,086 7,812 5,410 January 2019 Mezzanine Loan — 38,000 21,927 21,891 March 2019 Mezzanine Loan 279 173,700 36,936 — April 2019 Mezzanine Loan — 265,000 24,798 24,707 April 2019 Mortgage/Jr. Mortgage Participation Loan 29,661 194,094 69,705 65,554 August 2019 Mezzanine Loan 2,034 187,500 37,835 37,322 September 2019 Mortgage/Mezzanine Loan 49,933 — 130,350 111,819 September 2019 Mortgage/Mezzanine Loan 30,494 — 38,934 33,682 January 2020 Mezzanine Loan (11) 6,794 537,748 72,597 125,911 January 2020 Mezzanine Loan 7,164 33,587 10,988 — July 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,627 15,606 July 2021 Mezzanine Loan — 280,000 34,124 — August 2022 Mezzanine Loan (12) — — — 15,369 Mortgage/ Mezzanine Loan (6) — — — 32,847 Mortgage/Mezzanine Loan (6) — — — 22,959 Mezzanine Loan (13) — — — 14,957 Mortgage/Mezzanine Loan (14) — — — 145,239 Total floating rate $ 181,320 $ 3,498,215 $ 1,243,925 $ 1,232,178 Total $ 181,320 $ 7,115,310 $ 1,876,759 $ 1,592,537 (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) These loans were purchased at par in April and May 2017 and were in maturity default at the time of acquisition. At the time the loans were purchased, the Company expected to collect all contractually required payments, including interest. In August 2017, the Company determined that it was probable that the loans would not be repaid in full and therefore, the loans were put on non-accrual status. No impairment was recorded as the Company believes that the fair value of the property exceeds the carrying amount of the loans. The loans had an outstanding balance including accrued interest of $259.3 million at the time that they were put on non-accrual status. (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, is currently on non-accrual status and has no carrying value. (5) Carrying value is net of the following amounts that were sold or syndicated, which are included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting: (a) $1.2 million , (b) $12.0 million , (c) $14.6 million , (d) $14.1 million , (e) $5.1 million , and (f) $21.2 million (6) This loan was repaid in June 2017. (7) This loan was repaid in March 2017. (8) This loan was extended in October 2017. (9) This loan was extended in January 2017. (10) This loan was extended in September 2017. (11) $66.1 million of outstanding principal was syndicated in February 2017. (12) This loan was repaid in September 2017. (13) This loan was contributed to a joint venture in May 2017. (14) This loan was repaid in January 2017. Preferred Equity Investments As of September 30, 2017 and December 31, 2016 , we held the following preferred equity investments with an aggregate weighted average current yield of 6.98% at September 30, 2017 (in thousands): Type September 30, 2017 September 30, 2017 September 30, 2017 (1) December 31, 2016 (1) Mandatory Redemption (2) Preferred Equity (3) $ — $ 272,000 $ 143,980 $ — April 2021 Preferred Equity (4) — — — 9,982 Preferred Equity (5) — — — 37,893 Total $ — $ 272,000 $ 143,980 $ 47,875 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) In February 2016, we closed on the sale of 885 Third Avenue and retained a preferred equity position in the property. The sale 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 remained on our consolidated balance sheet until the criteria was met in April 2017 at which time the property was deconsolidated and the preferred equity investment was recognized. (4) This investment was redeemed in May 2017. (5) This investment was redeemed in April 2017. At September 30, 2017 and December 31, 2016 , all debt and preferred equity investments were performing in accordance with the terms of the relevant investments, with the exception of a mortgage and junior mortgage participation purchased in maturity default in May 2017 and April 2017 discussed in subnote 3 of the Debt Investments table above and a junior mortgage participation acquired in September 2014, which was acquired for zero and has a carrying value of zero , as further discussed in subnote 4 of the Debt Investments table above. We have determined that we have one portfolio segment of financing receivables at September 30, 2017 and 2016 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 $94.8 million and $144.5 million at September 30, 2017 and December 31, 2016 , respectively. No financing receivables were 90 days past due at September 30, 2017 .

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 , none of our investments in unconsolidated joint ventures are VIEs. The table below provides general information on each of our joint ventures as of September 30, 2017 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 $ 277,750 Mezzanine Loan (3) Private Investors 33.33% 33.33% — May 2017 15,000 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of September 30, 2017 . Changes in ownership or economic interests, if any, 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 May 2017, the Company contributed a mezzanine loan secured by a commercial property in midtown Manhattan to a joint venture and retained a 33.33% interest in the venture. The carrying value is net of $10.0 million that was sold, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting. In October 2017, the initial maturity date of November 2017 was extended to November 2018. 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 September 30, 2017 and December 31, 2016 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type September 30, 2017 December 31, 2016 Maturity Date Mezzanine Loan and Preferred Equity (1) $ 100,000 $ 100,000 March 2018 Mezzanine Loan (2) 25,854 24,542 July 2036 $ 125,854 $ 124,542 (1) These loans were extended in February 2017. (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 nine months ended September 30, 2017 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain on Sale (in thousands) (2) 102 Greene Street 10.00% September 2017 Ownership Interest $ 43,500 $ 283 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. In May 2017, our investment in a joint venture that owned two mezzanine notes secured by interests in the entity that owns 76 11th Avenue was repaid after the joint venture received repayment of the underlying loans. Joint Venture Mortgages and Other Loans Payable We generally finance our joint ventures with non-recourse debt. In certain cases we may provide 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 September 30, 2017 and December 31, 2016 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) September 30, 2017 December 31, 2016 Floating Rate Debt: 131-137 Spring Street 20.00 % August 2020 2.77 % $ 141,000 $ 141,000 Total joint venture mortgages and other loans payable $ 141,000 $ 141,000 Deferred financing costs, net (3,139 ) (3,970 ) Total joint venture mortgages and other loans payable, net $ 137,861 $ 137,030 (1) Economic interest represent the Company's interests in the joint venture as of September 30, 2017 . Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures note above. (2) Effective weighted average interest rate for the three months ended September 30, 2017 , taking into account interest rate hedges in effect during the period. The combined balance sheets for the unconsolidated joint ventures, at September 30, 2017 and December 31, 2016 are as follows (in thousands): September 30, 2017 December 31, 2016 Assets Commercial real estate property, net $ 274,695 $ 279,451 Debt and preferred equity investments, net 140,850 273,749 Other assets 15,019 18,922 Total assets $ 430,564 $ 572,122 Liabilities and members' equity Mortgages and other loans payable, net $ 137,861 $ 137,030 Other liabilities 19,764 22,185 Members' equity 272,939 412,907 Total liabilities and members' equity $ 430,564 $ 572,122 Company's investments in unconsolidated joint ventures $ 128,794 $ 174,127 The combined statements of operations for the unconsolidated joint ventures for the three and nine months ended September 30, 2017 and 2016 , are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Total revenues $ 7,340 $ 3,707 $ 26,934 $ 27,590 Operating expenses 182 (175 ) 636 1,003 Real estate taxes 381 33 1,013 881 Interest expense, net of interest income 1,025 37 2,759 2,144 Amortization of deferred financing costs 283 — 837 831 Depreciation and amortization 2,102 — 6,304 6,303 Total expenses $ 3,973 $ (105 ) $ 11,549 $ 11,162 Net income $ 3,367 $ 3,812 $ 15,385 $ 16,428 Company's equity in net income from unconsolidated joint ventures $ 2,927 $ 4,276 $ 10,362 $ 10,399

Mortgages and Other Loans Payab

Mortgages and Other Loans Payable	9 Months Ended
	Sep. 30, 2017
Mortgage Note 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 or debt investments at September 30, 2017 and December 31, 2016 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2017 December 31, 2016 Fixed Rate Debt: 919 Third Avenue (2) June 2023 5.12 % $ 500,000 $ 500,000 315 West 33rd Street February 2027 4.24 % 250,000 — Floating Rate Debt: 2016 Master Repurchase Agreement July 2018 3.73 % $ 184,642 $ 184,642 Total mortgages and other loans payable $ 934,642 $ 684,642 Deferred financing costs, net of amortization (12,593 ) (8,574 ) Total mortgages and other loans payable, net $ 922,049 $ 676,068 (1) Effective weighted average interest rate for the quarter ended September 30, 2017 . (2) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan. At September 30, 2017 and December 31, 2016 , 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 $2.5 billion and $1.7 billion , respectively. Master Repurchase Agreements The Company has entered into two Master Repurchase Agreements, or MRAs, known as the 2016 MRA and 2017 MRA, which provide us with the ability to sell certain debt investments with a simultaneous agreement to repurchase the same at a certain date or on demand. 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 facilities 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 our access to additional liquidity through the 2012 credit facility, as defined below. In June 2017, we entered into the 2017 MRA, with a maximum facility capacity of $300.0 million . The facility bears interest on a floating rate basis at a spread to 30-day LIBOR based on the pledged collateral and advance rate and has an initial one year term, with two one year extension options. At September 30, 2017 , the facility had a carrying value of $(1.1) million , representing deferred financing costs presented within other liabilities. In July 2016, we entered into a restated 2016 MRA, with a maximum facility capacity of $300.0 million. The facility bears interest ranging from 225 and 400 basis points over 30-day LIBOR depending on the pledged collateral and has an initial two -year term, with a one year extension option. 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 when the average daily balance is less than $150.0 million . At September 30, 2017 , the facility had a carrying value of $182.8 million , net of deferred financing costs.

Corporate Indebtedness

Corporate Indebtedness	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 , 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 September 30, 2017 , 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 September 30, 2017 , the applicable spread was 125 basis points for the revolving credit facility and 140 basis points for the term loan facility. At September 30, 2017 , the effective interest rate was 2.49% for the revolving credit facility and 2.63% 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 September 30, 2017 , the facility fee was 25 basis points. As of September 30, 2017 , we had $80.8 million of outstanding letters of credit, $280.0 million drawn under the revolving credit facility and $1.2 billion outstanding under the term loan facility, with total undrawn capacity of $1.2 billion under the 2012 credit facility. At September 30, 2017 and December 31, 2016 , the revolving credit facility had a carrying value of $275.8 million and $(6.3) million , respectively, net of deferred financing costs. The December 31, 2016 carrying value represents deferred financing costs and is presented within other liabilities. At September 30, 2017 and December 31, 2016 , the term loan facility had a carrying value of $1.2 billion and $1.2 billion , respectively, net of deferred financing costs. ROP, SL Green, and the Operating Partnership are all borrowers jointly and severally obligated under the 2012 credit facility. None of SL Green's 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 September 30, 2017 and December 31, 2016 , respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, Coupon (1) Effective Initial Maturity Date August 5, 2011 (2) $ 250,000 $ 249,934 $ 249,880 5.00 % 5.00 % 7 August 2018 March 16, 2010 (2) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (2) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (2) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 $ 800,000 $ 799,934 $ 799,880 Deferred financing costs, net (3,650 ) (4,620 ) $ 800,000 $ 796,284 $ 795,260 (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 SL Green, the Operating Partnership and ROP, as co-obligors. In October 2017, SL Green, the Operating Partnership and ROP, as co-obligors issued an additional $100.0 million of the 4.50% senior unsecured bonds due December 2022. The additional notes priced at 105.334% plus accrued interest from June 1, 2017, with a yield to maturity of 3.298% . ROP provides a guaranty of the Operating Partnership's obligations under its 3.00% Exchangeable Senior Notes due 2017, which were repaid in October 2017. ROP also provides a guaranty of the Operating Partnership's obligations under its 3.25% Senior Notes due 2022, which were issued in October 2017 and will mature in October 2022. 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, SL Green's 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 SL Green will not during any time when a default is continuing, make distributions with respect to SL Green's common stock or other equity interests, except to enable SL Green to continue to qualify as a REIT for Federal income tax purposes. As of September 30, 2017 and 2016 , we were in compliance with all such covenants. Principal Maturities Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility and senior unsecured notes as of September 30, 2017 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Revolving Unsecured Term Loan Senior Unsecured Notes Total Remaining 2017 $ — $ — $ — $ — $ — $ — 2018 — 184,642 — — 250,000 434,642 2019 — — 280,000 1,183,000 — 1,463,000 2020 — — — — 250,000 250,000 2021 — — — — — — Thereafter — 750,000 — — 300,000 1,050,000 $ — $ 934,642 $ 280,000 $ 1,183,000 $ 800,000 $ 3,197,642 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Interest expense before capitalized interest $ 34,658 $ 25,087 $ 96,740 $ 84,175 Interest capitalized (31 ) (362 ) (533 ) (799 ) Interest income — (2 ) (5 ) (9 ) Interest expense, net $ 34,627 $ 24,723 $ 96,202 $ 83,367

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2017
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 $0.8 million and $2.5 million for the three and nine months ended September 30, 2017 and 2016, respectively. We also recorded expenses for these services, inclusive of capitalized expenses, of $2.6 million and and $7.1 million for the three and nine months ended September 30, 2017 , respectively, for these services (excluding services provided directly to tenants), and $1.2 million and $6.0 million for the three and nine months ended September 30, 2016 , respectively. Allocated Expenses from SL Green Property operating expenses include an allocation of salary and other operating costs from SL Green based on square footage of the related properties. Such amount was approximately $3.0 million and $9.2 million for the three and nine months ended September 30, 2017 , respectively. The amount was $2.8 million and $8.2 million for the three and nine months ended September 30, 2016 , respectively. Insurance We obtained insurance coverage through an insurance program administered by SL Green. In connection with this program, we incurred insurance expense of approximately $1.3 million and $4.1 million for the three and nine months ended September 30, 2017 . We incurred insurance expense of approximately $1.5 million and $4.4 million for the three and nine months ended September 30, 2016 .

Preferred Units

Preferred Units	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Preferred Units	Preferred Units Through a consolidated subsidiary, we have authorized up to 109,161 3.50% Series A Preferred Units of limited partnership interest, or the Greene Series A Preferred Units, with a liquidation preference of $1,000.00 per unit. In August 2015, the Company issued 109,161 Greene Series A Preferred Units in conjunction with an acquisition. The Greene 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 Greene 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 Greene Series B Preferred Units. The Greene 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 SL Green common stock for each Greene Series B Preferred Unit. As of September 30, 2017 , no Greene Series B Preferred Units have been issued. ASC 815 Derivatives and Hedging requires bifurcation of certain embedded derivative instruments, such as conversion features in convertible equity instruments, and their measurement at fair value for accounting purposes. The conversion feature embedded in the Subsidiary Series A Preferred Units was evaluated, and it was determined that the conversion feature should be bifurcated from its host instrument and accounted for as a freestanding derivative. The derivative is reported as a derivative liability in accrued interest and other liabilities on the accompanying consolidated balance sheet and is adjusted to its fair value at each reporting date, with a corresponding adjustment to interest expense, net of interest income. The embedded derivative for the Subsidiary Series A Preferred Units was initially recorded at a fair value of zero on July 22, 2015, the date of issuance. At December 31, 2016, the carrying amount of the derivative was adjusted to its fair value of zero , with a corresponding adjustment to preferred units and interest expense, net of interest income. At September 30, 2017 , the carrying amount and fair value of the derivative remained at zero .

Partners' Capital

Partners' Capital	9 Months Ended
	Sep. 30, 2017
Partners' Capital Notes [Abstract]
Partners' Capital	Partners' Capital Since consummation of the Merger on January 25, 2007, the Operating Partnership has owned all the economic interests in ROP either by direct ownership or by indirect ownership through our general partner, which is its wholly-owned subsidiary. Intercompany transactions between SL Green and ROP are generally recorded as contributions and distributions.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2017
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. We determine other than temporary impairment in real estate investments and debt and preferred equity investments, including intangibles primarily utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, as well as sales comparison approach, which utilizes comparable sales, listings and sales contracts. All of which are classified as Level 3 inputs. As of September 30, 2017 we held notes receivable totaling $250.0 million which were purchased at par, and were in maturity default at the time of acquisition. In August 2017, the Company determined that it was probable that the loans would not be repaid in full and therefore, the loans were put on non-accrual status. The Company has initiated proceedings to foreclose on the property, and expects to take control of the property unless the buyer is able to repay the principal and interest, including default interest and fees, on the notes receivable in full prior to the completion of the foreclosure process. We believe the collateral value is sufficient to recover the carrying amounts of the notes receivable. 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 instrument 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 September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 2,020,739 (2) $ 1,640,412 (2) Fixed rate debt $ 2,349,934 $ 2,441,240 $ 2,099,880 $ 2,183,042 Variable rate debt 847,642 855,640 567,642 580,083 $ 3,197,576 $ 3,296,880 $ 2,667,522 $ 2,763,125 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2017 , debt and preferred equity investments had an estimated fair value ranging between $2.0 billion and $2.2 billion . At December 31, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.6 billion and $1.8 billion . Disclosure about fair value of financial instruments was based on pertinent information available to us as of September 30, 2017 and December 31, 2016 . 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	9 Months Ended
	Sep. 30, 2017
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. As of September 30, 2017 , the Company had not designated any interest rate swap agreements on any debt investment. Gains and losses on terminated hedges are included in accumulated other comprehensive loss, and are recognized into earnings over the term of the related senior unsecured notes. As of September 30, 2017 and December 31, 2016 , the deferred net losses from these terminated hedges, which are included in accumulated other comprehensive loss relating to net unrealized loss on derivative instruments, was approximately $1.3 million and $1.6 million , respectively. 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 $0.4 million of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense within the next 12 months. The following table presents the effect of our derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the three months ended September 30, 2017 and 2016 , respectively (in thousands): Amount of (Loss) 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 Gain Recognized in Income on Derivative Amount of Gain Recognized into Income (Ineffective Portion) Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Derivative 2017 2016 2017 2016 2017 2016 Interest Rate Swap $ — $ — Interest expense $ 89 $ 90 Interest expense $ — $ — The following table presents the effect of our derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the nine months ended September 30, 2017 and 2016 , respectively (in thousands): Amount of (Loss) Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of Gain Recognized in Income on Derivative Amount of Gain Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2017 2016 2017 2016 2017 2016 Interest Rate Swap $ — $ (13 ) Interest expense $ 269 $ 521 Interest expense $ — $ 3

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of September 30, 2017 , we 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. Guarantees During the year ended December 31, 2015 , Belmont Insurance Company, or Belmont, a New York licensed captive insurance company and an affiliate of SL Green, became a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Belmont could borrow funds from the FHLBNY in the form of secured advances. As of December 31, 2016 , certain commercial real estate properties and debt and preferred equity investments of the Company were pledged as collateral to secure advances under the FHLBNY facility. In January 2017, all funds borrowed from the FHLBNY were repaid and Belmont's membership was terminated in February 2017. 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. Ground Leases Arrangements The following is a schedule of future minimum lease payments under non-cancellable operating leases with initial terms in excess of one year as of September 30, 2017 (in thousands): Non-cancellable operating leases Remaining 2017 $ 5,147 2018 20,586 2019 20,586 2020 20,586 2021 20,736 Thereafter 308,202 Total minimum lease payments $ 395,843

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information We are engaged in acquiring, owning, managing and leasing commercial properties in Manhattan, Brooklyn, Westchester County, Connecticut and New Jersey and have two reportable segments, real estate and debt and preferred equity investments. 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, insurance, 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 consolidated results of operations for the three and nine months ended September 30, 2017 and 2016 , and selected asset information as of September 30, 2017 and December 31, 2016 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Three months ended: September 30, 2017 $ 193,962 $ 47,946 $ 241,908 September 30, 2016 195,621 75,715 271,336 Nine months ended: September 30, 2017 $ 577,151 $ 148,924 $ 726,075 September 30, 2016 567,277 175,481 742,758 Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves Three months ended: September 30, 2017 $ 24,705 $ 39,988 $ 64,693 September 30, 2016 27,975 74,948 102,923 Nine months ended: September 30, 2017 $ 87,700 $ 131,524 $ 219,224 September 30, 2016 82,430 167,613 250,043 Total assets Real Estate Segment Debt and Preferred Equity Segment Total Company As of: September 30, 2017 $ 6,563,972 $ 2,189,588 $ 8,753,560 December 31, 2016 6,785,305 1,969,308 8,754,613 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 borrowings on the 2016 MRA and 2017 MRA. Interest is imputed on the investments that do not collateralize the 2016 MRA or 2017 MRA 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 three and nine months ended September 30, 2017 , and 2016 , marketing, general and administrative expenses totaled $0.1 million , $0.2 million , $0.3 million , and $0.6 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 three and nine months ended September 30, 2017 and 2016 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves $ 64,693 $ 102,923 $ 219,224 $ 250,043 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 282 — 285 — Gain (loss) on sale of real estate 114 — 5,047 (6,899 ) Depreciable real estate reserves (379 ) — (85,707 ) — Net income $ 64,710 $ 102,923 $ 138,849 $ 243,144

Significant Accounting Polici24

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
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.
Investment in Commercial Real Estate Properties	Investment in Commercial Real Estate Properties 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 September 30, 2017 . We recorded $0.4 million depreciable real estate reserves for the three months ended September 30, 2017 , and aggregate depreciable real estate reserves of $85.7 million for the nine months ended September 30, 2017 . See Note 4, "Property Dispositions". 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.
Investments in Unconsolidated Joint Ventures	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.
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.
Income Taxes	Income Taxes ROP is a disregarded entity of SL Green Operating Partnership, L.P. for federal income tax purposes, and, as a result, all income and losses of ROP are considered income and losses of SL Green Operating Partnership, L. P. No provision has been made for income taxes in the consolidated financial statements since such taxes, if any, are the responsibility of the individual partners of SL Green Operating Partnership, L.P.
Shares Contributed by Parent Company	Shares Contributed by Parent Company We present shares of SL Green common stock as a contra-equity account in our financial statements.
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 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, 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	Accounting Standards Updates In August 2017, the FASB issued Accounting Standards Update (ASU) No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities. The amendments in the new standard will permit more flexibility in hedging interest rate risk for both variable rate and fixed rate financial instruments. The standard will also enhance the presentation of hedge results in the financial statements. The guidance is effective for fiscal years beginning after December 15, 2018 and early adoption is permitted. The Company has not yet adopted the guidance, and does not expect a material impact on the Company’s consolidated financial statements when the new standard is implemented. In February 2017, the FASB issued Accounting Standards Update (ASU) No. 2017-05 to clarify the scope of Subtopic 610-20 as well as provide guidance on accounting for partial sales of nonfinancial assets. Subtopic 610-20 was issued in May 2014 as part of ASU 2014-09. The Company anticipates adopting this guidance January 1, 2018, and applying the modified retrospective approach. The Company is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In January, 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business. The guidance clarifies the definition of a business and provides guidance to assist with determining whether transactions should be accounted for as acquisitions of assets or businesses. The main provision is that an acquiree is not a business if substantially all of the fair value of the gross assets is concentrated in a single identifiable asset or group of assets. The Company adopted the guidance on the issuance date effective January 5, 2017. The Company expects that most of our real estate acquisitions will be considered asset acquisitions under the new guidance and that transaction costs will be capitalized to the investment basis which is then subject to a purchase price allocation based on relative fair value. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The guidance will require entities to show the changes on the total cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between these items on the statement of cash flows. The guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The ASU provides final guidance on eight cash flow issues, including debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, distributions received from equity method investees, separately identifiable cash flows and application of the predominance principle, and others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted the guidance effective January 1, 2017 and there was no impact on the Company’s consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The guidance changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The guidance replaces the current ‘incurred loss’ model with an ‘expected loss’ approach. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted after December 2018. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, Investments Equity Method and Joint Ventures (Topic 323). The guidance eliminates the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. The Company adopted the guidance effective January 1, 2017 and there was no impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases. The guidance requires lessees to recognize lease assets and lease liabilities for those leases classified as operating leases under the previous standard. Depending on the lease classification, lessees will recognize expense based on the effective interest method for finance leases or on a straight-line basis for operating leases. The accounting applied by a lessor is largely unchanged from that applied under the previous standard. One of the impacts on the Company will be the presentation and disclosure in the financial statements of non-lease components such as charges to tenants for a building’s operating expenses. The non-lease components will be presented separately from the lease components in both the Consolidated Statements of Operations and Consolidated Balance Sheets. Another impact is the measurement and presentation of ground leases under which the Company is lessee. The Company is required to record a liability for the obligation to make payments under the lease and an asset for the right to use the underlying asset during the lease term and will also apply the new expense recognition requirements given the lease classification. The Company is currently quantifying these impacts. The guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company anticipates adopting this guidance January 1, 2019 and will apply the modified retrospective approach. In January 2016, the FASB issued ASU 2016-01 (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to record changes in instruments-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. The guidance is effective for fiscal years beginning after December 15, 2017, and for interim periods therein. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In May 2014, the FASB issued a new comprehensive revenue recognition guidance which requires us to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods and services (ASU 2014-09). The FASB also issued implementation guidance in March 2016, April 2016 and May 2016 - ASU’s 2016-08, 2016-10 and 2016-12, respectively. These ASUs are effective for annual and interim periods beginning after December 15, 2017. The Company will adopt this guidance January 1, 2018. Since the Company’s revenue is related to leasing activities, the adoption of this guidance will not have a material impact on the consolidated financial statements. The new guidance is applicable to service contracts with joint ventures for which the Company earns property management fees, leasing commissions and development and construction fees. The adoption of this new guidance does not change the accounting for these fees as the pattern of recognition of revenue does not change with the new guidance. We will continue to recognize revenue over time on these contracts because the customer simultaneously receives and consumes the benefits provided by our performance. Thus, the analysis of our contracts under the new revenue recognition standard is consistent with our current revenue recognition model.
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 primarily utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, as well as sales comparison approach, which utilizes comparable sales, listings and sales contracts. All of which are classified as Level 3 inputs. As of September 30, 2017 we held notes receivable totaling $250.0 million which were purchased at par, and were in maturity default at the time of acquisition. In August 2017, the Company determined that it was probable that the loans would not be repaid in full and therefore, the loans were put on non-accrual status. The Company has initiated proceedings to foreclose on the property, and expects to take control of the property unless the buyer is able to repay the principal and interest, including default interest and fees, on the notes receivable in full prior to the completion of the foreclosure process. We believe the collateral value is sufficient to recover the carrying amounts of the notes receivable. 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 instrument to their present value using adjusted market interest rates, which is provided by a third-party specialist.

Organization and Basis of Pre25

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of September 30, 2017 , 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, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties: Location Type Number of Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office 16 8,463,245 95.7 % Retail (2)(3) 5 364,816 98.0 % Fee Interest 1 176,530 100.0 % 22 9,004,591 95.9 % Suburban Office (4) 15 2,746,000 84.6 % Retail 1 52,000 100.0 % 16 2,798,000 84.9 % Total commercial properties 38 11,802,591 93.2 % Residential: Manhattan Residential (2) — 222,855 88.0 % Total portfolio 38 12,025,446 93.2 % (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 September 30, 2017 , we owned a building at 315 West 33rd Street, also known as The Olivia, 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 this 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. (3) Includes two unconsolidated joint venture retail properties at 131-137 Spring Street comprised of approximately 68,342 square feet. (4) Includes the properties at 16 Court Street in Brooklyn, New York, and 125 Chubb Avenue in Lyndhurst, New Jersey which are classified as held for sale at September 30, 2017. The sales closed in October 2017.

Significant Accounting Polici26

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
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 September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Identified intangible assets (included in other assets): Gross amount $ 285,271 $ 311,830 Accumulated amortization (241,949 ) (253,064 ) Net (1) $ 43,322 $ 58,766 Identified intangible liabilities (included in deferred revenue): Gross amount $ 508,373 $ 524,793 Accumulated amortization (372,190 ) (368,738 ) Net (1) $ 136,183 $ 156,055 (1) As of September 30, 2017 and December 31, 2016, $3.9 million and none , respectively and $1.1 million and none , respectively, of net intangible assets and net intangible liabilities, were reclassified to assets held for sale and liabilities related to assets held for sale.

Properties Held for Sale and 27

Properties Held for Sale and Property Dispositions (Tables)	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Schedule of properties sold and income from discontinued operations	The following table summarizes the properties sold during the nine months ended September 30, 2017 : Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain (loss) (2) (in millions) 520 White Plains Road April 2017 Office 180,000 $ 21.0 $ (14.6 ) 102 Greene Street (3) April 2017 Retail 9,200 43.5 4.9 680-750 Washington Boulevard July 2017 Office 325,000 97.0 (44.2 ) (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 102 Greene Street is net of $0.9 million in employee compensation awards accrued in connection with the realization of the investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, gain on sale amounts do not include adjustments for expenses recorded in subsequent periods. (3) In April 2017, we closed on the sale of a 90% interest in 102 Greene Street and had subsequently accounted for our interest in the property as an investment in unconsolidated joint ventures. We sold the remaining 10% interest in September 2017. See Note 6, "Investments in Unconsolidated Joint Ventures".

Debt and Preferred Equity Inv28

Debt and Preferred Equity Investments (Tables)	9 Months Ended
	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of debt and preferred equity book balance roll forward	Below is the rollforward analysis of the activity relating to our debt and preferred equity investments as of September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Balance at beginning of period (1) $ 1,640,412 $ 1,670,020 Debt Investment Originations/Accretion (2) 944,494 1,009,176 Preferred Equity Investment Originations/Accretion (2) 144,013 5,698 Redemptions/Sales/Syndications/Amortization (3) (708,180 ) (1,044,482 ) Balance at end of period (1) $ 2,020,739 $ 1,640,412 (1) Net of unamortized fees, discounts, and premiums. (2) Accretion includes amortization of fees and discounts and paid-in-kind investment income. (3) Certain participations in debt investments that were sold or syndicated did not meet the conditions for sale accounting are included in other assets and other liabilities on the consolidated balance sheets.
Summary of debt investments	As of September 30, 2017 and December 31, 2016 , we held the following debt investments with an aggregate weighted average current yield of 9.49% , excluding our investment in Two Herald Square, at September 30, 2017 (in thousands): Loan Type September 30, 2017 Future Funding Obligations September 30, 2017 Senior September 30, 2017 (1) December 31, 2016 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Mortgage/Jr. Mortgage Loan (3) $ — $ — $ 250,164 $ — April 2017 Mortgage Loan (4) — — 26,352 26,311 February 2019 Mortgage Loan — — 275 380 August 2019 Mezzanine Loan (5a) — 1,160,000 201,757 — March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,909 — April 2022 Mezzanine Loan — 87,595 12,697 12,692 November 2023 Mezzanine Loan (5b) — 115,000 12,930 12,925 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 15,000 15,000 November 2026 Mezzanine Loan — 1,657,500 55,250 — June 2027 Mezzanine Loan (6) — — — 66,129 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 193,422 Total fixed rate $ — $ 3,617,095 $ 632,834 $ 360,359 Floating Rate Investments: Mortgage/Mezzanine Loan (8) 622 — 23,372 20,423 October 2017 Mezzanine Loan (5c) — 85,000 15,340 15,141 December 2017 Mezzanine Loan (5d) — 65,000 14,832 14,656 December 2017 Mezzanine Loan (5e) 795 — 15,132 15,051 December 2017 Mortgage/Mezzanine Loan (9) — 125,000 29,966 29,998 January 2018 Mezzanine Loan — 40,000 19,964 19,913 April 2018 Jr. Mortgage Participation — 117,808 34,899 34,844 April 2018 Mezzanine Loan 523 20,523 10,916 10,863 August 2018 Mortgage/Mezzanine Loan — — 19,914 19,840 August 2018 Mortgage Loan — 65,000 14,935 14,880 August 2018 Loan Type September 30, 2017 Future Funding Obligations September 30, 2017 Senior September 30, 2017 (1) December 31, 2016 Carrying Value (1) Maturity Date (2) Mortgage/Mezzanine Loan (10) — — 16,957 16,960 September 2018 Mezzanine Loan — 37,500 14,801 14,648 September 2018 Mezzanine Loan 2,325 45,025 34,782 34,502 October 2018 Mezzanine Loan — 335,000 74,683 74,476 November 2018 Mezzanine Loan — 33,000 26,907 26,850 December 2018 Mezzanine Loan 1,050 171,939 58,598 56,114 December 2018 Mezzanine Loan 8,267 289,621 71,067 63,137 December 2018 Mezzanine Loan 5,197 229,084 74,314 64,505 December 2018 Mezzanine Loan — 45,000 12,156 12,104 January 2019 Mortgage/Mezzanine Loan (5f) 30,101 — 158,757 — January 2019 Mezzanine Loan 6,081 24,086 7,812 5,410 January 2019 Mezzanine Loan — 38,000 21,927 21,891 March 2019 Mezzanine Loan 279 173,700 36,936 — April 2019 Mezzanine Loan — 265,000 24,798 24,707 April 2019 Mortgage/Jr. Mortgage Participation Loan 29,661 194,094 69,705 65,554 August 2019 Mezzanine Loan 2,034 187,500 37,835 37,322 September 2019 Mortgage/Mezzanine Loan 49,933 — 130,350 111,819 September 2019 Mortgage/Mezzanine Loan 30,494 — 38,934 33,682 January 2020 Mezzanine Loan (11) 6,794 537,748 72,597 125,911 January 2020 Mezzanine Loan 7,164 33,587 10,988 — July 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,627 15,606 July 2021 Mezzanine Loan — 280,000 34,124 — August 2022 Mezzanine Loan (12) — — — 15,369 Mortgage/ Mezzanine Loan (6) — — — 32,847 Mortgage/Mezzanine Loan (6) — — — 22,959 Mezzanine Loan (13) — — — 14,957 Mortgage/Mezzanine Loan (14) — — — 145,239 Total floating rate $ 181,320 $ 3,498,215 $ 1,243,925 $ 1,232,178 Total $ 181,320 $ 7,115,310 $ 1,876,759 $ 1,592,537 (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) These loans were purchased at par in April and May 2017 and were in maturity default at the time of acquisition. At the time the loans were purchased, the Company expected to collect all contractually required payments, including interest. In August 2017, the Company determined that it was probable that the loans would not be repaid in full and therefore, the loans were put on non-accrual status. No impairment was recorded as the Company believes that the fair value of the property exceeds the carrying amount of the loans. The loans had an outstanding balance including accrued interest of $259.3 million at the time that they were put on non-accrual status. (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, is currently on non-accrual status and has no carrying value. (5) Carrying value is net of the following amounts that were sold or syndicated, which are included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting: (a) $1.2 million , (b) $12.0 million , (c) $14.6 million , (d) $14.1 million , (e) $5.1 million , and (f) $21.2 million (6) This loan was repaid in June 2017. (7) This loan was repaid in March 2017. (8) This loan was extended in October 2017. (9) This loan was extended in January 2017. (10) This loan was extended in September 2017. (11) $66.1 million of outstanding principal was syndicated in February 2017. (12) This loan was repaid in September 2017. (13) This loan was contributed to a joint venture in May 2017. (14) This loan was repaid in January 2017.
Schedule of preferred equity investments	s of September 30, 2017 and December 31, 2016 , we held the following preferred equity investments with an aggregate weighted average current yield of 6.98% at September 30, 2017 (in thousands): Type September 30, 2017 September 30, 2017 September 30, 2017 (1) December 31, 2016 (1) Mandatory Redemption (2) Preferred Equity (3) $ — $ 272,000 $ 143,980 $ — April 2021 Preferred Equity (4) — — — 9,982 Preferred Equity (5) — — — 37,893 Total $ — $ 272,000 $ 143,980 $ 47,875 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) In February 2016, we closed on the sale of 885 Third Avenue and retained a preferred equity position in the property. The sale 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 remained on our consolidated balance sheet until the criteria was met in April 2017 at which time the property was deconsolidated and the preferred equity investment was recognized. (4) This investment was redeemed in May 2017. (5) This investment was redeemed in April 2017.

Investments in Unconsolidated29

Investments in Unconsolidated Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Schedule of general information on joint ventures	As of September 30, 2017 and December 31, 2016 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type September 30, 2017 December 31, 2016 Maturity Date Mezzanine Loan and Preferred Equity (1) $ 100,000 $ 100,000 March 2018 Mezzanine Loan (2) 25,854 24,542 July 2036 $ 125,854 $ 124,542 (1) These loans were extended in February 2017. (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 following table summarizes the investments in unconsolidated joint ventures sold during the nine months ended September 30, 2017 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain on Sale (in thousands) (2) 102 Greene Street 10.00% September 2017 Ownership Interest $ 43,500 $ 283 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. The table below provides general information on each of our joint ventures as of September 30, 2017 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 $ 277,750 Mezzanine Loan (3) Private Investors 33.33% 33.33% — May 2017 15,000 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of September 30, 2017 . Changes in ownership or economic interests, if any, 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 May 2017, the Company contributed a mezzanine loan secured by a commercial property in midtown Manhattan to a joint venture and retained a 33.33% interest in the venture. The carrying value is net of $10.0 million that was sold, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting.
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 September 30, 2017 and December 31, 2016 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) September 30, 2017 December 31, 2016 Floating Rate Debt: 131-137 Spring Street 20.00 % August 2020 2.77 % $ 141,000 $ 141,000 Total joint venture mortgages and other loans payable $ 141,000 $ 141,000 Deferred financing costs, net (3,139 ) (3,970 ) Total joint venture mortgages and other loans payable, net $ 137,861 $ 137,030 (1) Economic interest represent the Company's interests in the joint venture as of September 30, 2017 . Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures note above. (2) Effective weighted average interest rate for the three months ended September 30, 2017 , taking into account interest rate hedges in effect during the period.
Schedule of combined balance sheets for the unconsolidated joint ventures	. The combined balance sheets for the unconsolidated joint ventures, at September 30, 2017 and December 31, 2016 are as follows (in thousands): September 30, 2017 December 31, 2016 Assets Commercial real estate property, net $ 274,695 $ 279,451 Debt and preferred equity investments, net 140,850 273,749 Other assets 15,019 18,922 Total assets $ 430,564 $ 572,122 Liabilities and members' equity Mortgages and other loans payable, net $ 137,861 $ 137,030 Other liabilities 19,764 22,185 Members' equity 272,939 412,907 Total liabilities and members' equity $ 430,564 $ 572,122 Company's investments in unconsolidated joint ventures $ 128,794 $ 174,127
Schedule of combined statements of operations for the unconsolidated joint ventures	September 30, 2017 December 31, 2016 Assets Commercial real estate property, net $ 274,695 $ 279,451 Debt and preferred equity investments, net 140,850 273,749 Other assets 15,019 18,922 Total assets $ 430,564 $ 572,122 Liabilities and members' equity Mortgages and other loans payable, net $ 137,861 $ 137,030 Other liabilities 19,764 22,185 Members' equity 272,939 412,907 Total liabilities and members' equity $ 430,564 $ 572,122 Company's investments in unconsolidated joint ventures $ 128,794 $ 174,127 The combined statements of operations for the unconsolidated joint ventures for the three and nine months ended September 30, 2017 and 2016 , are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Total revenues $ 7,340 $ 3,707 $ 26,934 $ 27,590 Operating expenses 182 (175 ) 636 1,003 Real estate taxes 381 33 1,013 881 Interest expense, net of interest income 1,025 37 2,759 2,144 Amortization of deferred financing costs 283 — 837 831 Depreciation and amortization 2,102 — 6,304 6,303 Total expenses $ 3,973 $ (105 ) $ 11,549 $ 11,162 Net income $ 3,367 $ 3,812 $ 15,385 $ 16,428 Company's equity in net income from unconsolidated joint ventures $ 2,927 $ 4,276 $ 10,362 $ 10,399

Mortgages and Other Loans Pay30

Mortgages and Other Loans Payable (Tables)	9 Months Ended
	Sep. 30, 2017
Mortgage Note and Other Loans Payable
Schedule of the first mortgage note and other loans payable collateralized by the property, assignment of leases and investment	The first mortgages and other loans payable collateralized by the respective properties and assignment of leases or debt investments at September 30, 2017 and December 31, 2016 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2017 December 31, 2016 Fixed Rate Debt: 919 Third Avenue (2) June 2023 5.12 % $ 500,000 $ 500,000 315 West 33rd Street February 2027 4.24 % 250,000 — Floating Rate Debt: 2016 Master Repurchase Agreement July 2018 3.73 % $ 184,642 $ 184,642 Total mortgages and other loans payable $ 934,642 $ 684,642 Deferred financing costs, net of amortization (12,593 ) (8,574 ) Total mortgages and other loans payable, net $ 922,049 $ 676,068 (1) Effective weighted average interest rate for the quarter ended September 30, 2017 . (2) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan.

Corporate Indebtedness (Tables)

Corporate Indebtedness (Tables)	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017 and December 31, 2016 , respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, Coupon (1) Effective Initial Maturity Date August 5, 2011 (2) $ 250,000 $ 249,934 $ 249,880 5.00 % 5.00 % 7 August 2018 March 16, 2010 (2) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (2) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (2) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 $ 800,000 $ 799,934 $ 799,880 Deferred financing costs, net (3,650 ) (4,620 ) $ 800,000 $ 796,284 $ 795,260 (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 SL Green, the Operating Partnership and ROP, as co-obligors. In October 2017, SL Green, the Operating Partnership and ROP, as co-obligors issued an additional $100.0 million of the 4.50% senior unsecured bonds due December 2022. The additional notes priced at 105.334% plus accrued interest from June 1, 2017, with a yield to maturity of 3.298% .
Schedule of combined aggregate principal maturities of mortgage and other loans payable, 2012 credit facility and senior unsecured notes, including as-of-right extension options	Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility and senior unsecured notes as of September 30, 2017 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Revolving Unsecured Term Loan Senior Unsecured Notes Total Remaining 2017 $ — $ — $ — $ — $ — $ — 2018 — 184,642 — — 250,000 434,642 2019 — — 280,000 1,183,000 — 1,463,000 2020 — — — — 250,000 250,000 2021 — — — — — — Thereafter — 750,000 — — 300,000 1,050,000 $ — $ 934,642 $ 280,000 $ 1,183,000 $ 800,000 $ 3,197,642
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Interest expense before capitalized interest $ 34,658 $ 25,087 $ 96,740 $ 84,175 Interest capitalized (31 ) (362 ) (533 ) (799 ) Interest income — (2 ) (5 ) (9 ) Interest expense, net $ 34,627 $ 24,723 $ 96,202 $ 83,367

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The following table provides the carrying value and fair value of these financial instruments as of September 30, 2017 and December 31, 2016 (in thousands): September 30, 2017 December 31, 2016 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 2,020,739 (2) $ 1,640,412 (2) Fixed rate debt $ 2,349,934 $ 2,441,240 $ 2,099,880 $ 2,183,042 Variable rate debt 847,642 855,640 567,642 580,083 $ 3,197,576 $ 3,296,880 $ 2,667,522 $ 2,763,125 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2017 , debt and preferred equity investments had an estimated fair value ranging between $2.0 billion and $2.2 billion . At December 31, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.6 billion and $1.8 billion .

Financial Instruments_ Deriva33

Financial Instruments: Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of effect of derivative financial instruments on consolidated statements of income	The following table presents the effect of our derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the three months ended September 30, 2017 and 2016 , respectively (in thousands): Amount of (Loss) 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 Gain Recognized in Income on Derivative Amount of Gain Recognized into Income (Ineffective Portion) Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Derivative 2017 2016 2017 2016 2017 2016 Interest Rate Swap $ — $ — Interest expense $ 89 $ 90 Interest expense $ — $ — The following table presents the effect of our derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of operations for the nine months ended September 30, 2017 and 2016 , respectively (in thousands): Amount of (Loss) Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of Gain Recognized in Income on Derivative Amount of Gain Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2017 2016 2017 2016 2017 2016 Interest Rate Swap $ — $ (13 ) Interest expense $ 269 $ 521 Interest expense $ — $ 3

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments under capital leases and noncancellable operating leases	The following is a schedule of future minimum lease payments under non-cancellable operating leases with initial terms in excess of one year as of September 30, 2017 (in thousands): Non-cancellable operating leases Remaining 2017 $ 5,147 2018 20,586 2019 20,586 2020 20,586 2021 20,736 Thereafter 308,202 Total minimum lease payments $ 395,843

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected consolidated results of operations for the three and nine months ended September 30, 2017 and 2016 , and selected asset information as of September 30, 2017 and December 31, 2016 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Three months ended: September 30, 2017 $ 193,962 $ 47,946 $ 241,908 September 30, 2016 195,621 75,715 271,336 Nine months ended: September 30, 2017 $ 577,151 $ 148,924 $ 726,075 September 30, 2016 567,277 175,481 742,758 Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves Three months ended: September 30, 2017 $ 24,705 $ 39,988 $ 64,693 September 30, 2016 27,975 74,948 102,923 Nine months ended: September 30, 2017 $ 87,700 $ 131,524 $ 219,224 September 30, 2016 82,430 167,613 250,043 Total assets Real Estate Segment Debt and Preferred Equity Segment Total Company As of: September 30, 2017 $ 6,563,972 $ 2,189,588 $ 8,753,560 December 31, 2016 6,785,305 1,969,308 8,754,613
Schedule of reconciliation of income from continuing operations to net income attributable to common stockholders	The table below reconciles income from continuing operations to net income for the three and nine months ended September 30, 2017 and 2016 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves $ 64,693 $ 102,923 $ 219,224 $ 250,043 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 282 — 285 — Gain (loss) on sale of real estate 114 — 5,047 (6,899 ) Depreciable real estate reserves (379 ) — (85,707 ) — Net income $ 64,710 $ 102,923 $ 138,849 $ 243,144

Organization and Basis of Pre36

Organization and Basis of Presentation (Details) $ in Billions	9 Months Ended
	Sep. 30, 2017USD ($)ft²property
Real estate properties
Percentage of ownership in SL Green Operating Partnership owned by SL Green Realty Corp (as a percent)	95.55%
Number of Properties | property	38
Approximate Square Feet (sqft)	12,025,446
Weighted Average Occupancy (as a percent)	93.20%
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $	$ 2.2
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $	$ 0.1
Manhattan
Real estate properties
Number of Properties | property	22
Approximate Square Feet (sqft)	9,004,591
Weighted Average Occupancy (as a percent)	95.90%
Suburban
Real estate properties
Number of Properties | property	16
Approximate Square Feet (sqft)	2,798,000
Weighted Average Occupancy (as a percent)	84.90%
Office | Manhattan
Real estate properties
Number of Properties | property	16
Approximate Square Feet (sqft)	8,463,245
Weighted Average Occupancy (as a percent)	95.70%
Office | Suburban
Real estate properties
Number of Properties | property	15
Approximate Square Feet (sqft)	2,746,000
Weighted Average Occupancy (as a percent)	84.60%
Retail | 131-137 Spring Street
Real estate properties
Approximate Square Feet (sqft)	68,342
Number of unconsolidated joint venture properties | property	2
Retail | Manhattan
Real estate properties
Number of Properties | property	5
Approximate Square Feet (sqft)	364,816
Weighted Average Occupancy (as a percent)	98.00%
Retail | Suburban
Real estate properties
Number of Properties | property	1
Approximate Square Feet (sqft)	52,000
Weighted Average Occupancy (as a percent)	100.00%
Fee Interest | Manhattan
Real estate properties
Number of Properties | property	1
Approximate Square Feet (sqft)	176,530
Weighted Average Occupancy (as a percent)	100.00%
Commercial
Real estate properties
Number of Properties | property	38
Approximate Square Feet (sqft)	11,802,591
Weighted Average Occupancy (as a percent)	93.20%
Residential | Manhattan
Real estate properties
Number of Properties | property	0
Approximate Square Feet (sqft)	222,855
Weighted Average Occupancy (as a percent)	88.00%
Dual property type, retail portion
Real estate properties
Approximate Square Feet (sqft)	270,132
Dual property type, residential portion
Real estate properties
Approximate Square Feet (sqft)	222,855

Significant Accounting Polici37

Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Investment in Commercial Real Estate Properties
Depreciable real estate reserves	$ (379,000)	$ 0	$ (85,707,000)	$ 0
Increase in rental revenue from amortization of acquired leases	4,300,000	$ 8,100,000	12,700,000	$ 15,900,000
Identified intangible assets (included in other assets):
Gross amount	285,271,000		285,271,000		$ 311,830,000
Accumulated amortization	(241,949,000)		(241,949,000)		(253,064,000)
Net	43,322,000		43,322,000		58,766,000
Identified intangible liabilities (included in deferred revenue):
Gross amount	508,373,000		508,373,000		524,793,000
Accumulated amortization	(372,190,000)		(372,190,000)		(368,738,000)
Net	136,183,000		136,183,000		156,055,000
Net Intangible Assets Transferred to Assets Held for Sale	3,900,000		3,900,000		0
Net Intangible Liabilities Transferred to Liabilities Related to Assets Held for Sale	1,100,000		$ 1,100,000		$ 0
Above-market leases | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			1 year
Above-market leases | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			14 years
Below-market leases | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			1 year
Below-market leases | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			14 years
In-place leases | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			1 year
In-place leases | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of intangible assets (years)			14 years
Building | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life (years)			3 years
Building | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (years)			40 years
125 Chubb Avenue and Stamford Towers
Investment in Commercial Real Estate Properties
Depreciable real estate reserves	$ 400,000		$ 85,700,000

Significant Accounting Polici38

Significant Accounting Policies - Concentrations of Credit Risk/Reclassification (Details) - Annualized cash rent - Customer concentration	3 Months Ended
	Sep. 30, 2017
Concentrations of Credit Risk
Maximum percentage of annualized cash rent for any one tenant not individually disclosed	5.00%
1185 Avenue of the Americas
Concentrations of Credit Risk
Percentage of concentration	13.80%
625 Madison Avenue
Concentrations of Credit Risk
Percentage of concentration	9.10%
919 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	7.40%
750 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	7.20%
810 Seventh Avenue
Concentrations of Credit Risk
Percentage of concentration	7.10%
555 W. 57th Street
Concentrations of Credit Risk
Percentage of concentration	6.30%
125 Park Avenue
Concentrations of Credit Risk
Percentage of concentration	6.10%
1350 Avenue of the Americas
Concentrations of Credit Risk
Percentage of concentration	5.90%

Properties Held for Sale and 39

Properties Held for Sale and Property Dispositions (Details) $ in Millions	1 Months Ended			9 Months Ended
	Sep. 30, 2017ft²	Jul. 31, 2017USD ($)ft²	Apr. 30, 2017USD ($)ft²	Sep. 30, 2017USD ($)ft²	Oct. 31, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²	12,025,446			12,025,446
680-750 Washington Boulevard
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²		325,000
Sales Price		$ 97
Gain (loss)		$ (44.2)
102 Greene Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²			9,200
Sales Price			$ 43.5
Gain (loss)			$ 4.9
Employee compensation awards accrued				$ 0.9
Joint venture, ownership percentage sold	10.00%		90.00%
520 White Plains Road
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²			180,000
Sales Price			$ 21
Gain (loss)			$ (14.6)
Subsequent Event | 16 Court Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales Price					$ 171

Debt and Preferred Equity Inv40

Debt and Preferred Equity Investments - Debt and Preferred Equity Investment Rollforward (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Mortgage Loans on Real Estate [Line Items]
Balance at beginning of period	$ 1,640,412	$ 1,670,020
Redemptions/Sales/Syndications/Amortization	(708,180)	(1,044,482)
Balance at end of period	2,020,739	1,640,412
Debt Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Originations/Accretion	944,494	1,009,176
Preferred Equity Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Originations/Accretion	$ 144,013	$ 5,698

Debt and Preferred Equity Inv41

Debt and Preferred Equity Investments (Details)	9 Months Ended
	Sep. 30, 2017USD ($)segment	Sep. 30, 2016segment	Feb. 28, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 24, 2014USD ($)
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	9.49%
Debt Investments Held [Abstract]
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 2,020,739,000			$ 1,640,412,000
Number of portfolio segments | segment	1	1
Financing receivables included in other assets	$ 94,800,000			144,500,000
Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017
Debt Investments Held [Abstract]
Mortgage Loans on Real Estate, Commercial and Consumer, Net	250,200,000			0	$ 0
Mezzanine Loan with an Initial Maturity Date of March 2020
Debt Investments Held [Abstract]
Amount participated out	1,200,000
Mezzanine Loan with an Initial Maturity Date of June 2024
Debt Investments Held [Abstract]
Amount participated out	12,000,000
Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Amount participated out	14,600,000
Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Amount participated out	14,100,000
Mezzanine Loan with an Initial Maturity Date of December 2017
Debt Investments Held [Abstract]
Amount participated out	5,100,000
Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2019
Debt Investments Held [Abstract]
Amount participated out	21,200,000
Debt Investments in Mortgage Loans
Debt Investments Held [Abstract]
Future Funding Obligations	181,320,000
Senior Financing	7,115,310,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 1,876,759,000			1,592,537,000
Preferred Equity Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	6.98%
Debt Investments Held [Abstract]
Future Funding Obligations	$ 0
Senior Financing	272,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	143,980,000			47,875,000
Preferred Equity, April 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	272,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	143,980,000			0
Preferred Equity Redeemed in May 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			9,982,000
Preferred Equity Redeemed in April 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			37,893,000
Junior Mortgage Participation Acquired in September 2014
Debt Investments Held [Abstract]
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			0	$ 0		$ 0
Fixed Rate Investments
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	3,617,095,000
Carrying Value, Net of Discounts and Deferred Origination Fees	632,834,000			360,359,000
Fixed Rate Investments | Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	250,164,000			0
Loan acquired	259,300,000
Fixed Rate Investments | Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	26,352,000			26,311,000
Loan acquired						$ 26,400,000
Discount on loan acquired						200,000
Fixed Rate Investments | Mortgage Loan, August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	275,000			380,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity Date of March 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,160,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	201,757,000			0
Fixed Rate Investments | Mezzanine Loan, September 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	3,500,000			3,500,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity Date of April 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	147,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	24,909,000			0
Fixed Rate Investments | Mezzanine Loan, with an Initial Maturity Date of November 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	87,595,000
Carrying Value, Net of Discounts and Deferred Origination Fees	12,697,000			12,692,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity Date of June 2024
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	12,930,000			12,925,000
Fixed Rate Investments | Mezzanine Loan, with an Initial Maturity Date of January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	30,000,000			30,000,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity Date of November 2026
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	340,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	15,000,000			15,000,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity Date of June 2027
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,657,500,000
Carrying Value, Net of Discounts and Deferred Origination Fees	55,250,000			0
Fixed Rate Investments | Mezzanine Loan Repaid in June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			66,129,000
Fixed Rate Investments | Junior Mortgage Participation or Mezzanine Loan repaid in March 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			193,422,000
Fixed Rate Investments | Junior Mortgage Participation, Related To Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Loan acquired						5,700,000
Discount on loan acquired						$ 5,700,000
Floating Rate Investments
Debt Investments Held [Abstract]
Future Funding Obligations	181,320,000
Senior Financing	3,498,215,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	1,243,925,000			1,232,178,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2017
Debt Investments Held [Abstract]
Future Funding Obligations	622,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	23,372,000			20,423,000
Floating Rate Investments | Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	15,340,000			15,141,000
Floating Rate Investments | Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	14,832,000			14,656,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	795,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	15,132,000			15,051,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	125,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	29,966,000			29,998,000
Floating Rate Investments | Mezzanine Loan, April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	19,964,000			19,913,000
Floating Rate Investments | Junior Participation Loan, April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	117,808,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	34,899,000			34,844,000
Floating Rate Investments | Mezzanine Loan, August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	523,000
Senior Financing	20,523,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	10,916,000			10,863,000
Floating Rate Investments | Mortgage/Mezzanine Loan, with an Initial Maturity Date of August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	19,914,000			19,840,000
Floating Rate Investments | Mortgage Loan with an Initial Maturity Date of August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	14,935,000			14,880,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of September 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	16,957,000			16,960,000
Floating Rate Investments | Mezzanine Loan, September 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	37,500,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	14,801,000			14,648,000
Floating Rate Investments | Mezzanine Loan, October 2018
Debt Investments Held [Abstract]
Future Funding Obligations	2,325,000
Senior Financing	45,025,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	34,782,000			34,502,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of November 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	335,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	74,683,000			74,476,000
Floating Rate Investments | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	33,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	26,907,000			26,850,000
Floating Rate Investments | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	1,050,000
Senior Financing	171,939,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	58,598,000			56,114,000
Floating Rate Investments | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	8,267,000
Senior Financing	289,621,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	71,067,000			63,137,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	5,197,000
Senior Financing	229,084,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	74,314,000			64,505,000
Floating Rate Investments | Mezzanine Loan, January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	45,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	12,156,000			12,104,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	30,101,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	158,757,000			0
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	6,081,000
Senior Financing	24,086,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	7,812,000			5,410,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of March 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	21,927,000			21,891,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	279,000
Senior Financing	173,700,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	36,936,000			0
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	265,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	24,798,000			24,707,000
Floating Rate Investments | Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	29,661,000
Senior Financing	194,094,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	69,705,000			65,554,000
Floating Rate Investments | Mezzanine Loan, Maturity of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	2,034,000
Senior Financing	187,500,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	37,835,000			37,322,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	49,933,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	130,350,000			111,819,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	30,494,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	38,934,000			33,682,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	6,794,000
Senior Financing	537,748,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	72,597,000		$ 66,100,000	125,911,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of July 2020 [Domain]
Debt Investments Held [Abstract]
Future Funding Obligations	7,164,000
Senior Financing	33,587,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	10,988,000			0
Floating Rate Investments | Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	15,627,000			15,606,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of August 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	280,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	34,124,000			0
Floating Rate Investments | Mezzanine Loan, repaid in September 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			15,369,000
Floating Rate Investments | Mortgage/Mezzanine Loan, repaid in June 2017, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			32,847,000
Floating Rate Investments | Mortgage/Mezzanine Loan, repaid in June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			22,959,000
Floating Rate Investments | Mezzanine Loan Contributed for a Joint Venture Interest
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0			14,957,000
Floating Rate Investments | Mortgage/Mezzanine Loan, repaid in January 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 0			$ 145,239,000

Investments in Unconsolidated42

Investments in Unconsolidated Joint Ventures - Additional Information (Details) $ in Thousands	1 Months Ended
	May 31, 2017USD ($)note	Sep. 30, 2017USD ($)ft²	Apr. 30, 2017ft²	Dec. 31, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Unaudited Approximate Square Feet (sqft) | ft²		12,025,446
Acquisition, development and construction arrangements, carrying value		$ 125,854		$ 124,542
Mezzanine Loan
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)	33.33%	33.33%
Economic Interest (as a percent)		33.33%
Unaudited Approximate Square Feet (sqft) | ft²		0
Acquisition Price		$ 15,000
Equity method investment, amount sold	$ 10,000
Mezzanine Loan and Preferred Equity Due March 2018
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value		100,000		100,000
Mezzanine Loan Due July 2036
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value		$ 25,854		$ 24,542
131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)		20.00%
Economic Interest (as a percent)		20.00%
Unaudited Approximate Square Feet (sqft) | ft²		68,342
Acquisition Price		$ 277,750
102 Greene Street
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)		10.00%
102 Greene Street
Schedule of Equity Method Investments [Line Items]
Unaudited Approximate Square Feet (sqft) | ft²			9,200
76 11th Avenue
Schedule of Equity Method Investments [Line Items]
Number of mezzanine notes owned | note	2

- Mortgages and Loans Payable (

- Mortgages and Loans Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Joint Venture
Schedule of Equity Method Investments [Line Items]
Total joint venture mortgages and other loans payable	$ 141,000	$ 141,000
Deferred financing costs, net	(3,139)	(3,970)
Total joint venture mortgages and other loans payable, net	$ 137,861	137,030
131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Economic Interest (as a percent)	20.00%
131-137 Spring Street | Joint Venture
Schedule of Equity Method Investments [Line Items]
Floating rate debt	$ 141,000	$ 141,000
Weighted Average | 131-137 Spring Street | Joint Venture
Schedule of Equity Method Investments [Line Items]
Interest rate (as a percent)	2.77%

Investments in Unconsolidated44

Investments in Unconsolidated Joint Ventures - Sale of Joint Venture Interests or Properties (Details) - 102 Greene Street $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Schedule of Equity Method Investments [Line Items]
Ownership Interest	10.00%
Gross Asset Valuation	$ 43,500
Gain on Sale	$ 283

Investments in Unconsolidated45

Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Assets
Commercial real estate property, net	$ 5,694,777		$ 5,694,777		$ 6,071,648
Other assets	289,841		289,841		374,091
Liabilities and members' equity
Mortgages and other loans payable, net	922,049		922,049		676,068
Other liabilities	94,426		94,426		160,982
Company's investments in unconsolidated joint ventures	128,794		128,794		174,127
Combined statements of income for the unconsolidated joint ventures
Real estate taxes	40,610	$ 38,900	118,232	$ 113,426
Amortization of deferred financing costs	2,580	2,081	6,706	5,953
Depreciation and amortization	53,549	57,916	156,106	159,365
Total expenses	180,142	172,689	517,213	503,114
Company's equity in net income from unconsolidated joint ventures	2,927	4,276	10,362	10,399
Joint Venture
Assets
Commercial real estate property, net	274,695		274,695		279,451
Debt and preferred equity investments, net	140,850		140,850		273,749
Other assets	15,019		15,019		18,922
Total assets	430,564		430,564		572,122
Liabilities and members' equity
Mortgages and other loans payable, net	137,861		137,861		137,030
Other liabilities	19,764		19,764		22,185
Members' equity	272,939		272,939		412,907
Total liabilities and members' equity	430,564		430,564		$ 572,122
Combined statements of income for the unconsolidated joint ventures
Total revenues	7,340	3,707	26,934	27,590
Operating expenses	182	(175)	636	1,003
Real estate taxes	381	33	1,013	881
Interest expense, net of interest income	1,025	37	2,759	2,144
Amortization of deferred financing costs	283	0	837	831
Depreciation and amortization	2,102	0	6,304	6,303
Total expenses	3,973	(105)	11,549	11,162
Net income	3,367	3,812	15,385	16,428
Company's equity in net income from unconsolidated joint ventures	$ 2,927	$ 4,276	$ 10,362	$ 10,399

Mortgages and Other Loans Pay46

Mortgages and Other Loans Payable (Details)	Dec. 06, 2015USD ($)	Sep. 30, 2017USD ($)extenstion_optiondebt_instrument	Dec. 31, 2016USD ($)
Mortgage note and other loan payable
Total mortgages and other loans payable		$ 934,642,000	$ 684,642,000
Deferred financing costs, net of amortization		(12,593,000)	(8,574,000)
Total mortgages and other loans payable, net		922,049,000	676,068,000
Debt and preferred equity investments		$ 2,500,000,000	1,700,000,000
Number of extension options | extenstion_option		2
Period of extension option		1 year
Revolving credit facility, net		$ 275,832,000	0
Master Repurchase Agreement
Mortgage note and other loan payable
Floating rate debt		184,642,000	184,642,000
Maximum borrowing capacity		$ 300,000,000
Initial term		2 years
Period of extension option		1 year
Revolving credit facility, net		$ 182,800,000
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
Mortgage note and other loan payable
Interest rate (as a percent)		3.73%
Master Repurchase Agreement | Minimum | LIBOR
Mortgage note and other loan payable
Credit facility, interest rate (as a percent)		2.25%
Master Repurchase Agreement | Maximum | LIBOR
Mortgage note and other loan payable
Credit facility, interest rate (as a percent)		4.00%
Uncommitted Master Repurchase Agreements
Mortgage note and other loan payable
Number of instruments | debt_instrument		2
Uncommitted Master Repurchase Agreement, 2
Mortgage note and other loan payable
Maximum borrowing capacity		$ 300,000,000
Initial term		1 year
Revolving credit facility, net		$ (1,100,000)
919 Third Avenue
Mortgage note and other loan payable
Fixed rate debt		$ 500,000,000	500,000,000
Controlling interest in the joint venture (as a percent)		51.00%
919 Third Avenue | Weighted Average
Mortgage note and other loan payable
Interest rate (as a percent)		5.12%
315 West 33rd Street
Mortgage note and other loan payable
Fixed rate debt		$ 250,000,000	$ 0
315 West 33rd Street | Weighted Average
Mortgage note and other loan payable
Interest rate (as a percent)		4.24%

Corporate Indebtedness (Details

Corporate Indebtedness (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Corporate Indebtedness
Revolving credit facility, net		$ 275,832,000		$ 275,832,000		$ 0
Carrying value		3,197,642,000		3,197,642,000
Debt disclosures by scheduled maturity date
Accreted Balance		796,284,000		796,284,000		795,260,000
Scheduled amortization and principal repayments
Remaining 2,017		0		0
2,018		434,642,000		434,642,000
2,019		1,463,000,000		1,463,000,000
2,020		250,000,000		250,000,000
2,021		0		0
Thereafter		1,050,000,000		1,050,000,000
Total amortization of debt and principal repayments		3,197,642,000		3,197,642,000
Interest expense
Interest expense		34,658,000	$ 25,087,000	96,740,000	$ 84,175,000
Interest capitalized		(31,000)	(362,000)	(533,000)	(799,000)
Interest income		0	(2,000)	(5,000)	(9,000)
Interest expense, net		34,627,000	$ 24,723,000	96,202,000	$ 83,367,000
Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		800,000,000		800,000,000
Accreted Balance		799,934,000		799,934,000		799,880,000
Deferred financing costs, net		(3,650,000)		(3,650,000)		(4,620,000)
Total		796,284,000		796,284,000		795,260,000
Revolving credit facility
Corporate Indebtedness
Maximum borrowing capacity		1,600,000,000		1,600,000,000
Maximum borrowing capacity, optional expansion		3,000,000,000		$ 3,000,000,000
Facility fee on total commitments, payable quarterly in arrears (as a percent)				0.25%
Revolving credit facility, net		280,000,000		$ 280,000,000
Carrying value		$ 280,000,000		$ 280,000,000
Debt disclosures by scheduled maturity date
Effective Rate (as a percent)		2.49%		2.49%
Scheduled amortization and principal repayments
Remaining 2,017		$ 0		$ 0
2,018		0		0
2,019		280,000,000		280,000,000
2,020		0		0
2,021		0		0
Thereafter		0		0
Total amortization of debt and principal repayments		280,000,000		$ 280,000,000
Revolving credit facility | Minimum
Corporate Indebtedness
Facility fee on total commitments, payable quarterly in arrears (as a percent)				0.125%
Revolving credit facility | Maximum
Corporate Indebtedness
Facility fee on total commitments, payable quarterly in arrears (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
Maximum borrowing capacity		1,183,000,000		$ 1,183,000,000
Carrying value		$ 1,183,000,000		$ 1,183,000,000
Debt disclosures by scheduled maturity date
Effective Rate (as a percent)		2.63%		2.63%
Scheduled amortization and principal repayments
Remaining 2,017		$ 0		$ 0
2,018		0		0
2,019		1,183,000,000		1,183,000,000
2,020		0		0
2,021		0		0
Thereafter		0		0
Total amortization of debt and principal repayments		1,183,000,000		1,183,000,000
Term loan | Line of Credit
Corporate Indebtedness
Carrying value		1,200,000,000		1,200,000,000		1,200,000,000
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments		1,200,000,000		$ 1,200,000,000		1,200,000,000
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%
Credit Facility 2012
Corporate Indebtedness
Letters of credit		80,800,000		$ 80,800,000
Ability to borrow under line of credit facility		1,200,000,000		1,200,000,000
Credit Facility 2012 | Line of Credit
Corporate Indebtedness
Carrying value		275,800,000		275,800,000		(6,300,000)
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments		275,800,000		275,800,000		(6,300,000)
5.00% senior unsecured notes maturing on August 15, 2018 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		250,000,000		250,000,000
Accreted Balance		$ 249,934,000		$ 249,934,000		249,880,000
Coupon Rate (as a percent)		5.00%		5.00%
Effective Rate (as a percent)		5.00%		5.00%
Initial Term (in Years)				7 years
7.75% senior unsecured notes maturing on March 15, 2020 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 250,000,000		$ 250,000,000
Accreted Balance		$ 250,000,000		$ 250,000,000		250,000,000
Coupon Rate (as a percent)		7.75%		7.75%
Effective Rate (as a percent)		7.75%		7.75%
Initial Term (in Years)				10 years
4.50% senior unsecured notes maturing on December 01, 2022 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 200,000,000		$ 200,000,000
Accreted Balance		$ 200,000,000		$ 200,000,000		200,000,000
Coupon Rate (as a percent)		4.50%		4.50%
Effective Rate (as a percent)		4.50%		4.50%
Initial Term (in Years)				10 years
4.27% senior unsecured notes maturing December 17, 2025 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 100,000,000		$ 100,000,000
Accreted Balance		$ 100,000,000		$ 100,000,000		$ 100,000,000
Coupon Rate (as a percent)		4.27%		4.27%
Effective Rate (as a percent)		4.27%		4.27%
Initial Term (in Years)				10 years
Exchangeable Senior Notes Due 2017 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Coupon Rate (as a percent)		3.00%		3.00%
Mortgage and Other Loans Payable
Scheduled Amortization
Remaining 2,017		$ 0		$ 0
2,018		0		0
2,019		0		0
2,020		0		0
2,021		0		0
Thereafter		0		0
Total amortization of debt		0		0
Principal Repayments
Remaining 2,017		0		0
2,018		184,642,000		184,642,000
2,019		0		0
2,020		0		0
2,021		0		0
Thereafter		750,000,000		750,000,000
Total principal repayments		934,642,000		934,642,000
Senior Unsecured Notes
Corporate Indebtedness
Carrying value		800,000,000		800,000,000
Scheduled amortization and principal repayments
Remaining 2,017		0		0
2,018		250,000,000		250,000,000
2,019		0		0
2,020		250,000,000		250,000,000
2,021		0		0
Thereafter		300,000,000		300,000,000
Total amortization of debt and principal repayments		$ 800,000,000		$ 800,000,000
Subsequent Event | 4.50 Percent Senior Unsecured Bonds Due December 2022 [Member] | Senior Unsecured Bonds
Corporate Indebtedness
Face amount	$ 100,000,000
Redemption price, percentage	105.334%
Debt disclosures by scheduled maturity date
Coupon Rate (as a percent)	4.50%
Effective Rate (as a percent)	3.298%
Subsequent Event | 3.25 Percent Senior Unsecured Notes Due October 2022 | Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Coupon Rate (as a percent)	3.25%

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliate - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Related Party Transactions
Profit participation received by related party	$ 0.8	$ 0.8	$ 2.5	$ 2.5
Alliance Building Services
Related Party Transactions
Payments made for services	2.6	1.2	7.1	6
SL Green
Related Party Transactions
Allocation of salary and other operating costs from related party	3	2.8	9.2	8.2
Insurance expense incurred	$ 1.3	$ 1.5	$ 4.1	$ 4.4

Preferred Units (Details)

Preferred Units (Details)	9 Months Ended
	Sep. 30, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	Aug. 31, 2015shares	Jul. 22, 2015USD ($)
Class of Stock [Line Items]
Number of company common stock issued on conversion of Series B preferred units	6.71348
Series A Preferred Units
Class of Stock [Line Items]
Fair value of embedded derivative | $	$ 0	$ 0		$ 0
Partnership Interest | Series A Preferred Units
Class of Stock [Line Items]
Number of units authorized (in shares) | shares	109,161
Dividend rate, preferred units (as a percent)	3.50%
Liquidation preference of preferred units (in usd per share) | $ / shares	$ 1,000
Number of units issued (in shares) | shares			109,161
Annual dividends on preferred units (in usd per share) | $ / shares	$ 35

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value of Financial Instruments
Company's investments in unconsolidated joint ventures	$ 128,794	$ 174,127
Financing receivables included in other assets	94,800	144,500
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments, net	2,020,739	1,640,412
Fair Value
Fair Value of Financial Instruments
Estimated fair value of debt and preferred equity investments, low end of range	2,000,000	1,600,000
Estimated fair value of debt and preferred equity investments, high end of range	2,200,000	1,800,000
Level 3 | Carrying Value
Fair Value of Financial Instruments
Fixed rate debt	2,349,934	2,099,880
Variable rate debt	847,642	567,642
Total	3,197,576	2,667,522
Level 3 | Fair Value
Fair Value of Financial Instruments
Fixed rate debt	2,441,240	2,183,042
Variable rate debt	855,640	580,083
Total	3,296,880	$ 2,763,125
Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017 | Fixed Rate Investments
Fair Value of Financial Instruments
Carrying value of notes receivable	$ 250,000

Financial Instruments_ Deriva51

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative [Line Items]
Deferred net losses from terminated hedges			$ 1,300		$ 1,600
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months			400
Interest Rate Swap
Derivative [Line Items]
Amount of Gain Recognized in Other Comprehensive Loss (Effective Portion)	$ 0	$ 0	0	$ (13)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	89	90	269	521
Amount of Gain Recognized into Income (Ineffective Portion)	$ 0	$ 0	$ 0	$ 3

Commitments and Contingencies52

Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Minimum initial term of noncancellable operating leases (in years)	1 year
Non-cancellable operating leases
Remaining 2,017	$ 5,147
2,018	20,586
2,019	20,586
2,020	20,586
2,021	20,736
Thereafter	308,202
Total minimum lease payments	$ 395,843

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)segment	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Segment information
Number of reportable segments | segment			2
Total revenues	$ 241,908	$ 271,336	$ 726,075	$ 742,758
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves	64,693	102,923	219,224	250,043
Total assets	8,753,560		8,753,560		$ 8,754,613
Marketing, general and administrative	92	156	321	605
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	282	0	285	0
Depreciable real estate reserves	(379)	0	(85,707)	0
Net income	64,710	102,923	138,849	243,144
Real Estate Segment
Segment information
Total revenues	193,962	195,621	577,151	567,277
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves	24,705	27,975	87,700	82,430
Total assets	6,563,972		6,563,972		6,785,305
Debt and Preferred Equity Segment
Segment information
Total revenues	47,946	75,715	148,924	175,481
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, and depreciable real estate reserves	39,988	$ 74,948	131,524	$ 167,613
Total assets	$ 2,189,588		$ 2,189,588		$ 1,969,308