Reckson Operating Partnership 10-Q 15 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 15, 2018
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	Mar. 31, 2018
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	2,018
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Commercial real estate properties, at cost:
Land and land interests	$ 1,480,613	$ 1,704,142
Building and improvements	3,174,800	4,251,610
Building leasehold and improvements	1,073,703	1,073,703
Commercial real estate properties, gross	5,729,116	7,029,455
Less: accumulated depreciation	(1,217,640)	(1,492,603)
Total commercial real estate properties, net	4,511,476	5,536,852
Assets held for sale	67,819	67,228
Cash and cash equivalents	18,169	36,013
Restricted cash	36,667	41,117
Tenant and other receivables, net of allowance of $6,856 and $7,237 in 2018 and 2017, respectively	21,703	31,006
Deferred rents receivable, net of allowance of $10,928 and $11,189 in 2018 and 2017, respectively	184,688	233,300
Debt and preferred equity investments, net of discounts and deferred origination fees of $24,998 and $25,507 in 2018 and 2017, respectively	1,835,407	2,114,041
Investments in unconsolidated joint ventures	380,381	130,217
Deferred costs, net of accumulated amortization of $75,423 and $77,176 in 2018 and 2017, respectively	74,193	106,136
Other assets	266,667	245,598
Total assets(1)	7,397,170	8,541,508
Liabilities
Mortgages and other loans payable, net	434,268	829,648
Unsecured term loan, net	901,168	901,067
Accrued interest payable	9,350	14,999
Other liabilities	70,281	92,514
Accounts payable and accrued expenses	62,705	60,819
Related party payables	23,808	23,808
Deferred revenue	104,719	134,650
Deferred land leases payable	1,912	1,888
Dividends payable	807	807
Security deposits	39,094	39,085
Liabilities related to assets held for sale	42	42
Total liabilities(1)	1,648,154	2,099,327
Commitments and contingencies	0	0
Preferred units	109,161	109,161
Capital
General partner capital	5,614,805	6,012,134
Limited partner capital	0	0
Accumulated other comprehensive loss	0	(1,259)
Total ROP partner's capital	5,614,805	6,010,875
Noncontrolling interests in other partnerships	25,050	322,145
Total capital	5,639,855	6,333,020
Total liabilities and capital	$ 7,397,170	$ 8,541,508

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Tenant and other receivables, net of allowance of $6,856 and $7,237 in 2018 and 2017, respectively	$ 6,856	$ 7,237
Deferred rents receivable, net of allowance of $10,928 and $11,189 in 2018 and 2017, respectively	10,928	11,189
Debt and preferred equity investments, net of discounts and deferred origination fees of $24,998 and $25,507 in 2018 and 2017, respectively	24,998	25,507
Deferred costs, net of accumulated amortization of $75,423 and $77,176 in 2018 and 2017, respectively	75,423	77,176
Land and land interests	1,480,613	1,704,142
Building and improvements	3,174,800	4,251,610
Accumulated depreciation	1,217,640	1,492,603
Other assets	266,667	245,598
Real estate debt, net	434,268	829,648
Accrued interest payable	9,350	14,999
Other liabilities	70,281	92,514
Variable Interest Entity
Land and land interests	45,100	268,600
Building and improvements	200,000	1,300,000
Accumulated depreciation	17,300	319,100
Other assets	622,800	143,900
Real estate debt, net	0	494,000
Accrued interest payable	0	2,100
Other liabilities	$ 10,500	$ 48,800

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues
Rental revenue, net	$ 137,497	$ 167,972
Escalation and reimbursement	20,540	24,545
Investment income	44,496	40,554
Other income (loss)	3,696	(716)
Total revenues	206,229	232,355
Expenses
Operating expenses, including related party expenses of $5,981 and $6,529 in 2018 and 2017	34,850	41,725
Real estate taxes	32,399	38,796
Ground rent	5,023	5,235
Interest expense, net of interest income	15,189	29,467
Amortization of deferred financing costs	1,555	2,087
Depreciation and amortization	42,012	51,784
Marketing, general and administrative	122	112
Total expenses	131,150	169,206
Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves	75,079	63,149
Equity in net income from unconsolidated joint ventures	2,747	4,255
Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate	(633)	3
Purchase price and other fair value adjustments	54,860	0
Depreciable real estate reserves	0	(56,265)
Net income	132,053	11,142
Net income attributable to noncontrolling interests in other partnerships	(292)	(14)
Preferred units distributions	(955)	(953)
Net income attributable to ROP common unitholder	$ 130,806	$ 10,175

Consolidated Statements of Ope5

Consolidated Statements of Operations (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Related party expenses included in operating expenses	$ 5,981	$ 6,529

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income attributable to ROP common unitholder	$ 130,806	$ 10,175
Other comprehensive income:
Change in net unrealized gain on derivative instruments	0	90
Comprehensive income attributable to ROP common unitholder	$ 130,806	$ 10,265

Consolidated Statement of Capit

Consolidated Statement of Capital (Unaudited) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Increase (Decrease) in Partners' Capital
Beginning Balance	$ 6,333,020
Contributions	413,376
Distributions	(940,499)
Deconsolidation of partially owned entity	(297,140)
Net income	131,098
Ending Balance	5,639,855
General Partner's Capital Class A Common Units | Class A Common Units
Increase (Decrease) in Partners' Capital
Beginning Balance	6,012,134
Contributions	412,117
Distributions	(940,252)
Net income	130,806
Ending Balance	5,614,805
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	322,145
Distributions	(247)
Deconsolidation of partially owned entity	(297,140)
Net income	292
Ending Balance	25,050
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Partners' Capital
Beginning Balance	(1,259)
Contributions	1,259
Ending Balance	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating Activities
Net income	$ 132,053	$ 11,142
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	43,567	53,871
Equity in net income from unconsolidated joint ventures	(2,747)	(4,255)
Distributions of cumulative earnings from unconsolidated joint ventures	3,374	3,606
Equity in net gain (loss) on sale of interest in unconsolidated joint venture interest/real estate	633	(3)
Purchase price and other fair value adjustments	(54,860)	0
Depreciable real estate reserves	0	56,265
Deferred rents receivable	672	(3,835)
Other non-cash adjustments	(8,791)	(7,959)
Changes in operating assets and liabilities:
Tenant and other receivables	(1,188)	961
Deferred lease costs	(1,966)	(2,769)
Other assets	(35,425)	(42,414)
Accounts payable, accrued expenses and other liabilities	11,565	269
Deferred revenue and land leases payable	4,772	4,408
Net cash provided by operating activities	91,659	69,287
Investing Activities
Acquisitions of real estate properties	(226)	0
Additions to land, buildings and improvements	(36,560)	(13,086)
Investments in unconsolidated joint ventures	(18,069)	(7)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	102,493	392
Other investments	(22,033)	32,057
Origination of debt and preferred equity investments	(229,428)	(402,453)
Repayments or redemption of debt and preferred equity investments	261,641	411,969
Net cash provided by investing activities	58,270	28,872
Financing Activities
Proceeds from mortgages and other loans payable	99,074	250,000
Proceeds from revolving credit facility and senior unsecured notes	0	277,800
Repayments of revolving credit facility and senior unsecured notes	0	(277,800)
Distributions to noncontrolling interests in other partnerships	(247)	(205)
Contributions from common unitholder	412,117	625,842
Distributions to common and preferred unitholders	(683,054)	(968,601)
Deferred loan costs and capitalized lease obligation	(113)	(2,900)
Net cash used in financing activities	(172,223)	(95,864)
Net (decrease) increase in cash and cash equivalents	(22,294)	2,295
Cash, cash equivalents, and restricted cash at beginning of year	77,130	103,419
Cash, cash equivalents, and restricted cash at end of period	54,836	105,714
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Tenant improvements and capital expenditures payable	8,684	3,503
Deferred leasing payable	613	103
Transfer of assets related to assets held for sale	0	54,694
Transfer of liabilities related to assets held for sale	0	43
Removal of fully depreciated commercial real estate properties	5,704	643
Contributions from common unitholder	0	3,304
Distributions to common unitholder	258,153	0
Deconsolidation of a subsidiary	280,718	0
Cash and cash equivalents	18,169	61,410
Total cash, cash equivalents, and restricted cash	$ 77,130	$ 103,419

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2018
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 94.98% owned by SL Green Realty Corp., or SL Green, as of March 31, 2018 . 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. We are engaged in the acquisition, ownership, management and operation of commercial and residential real estate properties, principally office properties, and also own land for future development in the New York metropolitan area. As of March 31, 2018 , we owned the following interests in properties in the New York metropolitan area, primarily in midtown Manhattan. Our investments located outside of Manhattan are referred to as the Suburban properties: Location Type Number of Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office (2) 15 8,303,245 96.1 % Retail (3)(4) 5 364,816 97.6 % Development/Redevelopment 1 160,000 5.2 % Fee Interest 1 176,530 100.0 % 22 9,004,591 94.7 % Suburban Office (5) 13 2,150,400 84.6 % Retail 1 52,000 100.0 % 14 2,202,400 84.9 % Total commercial properties 36 11,206,991 92.7 % Residential: Manhattan Residential (3) — 222,855 95.5 % Total portfolio 36 11,429,846 92.8 % (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) Includes one unconsolidated joint venture property at 919 Third Avenue comprised of approximately 1,454,000 square feet. (3) As of March 31, 2018 , 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. (4) Includes two unconsolidated joint venture retail properties at 131-137 Spring Street comprised of approximately 68,342 square feet. (5) Includes the properties at 115-117 Stevens Avenue in Valhalla, New York, and 1-6 International Drive in Rye Brook, New York which are classified as held for sale at March 31, 2018 . As of March 31, 2018 , we held debt and preferred equity investments with a book value of $1.9 billion , including $0.1 billion of debt and preferred equity investments and other financing receivables that are included in balance sheet line items other than the Debt and Preferred Equity Investments line item. 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 March 31, 2018 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, 2018 . 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, 2017 . The consolidated balance sheet at December 31, 2017 has been derived from the audited financial statements as of that date but does 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	3 Months Ended
	Mar. 31, 2018
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 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. 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 impairment when a property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell. We recognized $2.4 million and $4.2 million of rental revenue for the three months ended March 31, 2018 and 2017, 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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Identified intangible assets (included in other assets): Gross amount $ 232,571 $ 276,163 Accumulated amortization (200,301 ) (236,737 ) Net (1) $ 32,270 $ 39,426 Identified intangible liabilities (included in deferred revenue): Gross amount $ 315,624 $ 496,438 Accumulated amortization (219,981 ) (366,091 ) Net (1) $ 95,643 $ 130,347 (1) As of March 31, 2018 and December 31, 2017 , $0.1 million and $0.1 million , respectively and $0.1 million and $0.1 million , 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 March 31, 2018 . Reserve for Possible Credit Losses The reserve 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 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 months ended March 31, 2018 and 2017 . Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment. 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 within general partner capital in our consolidated 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 the New York metropolitan area. 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 located in the New York metropolitan area. 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 March 31, 2018 . For the three months ended March 31, 2018 , 16.1% , 10.5% , 8.5% , 8.3% , 8.1% , 7.1% , and 5.4% of our annualized cash 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, and 711 Third Avenue, respectively. 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 February 2018, the FASB issued Accounting Standard Update (ASU) No. 2018-03, Technical Corrections and Improvements to Financial Instruments- Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. These amendments provide additional guidance related to equity securities without a readily determinable fair value, forward contracts and options purchased on those equity securities and fair value option liabilities. The guidance will be effective for the Company in the interim period beginning after June 15, 2018. The Company has not yet adopted this new guidance and does not expect it to have a material impact on the Company’s consolidated financial statements when the new standard is implemented. In August 2017, the FASB issued 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. 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 November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The guidance requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash. As a result, entities will no longer present transfers between these items on the statement of cash flows. The Company adopted the guidance on January 1, 2018 and has included the changes in restricted cash when reconciling the beginning-of-period and end-of-period total amounts on the statement of cash flows. 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 15, 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 February 2016, the FASB issued ASU No. 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. However, the presentation and disclosure in the financial statements of non-lease components such as charges to tenants for a building’s operating expenses has been updated. In January 2018, the FASB issued an exposure draft, Leases (Topic 842) Targeted Improvements, which would provide lessors with a practical expedient to not separate non-lease components from the related lease component under certain conditions. At the March 2018 Board meeting, the Board approved an amendment to the practical expedient. We anticipate the majority of our leases would qualify for the amended practical expedient. We expect this amended guidance to be finalized in 2018 and, as a result, we would adopt the practical expedient. 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 and interim periods within those fiscal years. Early adoption is permitted. The Company expects to adopt 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 through earnings, to record changes in instrument-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income, use the exit price notion when measuring an instrument’s fair value for disclosure and to separately present financial assets and liabilities by measurement category and form of instrument on the balance sheet or in the notes to the financial statements. The Company adopted the guidance effective January 1, 2018, and it had no impact 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. The Company adopted this guidance on January 1, 2018. Since the Company’s revenue is related to leasing activities, the adoption of this guidance did 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 did 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. In February 2017, the FASB issued ASU No. 2017-05 to clarify the scope of asset derecognition guidance in Subtopic 610-20, which also provided 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 adopted this guidance on January 1, 2018, and applied the modified retrospective approach. The Company elected to adopt the practical expedient under ASC 606, Revenue from Contracts with Customers, which allows an entity to apply the guidance only to contracts with non-customers that are open based on ASU 360-20, Real Estate Sales, (i.e. failed sales) as of the adoption date. The adoption had no impact on the consolidated financial statements as the Company had no open contracts based on ASC 360-20 as of December 31, 2017 .

Property Acquisitions

Property Acquisitions	3 Months Ended
	Mar. 31, 2018
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions During the three months ended March 31, 2018 , we did not acquire any properties from a third party.

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 , we entered into agreements to sell the properties at 1-6 International Drive in Rye Brook, NY for a sale price of $55.0 million and the properties at 115-117 Stevens Avenue in Valhalla, New York, for a sales price of $12.0 million . We closed on the sale of 115-117 Stevens Avenue in May 2018 . As of March 31, 2018 , 1-6 International Drive and 115-117 Stevens Avenue were classified as held for sale. In May 2018, we reached an agreement to sell the fee interest at 635 Madison Avenue for a sales price of $151 million . We expect to record a $14 million charge in connection with the sale, which will be included in depreciable real estate reserves. The transaction, subject to certain closing conditions, is expected to be completed during the third quarter of 2018. Property Dispositions We did not sell any properties to a third party during the three months ended March 31, 2018 .

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	3 Months Ended
	Mar. 31, 2018
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 for the three months ended March 31, 2018 and the twelve months ended December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Balance at beginning of period (1) $ 2,114,041 $ 1,640,412 Debt investment originations/accretion (2) 233,370 1,142,591 Preferred equity investment originations/accretion (2) 2,074 144,456 Redemptions/sales/syndications/amortization (3) (514,078 ) (813,418 ) Balance at end of period (1) $ 1,835,407 $ 2,114,041 (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 March 31, 2018 and December 31, 2017 , we held the following debt investments with an aggregate weighted average current yield of 9.19% at March 31, 2018 (in thousands): Loan Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Fixed Rate Investments: Mortgage Loan (3) $ — $ — $ 26,380 $ 26,366 February 2019 Mortgage Loan — — 201 239 August 2019 Mezzanine Loan (4a) — 1,160,000 206,230 204,005 March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,918 24,913 April 2022 Mezzanine Loan — 280,000 35,074 34,600 August 2022 Mezzanine Loan — 86,580 12,701 12,699 November 2023 Mezzanine Loan (4b) — 115,000 12,934 12,932 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 55,250 June 2027 Mortgage/Jr. Mortgage Loan (5) — — — 250,464 — Total fixed rate $ — $ 3,896,080 $ 422,188 $ 669,968 Floating Rate Investments: Mezzanine Loan (6) — 40,000 19,999 19,982 April 2018 Mezzanine Loan (6) — 75,014 23,346 34,947 April 2018 Mezzanine Loan 523 20,523 10,952 10,934 August 2018 Mortgage/Mezzanine Loan — — 19,965 19,940 August 2018 Mezzanine Loan — 65,000 14,973 14,955 August 2018 Mortgage/Mezzanine Loan — — 16,980 16,969 September 2018 Mezzanine Loan — 37,500 14,908 14,855 September 2018 Mortgage/Mezzanine Loan 391 — 23,609 23,609 October 2018 Mezzanine Loan 2,325 45,025 34,975 34,879 October 2018 Loan Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Mezzanine Loan (4c) — 85,000 15,327 15,381 December 2018 Mezzanine Loan (4d) — 65,000 14,816 14,869 December 2018 Mezzanine Loan — 33,000 26,947 26,927 December 2018 Mezzanine Loan — 175,000 59,797 59,723 December 2018 Mezzanine Loan — 45,000 12,192 12,174 January 2019 Mezzanine Loan 4,493 27,852 9,457 8,550 January 2019 Mezzanine Loan (4e)(7) 795 — 15,150 15,148 March 2019 Mezzanine Loan — 38,000 21,951 21,939 March 2019 Mezzanine Loan — 175,000 37,307 37,250 April 2019 Mezzanine Loan — 265,000 24,862 24,830 April 2019 Mortgage/Jr. Mortgage Participation Loan 24,587 208,094 74,944 71,832 August 2019 Mezzanine Loan 2,034 189,829 37,867 37,851 September 2019 Mortgage/Mezzanine Loan 22,570 — 146,517 143,919 September 2019 Mezzanine Loan — 350,000 34,773 34,737 October 2019 Mortgage/Mezzanine Loan 1,792 — 66,026 — December 2019 Mortgage/Mezzanine Loan 21,303 — 48,245 43,845 January 2020 Mezzanine Loan 1,592 568,461 77,927 75,834 January 2020 Mortgage Loan 16,038 — 83,465 — February 2020 Mezzanine Loan 5,993 294,036 48,490 — March 2020 Mezzanine Loan 6,654 35,112 11,539 11,259 July 2020 Mezzanine Loan 47,557 326,552 79,477 75,428 November 2020 Mortgage/Mezzanine Loan 40,798 — 90,789 88,989 December 2020 Mortgage/Mezzanine Loan — — 35,179 35,152 December 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,642 15,635 July 2021 Mortgage/Mezzanine Loan (8) — — — 162,553 — Mezzanine Loan (8) — — — 74,755 — Total floating rate $ 199,445 $ 3,223,998 $ 1,268,393 $ 1,299,650 Total $ 199,445 $ 7,120,078 $ 1,690,581 $ 1,969,618 (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) 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. (4) 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) $1.3 million , (b) $12.0 million , (c) $14.6 million , (d) $14.1 million , and (e) $5.1 million . (5) A non-cash capital contribution to SL Green removed these loans from our consolidated balance sheet in March 2018. (6) This loan was extended in April 2018. (7) This loan was extended in March 2018. (8) This loan was repaid in February 2018. Preferred Equity Investments As of March 31, 2018 and December 31, 2017 , we held the following preferred equity investments with an aggregate weighted average current yield of 6.97% at March 31, 2018 (in thousands): Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Preferred Equity $ — $ 272,000 $ 144,826 $ 144,423 April 2021 Total $ — $ 272,000 $ 144,826 $ 144,423 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. At March 31, 2018 and December 31, 2017 , all debt and preferred equity investments were performing in accordance with the terms of the relevant investments, with the exception of 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 3 of the Debt Investments table above. We have determined that we have one portfolio segment of financing receivables at March 31, 2018 and 2017 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 $116.2 million and $93.4 million at March 31, 2018 and December 31, 2017 , respectively. No financing receivables were 90 days past due at March 31, 2018 .

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 , none of our investments in unconsolidated joint ventures were VIEs. All of the investments below are voting interest entities. As we do not control the joint ventures listed below, we account for them under the equity method of accounting. The table below provides general information on each of our joint ventures as of March 31, 2018 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 919 Third Avenue (3) New York State Teacher's Retirement System 51.00% 51.00% 1,454,000 January 2007 $ 1,256,727 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 Mezzanine Loan (4) 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 March 31, 2018 . Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) Acquisition date and price represent the date on which the Company initially acquired an interest in the joint venture and the actual or implied gross purchase price for the joint venture on that date. Acquisition date and price are not adjusted for subsequent acquisitions or dispositions of interest. (3) In January 2018, the partnership agreement for our investment was modified resulting in the Company no longer having a controlling interest in this investment. As a result the investment was deconsolidated as of January 1, 2018. The Company recorded its non-controlling interest at fair value resulting in a $54.9 million fair value adjustment in the consolidated statement of operations. This fair value was allocated to the assets and liabilities, including identified intangibles of the property. (4) 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. The loan matures in 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 March 31, 2018 and December 31, 2017 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type March 31, 2018 December 31, 2017 Maturity Date Mezzanine Loan (1) $ 27,628 $ 26,716 July 2036 Mezzanine Loan and Preferred Equity (2) — 100,000 $ 27,628 $ 126,716 (1) 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. (2) The mezzanine loan was repaid and the preferred equity interest was redeemed in March 2018. Sale of Joint Venture Interests or Properties We did not sell any joint venture interests or properties during the three months ended March 31, 2018 . Joint Venture Mortgages and Other Loans Payable We generally finance our joint ventures with non-recourse debt. In certain cases we have provided guarantees or master leases for tenant space, which terminate upon the satisfaction of specified circumstances or repayment of the underlying loans. The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at March 31, 2018 and December 31, 2017 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) March 31, 2018 December 31, 2017 Fixed Rate Debt: 919 Third Avenue 51.00 % June 2023 5.12 % $ 500,000 $ — Floating Rate Debt: 131-137 Spring Street 20.00 % August 2020 L+ 1.55 % $ 141,000 $ 141,000 Total joint venture mortgages and other loans payable $ 641,000 $ 141,000 Deferred financing costs, net (2,585 ) (2,862 ) Total joint venture mortgages and other loans payable, net $ 638,415 $ 138,138 (1) Economic interest represents the Company's interests in the joint venture as of March 31, 2018 . Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures table above. (2) Interest rates as of March 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified. The combined balance sheets for the unconsolidated joint ventures, at March 31, 2018 and December 31, 2017 are as follows (in thousands): March 31, 2018 December 31, 2017 Assets (1) Commercial real estate property, net $ 1,318,894 $ 273,116 Debt and preferred equity investments, net 42,628 141,716 Other assets 516,579 15,735 Total assets $ 1,878,101 $ 430,567 Liabilities and members' equity (1) Mortgages and other loans payable, net $ 638,415 $ 138,138 Other liabilities 380,762 18,908 Members' equity 858,924 273,521 Total liabilities and members' equity $ 1,878,101 $ 430,567 Company's investments in unconsolidated joint ventures $ 380,381 $ 130,217 (1) The combined assets, liabilities and equity for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018. The combined statements of operations for the unconsolidated joint ventures for the three months ended March 31, 2018 and 2017 , are as follows (in thousands): Three Months Ended March 31, 2018 2017 Total revenues $ 36,246 $ 11,249 Operating expenses 6,700 211 Real estate taxes 6,748 313 Interest expense, net of interest income 6,807 825 Amortization of deferred financing costs 277 277 Depreciation and amortization 12,487 2,101 Total expenses $ 33,019 $ 3,727 Net income (1) $ 3,227 $ 7,522 Company's equity in net income from unconsolidated joint ventures (1) $ 2,747 $ 4,255 (1) The combined statements of operation and the Company's equity in net income for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018.

Mortgages and Other Loans Payab

Mortgages and Other Loans Payable	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) March 31, 2018 December 31, 2017 Fixed Rate Debt: 315 West 33rd Street February 2027 4.24 % $ 250,000 $ 250,000 919 Third Avenue (2) — 500,000 Floating Rate Debt: 2017 Master Repurchase Agreement June 2018 L+ 2.23 % $ 189,883 $ 90,809 Total mortgages and other loans payable $ 439,883 $ 840,809 Deferred financing costs, net of amortization (5,615 ) (11,161 ) Total mortgages and other loans payable, net $ 434,268 $ 829,648 (1) Interest rate as of March 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified. (2) Our investment in the property was deconsolidated as of January 1, 2018. See Note 6, "Investments in Unconsolidated Joint Ventures". At March 31, 2018 and December 31, 2017 , 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 $0.6 billion and $1.9 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 and our ability to satisfy margin calls with cash or cash equivalents. In June 2017, we entered into the 2017 MRA, with a maximum facility capacity of $300.0 million . In April 2018, we increased the maximum facility capacity to $400.0 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 March 31, 2018 , the facility had an outstanding balance of $189.5 million , net of deferred financing costs. 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 March 31, 2018 , the facility had no outstanding balance and a carrying value of $(0.6) million , representing deferred financing costs presented within other liabilities.

Corporate Indebtedness

Corporate Indebtedness	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Corporate Indebtedness	Corporate Indebtedness 2017 Credit Facility In November 2017, the Company, SL Green and the Operating Partnership entered into an amendment to the credit facility, referred to as the 2017 credit facility, that was originally entered into in November 2012, or the 2012 credit facility. The amendment resulted in the Company no longer being a borrower, and instead is providing a guarantee of the facility. The 2012 credit facility had a carrying value of $1.2 billion , net of deferred financing costs, as of the amendment date and was removed from our consolidated balance sheet and shown as a non-cash capital contribution. SL Green and the Operating Partnership remain borrowers jointly and severally obligated under the 2017 credit facility. As of March 31, 2018 , the 2017 credit facility consisted of a $1.5 billion revolving credit facility, a $1.3 billion term loan (or "Term Loan A"), and a $200.0 million term loan (or "Term Loan B") with maturity dates of March 31, 2022, March 31, 2023, and November 21, 2024, respectively. The revolving credit facility has two six -month as-of-right extension options to March 31, 2023. SL Green and the Operating Partnership also have an option, subject to customary conditions, to increase the capacity of the credit facility to $4.5 billion at any time prior to the maturity dates for the revolving credit facility and term loans without the consent of existing lenders, by obtaining additional commitments from the existing lenders and other financial institutions. As of March 31, 2018 , SL Green and the Operating Partnership had $11.8 million of outstanding letters of credit, zero drawn under the revolving credit facility and $1.5 billion outstanding under the term loan facilities, with total undrawn capacity of $1.5 billion under the 2017 credit facility. At March 31, 2018 and December 31, 2017 , the revolving credit facility had a carrying value of $(9.2) million and $30.3 million , respectively, net of deferred financing costs. The March 31, 2018 carrying value represents deferred financing costs and is presented within other liabilities. At March 31, 2018 and December 31, 2017 , the term loan facilities had a carrying value of $1.5 billion and $1.5 billion , respectively, net of deferred financing costs. The 2017 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 March 31, 2018 and December 31, 2017 , respectively, by scheduled maturity date (amounts in thousands): Issuance March 31, March 31, December 31, Coupon (1) Initial Maturity Date August 5, 2011 (2) $ 250,000 $ 249,972 $ 249,953 5.00 % 7 August 2018 March 16, 2010 (2) 250,000 250,000 250,000 7.75 % 10 March 2020 November 15, 2012 (3) 300,000 304,920 305,163 4.50 % 10 December 2022 December 17, 2015 (2) 100,000 100,000 100,000 4.27 % 10 December 2025 $ 900,000 $ 904,892 $ 905,116 Deferred financing costs, net (3,724 ) (4,049 ) $ 900,000 $ 901,168 $ 901,067 (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. (3) In October 2017, SL Green, the Operating Partnership, and ROP, as co-obligors, issued an additional $100.0 million of 4.50% senior unsecured notes due December 2022. The notes were priced at 105.334% . We provide 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. As of March 31, 2018 , the 3.25% Senior Notes due 2022 had a carrying value of $499.5 million . Restrictive Covenants The terms of the 2017 credit facility 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 March 31, 2018 and 2017 , we were in compliance with all such covenants. Principal Maturities Combined aggregate principal maturities of mortgages and other loans payable, and senior unsecured notes as of March 31, 2018 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Senior Unsecured Notes Total Remaining 2018 $ — $ — $ 250,000 $ 250,000 2019 — — — — 2020 — 189,883 250,000 439,883 2021 — — — — 2022 — — 300,000 300,000 Thereafter — 250,000 100,000 350,000 $ — $ 439,883 $ 900,000 $ 1,339,883 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended March 31, 2018 2017 Interest expense before capitalized interest $ 15,999 $ 29,851 Interest capitalized (808 ) (380 ) Interest income (2 ) (4 ) Interest expense, net $ 15,189 $ 29,467

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2018
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 the profit participation, which is included in other income on the consolidated statements of operations, was $0.8 million and $0.8 million for the three months ended March 31, 2018 and 2017, respectively. We also recorded expenses for these services, inclusive of capitalized expenses, of $2.2 million for the three months ended March 31, 2018 , for these services (excluding services provided directly to tenants), and $2.0 million for the three months ended March 31, 2017 . 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 $2.8 million for the three months ended March 31, 2018 . The amount was $3.2 million for the three months ended March 31, 2017 . Insurance We obtained insurance coverage through an insurance program administered by SL Green. In connection with this program, we incurred insurance expense of approximately $1.1 million and $1.4 million for the three months ended March 31, 2018 and 2017 , respectively. Related Party Payable to SL Green On August 22, 2016, we issued a promissory note to our parent company in the amount of $23.8 million which bears interest at an annual rate of 6.0% , compounded quarterly, and matures on August 22, 2018.

Preferred Units

Preferred Units	3 Months Ended
	Mar. 31, 2018
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 Subsidiary Series A Preferred Units, with a liquidation preference of $1,000.00 per unit. In August 2015, the Company issued 109,161 Subsidiary Series A Preferred Units in conjunction with an acquisition. The Subsidiary Series A Preferred unitholders receive annual dividends of $35.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Subsidiary Series A Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible on a one-for-one basis, into the Series B Preferred Units of limited partnership interest, or the Subsidiary Series B Preferred Units. The Subsidiary Series B Preferred Units can be converted at any time, at the option of the unitholder, into a number of common stock equal to 6.71348 shares of SL Green common stock for each Subsidiary Series B Preferred Unit. As of March 31, 2018 , no Subsidiary 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 March 31, 2018 , the carrying amount of the derivative remained at zero .

Partners' Capital

Partners' Capital	3 Months Ended
	Mar. 31, 2018
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 us either by direct ownership or by indirect ownership through our general partner, which is its wholly-owned subsidiary. Intercompany transactions between SL Green and us are generally recorded as contributions and distributions.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
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. In January 2018, the partnership agreement for our investment in 919 Third Avenue was modified resulting in the Company no longer having a controlling interest in this investment. As a result the investment was deconsolidated as of January 1, 2018. The Company recorded its non-controlling interest at fair value resulting in a $54.9 million fair value adjustment in the consolidated statement of operations. This fair value was determined using a third party valuation which primarily utilized 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. 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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,835,407 (2) $ 2,114,041 (2) Fixed rate debt $ 1,154,892 $ 1,171,017 $ 1,655,116 $ 1,715,501 Variable rate debt 189,883 191,138 90,809 92,087 $ 1,344,775 $ 1,362,155 $ 1,745,925 $ 1,807,588 (1) Amounts exclude net deferred financing costs. (2) At March 31, 2018 , debt and preferred equity investments had an estimated fair value ranging between $1.8 billion and $2.0 billion . At December 31, 2017 , debt and preferred equity investments had an estimated fair value ranging between $2.1 billion and $2.3 billion . Disclosure about fair value of financial instruments was based on pertinent information available to us as of March 31, 2018 and December 31, 2017 . 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	3 Months Ended
	Mar. 31, 2018
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 sheet 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 March 31, 2018 , 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 income, and are recognized into earnings over the term of the related senior unsecured notes. As of March 31, 2018 and December 31, 2017 , the deferred net losses from these terminated hedges, which are included in accumulated other comprehensive income relating to net unrealized loss on derivative instruments, was approximately zero and $1.3 million , respectively. 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 March 31, 2018 and 2017 , 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 March 31, Three Months Ended March 31, Three Months Ended March 31, Derivative 2018 2017 2018 2017 2018 2017 Interest Rate Swap $ — $ — Interest expense $ — $ 90 Interest expense $ — $ —

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of March 31, 2018 , 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. 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 March 31, 2018 (in thousands): Non-cancellable operating leases Remaining 2018 $ 15,440 2019 20,586 2020 20,586 2021 20,736 2022 18,580 2023 16,274 Thereafter 273,348 Total minimum lease payments $ 385,550

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information We 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 months ended March 31, 2018 and 2017 , and selected asset information as of March 31, 2018 and December 31, 2017 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Three months ended: March 31, 2018 $ 161,733 $ 44,496 $ 206,229 March 31, 2017 191,801 40,554 232,355 Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves Three months ended: March 31, 2018 $ 45,195 $ 32,631 $ 77,826 March 31, 2017 29,636 37,768 67,404 Real Estate Segment Debt and Preferred Equity Segment Total Company Total assets As of: March 31, 2018 $ 5,400,649 $ 1,996,521 $ 7,397,170 December 31, 2017 6,182,431 2,359,077 8,541,508 Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves represents total revenues less total expenses for the real estate segment and total investment income less allocated interest expense for the debt and preferred equity segment. Interest costs for the debt and preferred equity segment includes actual costs incurred for investments collateralizing the MRAs. Interest is imputed on the remaining investments using our corporate borrowing cost. We also allocate loan loss reserves, net of recoveries, and transaction related costs to the debt and preferred equity segment. We do not allocate marketing, general and administrative expenses to the debt and preferred equity segment since the use of personnel and resources is dependent on transaction volume between the two segments and varies period over period. In addition, we base performance on the individual segments excluding marketing, general and administrative expenses. All other expenses, except interest, relate entirely to the real estate assets. For the three months ended March 31, 2018 and 2017 , marketing, general and administrative expenses totaled $0.1 million and $0.1 million , respectively. There were no transactions between the above two segments. The table below reconciles income from continuing operations to net income for the three months ended March 31, 2018 and 2017 (in thousands): Three Months Ended March 31, 2018 2017 Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves $ 77,826 $ 67,404 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (633 ) 3 Purchase price and other fair value adjustments 54,860 — Depreciable real estate reserves — (56,265 ) Net income $ 132,053 $ 11,142

Significant Accounting Polici24

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
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 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. 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 impairment when a property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell.
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 reserve 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 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 months ended March 31, 2018 and 2017 . Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment.
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 within general partner capital in our consolidated 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 the New York metropolitan area. See Note 5, "Debt and Preferred Equity Investments."
Reclassification	Reclassification Certain prior year balances have been reclassified to conform to our current year presentation.
Accounting Standards Updates	Accounting Standards Updates In February 2018, the FASB issued Accounting Standard Update (ASU) No. 2018-03, Technical Corrections and Improvements to Financial Instruments- Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. These amendments provide additional guidance related to equity securities without a readily determinable fair value, forward contracts and options purchased on those equity securities and fair value option liabilities. The guidance will be effective for the Company in the interim period beginning after June 15, 2018. The Company has not yet adopted this new guidance and does not expect it to have a material impact on the Company’s consolidated financial statements when the new standard is implemented. In August 2017, the FASB issued 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. 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 November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The guidance requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash. As a result, entities will no longer present transfers between these items on the statement of cash flows. The Company adopted the guidance on January 1, 2018 and has included the changes in restricted cash when reconciling the beginning-of-period and end-of-period total amounts on the statement of cash flows. 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 15, 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 February 2016, the FASB issued ASU No. 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. However, the presentation and disclosure in the financial statements of non-lease components such as charges to tenants for a building’s operating expenses has been updated. In January 2018, the FASB issued an exposure draft, Leases (Topic 842) Targeted Improvements, which would provide lessors with a practical expedient to not separate non-lease components from the related lease component under certain conditions. At the March 2018 Board meeting, the Board approved an amendment to the practical expedient. We anticipate the majority of our leases would qualify for the amended practical expedient. We expect this amended guidance to be finalized in 2018 and, as a result, we would adopt the practical expedient. 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 and interim periods within those fiscal years. Early adoption is permitted. The Company expects to adopt 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 through earnings, to record changes in instrument-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income, use the exit price notion when measuring an instrument’s fair value for disclosure and to separately present financial assets and liabilities by measurement category and form of instrument on the balance sheet or in the notes to the financial statements. The Company adopted the guidance effective January 1, 2018, and it had no impact 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. The Company adopted this guidance on January 1, 2018. Since the Company’s revenue is related to leasing activities, the adoption of this guidance did 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 did 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. In February 2017, the FASB issued ASU No. 2017-05 to clarify the scope of asset derecognition guidance in Subtopic 610-20, which also provided 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 adopted this guidance on January 1, 2018, and applied the modified retrospective approach. The Company elected to adopt the practical expedient under ASC 606, Revenue from Contracts with Customers, which allows an entity to apply the guidance only to contracts with non-customers that are open based on ASU 360-20, Real Estate Sales, (i.e. failed sales) as of the adoption date. The adoption had no impact on the consolidated financial statements as the Company had no open contracts based on ASC 360-20 as of December 31, 2017 .
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. In January 2018, the partnership agreement for our investment in 919 Third Avenue was modified resulting in the Company no longer having a controlling interest in this investment. As a result the investment was deconsolidated as of January 1, 2018. The Company recorded its non-controlling interest at fair value resulting in a $54.9 million fair value adjustment in the consolidated statement of operations. This fair value was determined using a third party valuation which primarily utilized 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. 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)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of March 31, 2018 , we owned the following interests in properties in the New York metropolitan area, primarily in midtown Manhattan. Our investments located outside of Manhattan are referred to as the Suburban properties: Location Type Number of Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office (2) 15 8,303,245 96.1 % Retail (3)(4) 5 364,816 97.6 % Development/Redevelopment 1 160,000 5.2 % Fee Interest 1 176,530 100.0 % 22 9,004,591 94.7 % Suburban Office (5) 13 2,150,400 84.6 % Retail 1 52,000 100.0 % 14 2,202,400 84.9 % Total commercial properties 36 11,206,991 92.7 % Residential: Manhattan Residential (3) — 222,855 95.5 % Total portfolio 36 11,429,846 92.8 % (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) Includes one unconsolidated joint venture property at 919 Third Avenue comprised of approximately 1,454,000 square feet. (3) As of March 31, 2018 , 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. (4) Includes two unconsolidated joint venture retail properties at 131-137 Spring Street comprised of approximately 68,342 square feet. (5) Includes the properties at 115-117 Stevens Avenue in Valhalla, New York, and 1-6 International Drive in Rye Brook, New York which are classified as held for sale at March 31, 2018 .

Significant Accounting Polici26

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Identified intangible assets (included in other assets): Gross amount $ 232,571 $ 276,163 Accumulated amortization (200,301 ) (236,737 ) Net (1) $ 32,270 $ 39,426 Identified intangible liabilities (included in deferred revenue): Gross amount $ 315,624 $ 496,438 Accumulated amortization (219,981 ) (366,091 ) Net (1) $ 95,643 $ 130,347 (1) As of March 31, 2018 and December 31, 2017 , $0.1 million and $0.1 million , respectively and $0.1 million and $0.1 million , respectively, of net intangible assets and net intangible liabilities, were reclassified to assets held for sale and liabilities related to assets held for sale.

Debt and Preferred Equity Inv27

Debt and Preferred Equity Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of debt and preferred equity book balance roll forward	three months ended March 31, 2018 and the twelve months ended December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Balance at beginning of period (1) $ 2,114,041 $ 1,640,412 Debt investment originations/accretion (2) 233,370 1,142,591 Preferred equity investment originations/accretion (2) 2,074 144,456 Redemptions/sales/syndications/amortization (3) (514,078 ) (813,418 ) Balance at end of period (1) $ 1,835,407 $ 2,114,041 (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 March 31, 2018 and December 31, 2017 , we held the following debt investments with an aggregate weighted average current yield of 9.19% at March 31, 2018 (in thousands): Loan Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Fixed Rate Investments: Mortgage Loan (3) $ — $ — $ 26,380 $ 26,366 February 2019 Mortgage Loan — — 201 239 August 2019 Mezzanine Loan (4a) — 1,160,000 206,230 204,005 March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,918 24,913 April 2022 Mezzanine Loan — 280,000 35,074 34,600 August 2022 Mezzanine Loan — 86,580 12,701 12,699 November 2023 Mezzanine Loan (4b) — 115,000 12,934 12,932 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 55,250 June 2027 Mortgage/Jr. Mortgage Loan (5) — — — 250,464 — Total fixed rate $ — $ 3,896,080 $ 422,188 $ 669,968 Floating Rate Investments: Mezzanine Loan (6) — 40,000 19,999 19,982 April 2018 Mezzanine Loan (6) — 75,014 23,346 34,947 April 2018 Mezzanine Loan 523 20,523 10,952 10,934 August 2018 Mortgage/Mezzanine Loan — — 19,965 19,940 August 2018 Mezzanine Loan — 65,000 14,973 14,955 August 2018 Mortgage/Mezzanine Loan — — 16,980 16,969 September 2018 Mezzanine Loan — 37,500 14,908 14,855 September 2018 Mortgage/Mezzanine Loan 391 — 23,609 23,609 October 2018 Mezzanine Loan 2,325 45,025 34,975 34,879 October 2018 Loan Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Mezzanine Loan (4c) — 85,000 15,327 15,381 December 2018 Mezzanine Loan (4d) — 65,000 14,816 14,869 December 2018 Mezzanine Loan — 33,000 26,947 26,927 December 2018 Mezzanine Loan — 175,000 59,797 59,723 December 2018 Mezzanine Loan — 45,000 12,192 12,174 January 2019 Mezzanine Loan 4,493 27,852 9,457 8,550 January 2019 Mezzanine Loan (4e)(7) 795 — 15,150 15,148 March 2019 Mezzanine Loan — 38,000 21,951 21,939 March 2019 Mezzanine Loan — 175,000 37,307 37,250 April 2019 Mezzanine Loan — 265,000 24,862 24,830 April 2019 Mortgage/Jr. Mortgage Participation Loan 24,587 208,094 74,944 71,832 August 2019 Mezzanine Loan 2,034 189,829 37,867 37,851 September 2019 Mortgage/Mezzanine Loan 22,570 — 146,517 143,919 September 2019 Mezzanine Loan — 350,000 34,773 34,737 October 2019 Mortgage/Mezzanine Loan 1,792 — 66,026 — December 2019 Mortgage/Mezzanine Loan 21,303 — 48,245 43,845 January 2020 Mezzanine Loan 1,592 568,461 77,927 75,834 January 2020 Mortgage Loan 16,038 — 83,465 — February 2020 Mezzanine Loan 5,993 294,036 48,490 — March 2020 Mezzanine Loan 6,654 35,112 11,539 11,259 July 2020 Mezzanine Loan 47,557 326,552 79,477 75,428 November 2020 Mortgage/Mezzanine Loan 40,798 — 90,789 88,989 December 2020 Mortgage/Mezzanine Loan — — 35,179 35,152 December 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,642 15,635 July 2021 Mortgage/Mezzanine Loan (8) — — — 162,553 — Mezzanine Loan (8) — — — 74,755 — Total floating rate $ 199,445 $ 3,223,998 $ 1,268,393 $ 1,299,650 Total $ 199,445 $ 7,120,078 $ 1,690,581 $ 1,969,618 (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) 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. (4) 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) $1.3 million , (b) $12.0 million , (c) $14.6 million , (d) $14.1 million , and (e) $5.1 million . (5) A non-cash capital contribution to SL Green removed these loans from our consolidated balance sheet in March 2018. (6) This loan was extended in April 2018. (7) This loan was extended in March 2018. (8) This loan was repaid in February 2018.
Schedule of preferred equity investments	As of March 31, 2018 and December 31, 2017 , we held the following preferred equity investments with an aggregate weighted average current yield of 6.97% at March 31, 2018 (in thousands): Type March 31, 2018 March 31, 2018 Senior March 31, 2018 (1) December 31, 2017 (1) Maturity (2) Preferred Equity $ — $ 272,000 $ 144,826 $ 144,423 April 2021 Total $ — $ 272,000 $ 144,826 $ 144,423

Investments in Unconsolidated28

Investments in Unconsolidated Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Schedule of general information on joint ventures	The table below provides general information on each of our joint ventures as of March 31, 2018 : Property Partner Ownership Interest (1) Economic Interest (1) Unaudited Approximate Square Feet Acquisition Date (2) Acquisition Price (2) (in thousands) 919 Third Avenue (3) New York State Teacher's Retirement System 51.00% 51.00% 1,454,000 January 2007 $ 1,256,727 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 Mezzanine Loan (4) 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 March 31, 2018 . Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) Acquisition date and price represent the date on which the Company initially acquired an interest in the joint venture and the actual or implied gross purchase price for the joint venture on that date. Acquisition date and price are not adjusted for subsequent acquisitions or dispositions of interest. (3) In January 2018, the partnership agreement for our investment was modified resulting in the Company no longer having a controlling interest in this investment. As a result the investment was deconsolidated as of January 1, 2018. The Company recorded its non-controlling interest at fair value resulting in a $54.9 million fair value adjustment in the consolidated statement of operations. This fair value was allocated to the assets and liabilities, including identified intangibles of the property. (4) 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. The loan matures in November 2018. As of March 31, 2018 and December 31, 2017 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type March 31, 2018 December 31, 2017 Maturity Date Mezzanine Loan (1) $ 27,628 $ 26,716 July 2036 Mezzanine Loan and Preferred Equity (2) — 100,000 $ 27,628 $ 126,716 (1) 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. (2) The mezzanine loan was repaid and the preferred equity interest was redeemed in March 2018.
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 March 31, 2018 and December 31, 2017 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) March 31, 2018 December 31, 2017 Fixed Rate Debt: 919 Third Avenue 51.00 % June 2023 5.12 % $ 500,000 $ — Floating Rate Debt: 131-137 Spring Street 20.00 % August 2020 L+ 1.55 % $ 141,000 $ 141,000 Total joint venture mortgages and other loans payable $ 641,000 $ 141,000 Deferred financing costs, net (2,585 ) (2,862 ) Total joint venture mortgages and other loans payable, net $ 638,415 $ 138,138 (1) Economic interest represents the Company's interests in the joint venture as of March 31, 2018 . Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures table above. (2) Interest rates as of March 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified.
Schedule of combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at March 31, 2018 and December 31, 2017 are as follows (in thousands): March 31, 2018 December 31, 2017 Assets (1) Commercial real estate property, net $ 1,318,894 $ 273,116 Debt and preferred equity investments, net 42,628 141,716 Other assets 516,579 15,735 Total assets $ 1,878,101 $ 430,567 Liabilities and members' equity (1) Mortgages and other loans payable, net $ 638,415 $ 138,138 Other liabilities 380,762 18,908 Members' equity 858,924 273,521 Total liabilities and members' equity $ 1,878,101 $ 430,567 Company's investments in unconsolidated joint ventures $ 380,381 $ 130,217 (1) The combined assets, liabilities and equity for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018.
Schedule of combined statements of operations for the unconsolidated joint ventures	March 31, 2018 December 31, 2017 Assets (1) Commercial real estate property, net $ 1,318,894 $ 273,116 Debt and preferred equity investments, net 42,628 141,716 Other assets 516,579 15,735 Total assets $ 1,878,101 $ 430,567 Liabilities and members' equity (1) Mortgages and other loans payable, net $ 638,415 $ 138,138 Other liabilities 380,762 18,908 Members' equity 858,924 273,521 Total liabilities and members' equity $ 1,878,101 $ 430,567 Company's investments in unconsolidated joint ventures $ 380,381 $ 130,217 (1) The combined assets, liabilities and equity for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018. The combined statements of operations for the unconsolidated joint ventures for the three months ended March 31, 2018 and 2017 , are as follows (in thousands): Three Months Ended March 31, 2018 2017 Total revenues $ 36,246 $ 11,249 Operating expenses 6,700 211 Real estate taxes 6,748 313 Interest expense, net of interest income 6,807 825 Amortization of deferred financing costs 277 277 Depreciation and amortization 12,487 2,101 Total expenses $ 33,019 $ 3,727 Net income (1) $ 3,227 $ 7,522 Company's equity in net income from unconsolidated joint ventures (1) $ 2,747 $ 4,255 (1) The combined statements of operation and the Company's equity in net income for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018.

Mortgages and Other Loans Pay29

Mortgages and Other Loans Payable (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) March 31, 2018 December 31, 2017 Fixed Rate Debt: 315 West 33rd Street February 2027 4.24 % $ 250,000 $ 250,000 919 Third Avenue (2) — 500,000 Floating Rate Debt: 2017 Master Repurchase Agreement June 2018 L+ 2.23 % $ 189,883 $ 90,809 Total mortgages and other loans payable $ 439,883 $ 840,809 Deferred financing costs, net of amortization (5,615 ) (11,161 ) Total mortgages and other loans payable, net $ 434,268 $ 829,648 (1) Interest rate as of March 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified. (2) Our investment in the property was deconsolidated as of January 1, 2018. See Note 6, "Investments in Unconsolidated Joint Ventures".

Corporate Indebtedness (Tables)

Corporate Indebtedness (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 , respectively, by scheduled maturity date (amounts in thousands): Issuance March 31, March 31, December 31, Coupon (1) Initial Maturity Date August 5, 2011 (2) $ 250,000 $ 249,972 $ 249,953 5.00 % 7 August 2018 March 16, 2010 (2) 250,000 250,000 250,000 7.75 % 10 March 2020 November 15, 2012 (3) 300,000 304,920 305,163 4.50 % 10 December 2022 December 17, 2015 (2) 100,000 100,000 100,000 4.27 % 10 December 2025 $ 900,000 $ 904,892 $ 905,116 Deferred financing costs, net (3,724 ) (4,049 ) $ 900,000 $ 901,168 $ 901,067 (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. (3) In October 2017, SL Green, the Operating Partnership, and ROP, as co-obligors, issued an additional $100.0 million of 4.50% senior unsecured notes due December 2022. The notes were priced at 105.334%
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, and senior unsecured notes as of March 31, 2018 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Senior Unsecured Notes Total Remaining 2018 $ — $ — $ 250,000 $ 250,000 2019 — — — — 2020 — 189,883 250,000 439,883 2021 — — — — 2022 — — 300,000 300,000 Thereafter — 250,000 100,000 350,000 $ — $ 439,883 $ 900,000 $ 1,339,883
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended March 31, 2018 2017 Interest expense before capitalized interest $ 15,999 $ 29,851 Interest capitalized (808 ) (380 ) Interest income (2 ) (4 ) Interest expense, net $ 15,189 $ 29,467

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,835,407 (2) $ 2,114,041 (2) Fixed rate debt $ 1,154,892 $ 1,171,017 $ 1,655,116 $ 1,715,501 Variable rate debt 189,883 191,138 90,809 92,087 $ 1,344,775 $ 1,362,155 $ 1,745,925 $ 1,807,588 (1) Amounts exclude net deferred financing costs. (2) At March 31, 2018 , debt and preferred equity investments had an estimated fair value ranging between $1.8 billion and $2.0 billion . At December 31, 2017 , debt and preferred equity investments had an estimated fair value ranging between $2.1 billion and $2.3 billion .

Financial Instruments_ Deriva32

Financial Instruments: Derivatives and Hedging (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 and 2017 , 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 March 31, Three Months Ended March 31, Three Months Ended March 31, Derivative 2018 2017 2018 2017 2018 2017 Interest Rate Swap $ — $ — Interest expense $ — $ 90 Interest expense $ — $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
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 March 31, 2018 (in thousands): Non-cancellable operating leases Remaining 2018 $ 15,440 2019 20,586 2020 20,586 2021 20,736 2022 18,580 2023 16,274 Thereafter 273,348 Total minimum lease payments $ 385,550

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected consolidated results of operations for the three months ended March 31, 2018 and 2017 , and selected asset information as of March 31, 2018 and December 31, 2017 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Three months ended: March 31, 2018 $ 161,733 $ 44,496 $ 206,229 March 31, 2017 191,801 40,554 232,355 Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves Three months ended: March 31, 2018 $ 45,195 $ 32,631 $ 77,826 March 31, 2017 29,636 37,768 67,404 Real Estate Segment Debt and Preferred Equity Segment Total Company Total assets As of: March 31, 2018 $ 5,400,649 $ 1,996,521 $ 7,397,170 December 31, 2017 6,182,431 2,359,077 8,541,508
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 months ended March 31, 2018 and 2017 (in thousands): Three Months Ended March 31, 2018 2017 Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves $ 77,826 $ 67,404 Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate (633 ) 3 Purchase price and other fair value adjustments 54,860 — Depreciable real estate reserves — (56,265 ) Net income $ 132,053 $ 11,142

Organization and Basis of Pre35

Organization and Basis of Presentation (Details) $ in Billions	3 Months Ended
	Mar. 31, 2018USD ($)ft²property
Real estate properties
Percentage of ownership in SL Green Operating Partnership owned by SL Green Realty Corp (as a percent)	94.98%
Number of Properties | property	36
Approximate Square Feet (sqft)	11,429,846
Weighted Average Occupancy (as a percent)	92.80%
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $	$ 1.9
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)	94.70%
Suburban
Real estate properties
Number of Properties | property	14
Approximate Square Feet (sqft)	2,202,400
Weighted Average Occupancy (as a percent)	84.90%
Office | Manhattan
Real estate properties
Number of Properties | property	15
Approximate Square Feet (sqft)	8,303,245
Weighted Average Occupancy (as a percent)	96.10%
Office | Suburban
Real estate properties
Number of Properties | property	13
Approximate Square Feet (sqft)	2,150,400
Weighted Average Occupancy (as a percent)	84.60%
Retail | 919 Third Avenue
Real estate properties
Approximate Square Feet (sqft)	1,454,000
Number of unconsolidated joint venture properties | property	1
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)	97.60%
Retail | Suburban
Real estate properties
Number of Properties | property	1
Approximate Square Feet (sqft)	52,000
Weighted Average Occupancy (as a percent)	100.00%
Development Properties | Manhattan
Real estate properties
Number of Properties | property	1
Approximate Square Feet (sqft)	160,000
Weighted Average Occupancy (as a percent)	5.20%
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	36
Approximate Square Feet (sqft)	11,206,991
Weighted Average Occupancy (as a percent)	92.70%
Residential | Manhattan
Real estate properties
Number of Properties | property	0
Approximate Square Feet (sqft)	222,855
Weighted Average Occupancy (as a percent)	95.50%
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 Polici36

Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Investment in Commercial Real Estate Properties
Depreciable real estate reserves	$ 0	$ (56,265)
Increase in rental revenue from amortization of acquired leases	2,400	$ 4,200
Identified intangible assets (included in other assets):
Gross amount	232,571		$ 276,163
Accumulated amortization	(200,301)		(236,737)
Net	32,270		39,426
Identified intangible liabilities (included in deferred revenue):
Gross amount	315,624		496,438
Accumulated amortization	(219,981)		(366,091)
Net	95,643		130,347
Net Intangible Assets Transferred to Assets Held for Sale	100		100
Net Intangible Liabilities Transferred to Liabilities Related to Assets Held for Sale	$ 100		$ 100
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

Significant Accounting Polici37

Significant Accounting Policies - Concentrations of Credit Risk/Reclassification (Details) - Annualized cash rent - Customer concentration	3 Months Ended
	Mar. 31, 2018
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	16.10%
625 Madison Avenue
Concentrations of Credit Risk
Percentage of concentration	10.50%
919 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	8.50%
750 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	8.30%
810 Seventh Avenue
Concentrations of Credit Risk
Percentage of concentration	8.10%
555 W. 57th Street
Concentrations of Credit Risk
Percentage of concentration	7.10%
125 Park Avenue
Concentrations of Credit Risk
Percentage of concentration	5.40%

Properties Held for Sale and 38

Properties Held for Sale and Property Dispositions (Details) - USD ($) $ in Millions	May 09, 2018	Mar. 31, 2018
1-6 International Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales price		$ 55
Stevens Avenue, 115 to 117
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales price		$ 12
Subsequent Event | Madison Avenue 635 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales price	$ 151
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down	$ 14

Debt and Preferred Equity Inv39

Debt and Preferred Equity Investments - Debt and Preferred Equity Investment Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at beginning of period	$ 2,114,041	$ 1,640,412
Redemptions/Sales/Syndications/Amortization	(514,078)	(813,418)
Balance at end of period	1,835,407	2,114,041
Debt Investments in Mortgage Loans
Movement in Mortgage Loans on Real Estate [Roll Forward]
Originations/Accretion	233,370	1,142,591
Preferred Equity Investments in Mortgage Loans
Movement in Mortgage Loans on Real Estate [Roll Forward]
Originations/Accretion	$ 2,074	$ 144,456

Debt and Preferred Equity Inv40

Debt and Preferred Equity Investments (Details)	3 Months Ended
	Mar. 31, 2018USD ($)segment	Mar. 31, 2017segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2014USD ($)	Sep. 24, 2014USD ($)
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	9.19%
Debt Investments Held [Abstract]
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 1,835,407,000		$ 2,114,041,000
Number of portfolio segments | segment	1	1
Financing receivables included in other assets	$ 116,200,000		93,400,000
Mezzanine Loan with an Initial Maturity Date of March 2020
Debt Investments Held [Abstract]
Amount participated out	1,300,000
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
Debt Investments in Mortgage Loans
Debt Investments Held [Abstract]
Future Funding Obligations	199,445,000
Senior Financing	7,120,078,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 1,690,581,000		1,969,618,000
Preferred Equity Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	6.97%
Debt Investments Held [Abstract]
Future Funding Obligations	$ 0
Senior Financing	272,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	144,826,000		144,423,000
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	144,826,000		144,423,000
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	3,896,080,000
Carrying Value, Net of Discounts and Deferred Origination Fees	422,188,000		669,968,000
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	0		250,464,000
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	26,380,000		26,366,000
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	201,000		239,000
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	206,230,000		204,005,000
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	24,918,000		24,913,000
Fixed Rate Investments | Mezzanine Loan, with an Initial Maturity Date of November 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	86,580,000
Carrying Value, Net of Discounts and Deferred Origination Fees	12,701,000		12,699,000
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	12,934,000		12,932,000
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		55,250,000
Fixed Rate Investments | Mezzanine Loan with an Initial Maturity of August 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	280,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	35,074,000		34,600,000
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	199,445,000
Senior Financing	3,223,998,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	1,268,393,000		1,299,650,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of March 2020
Debt Investments Held [Abstract]
Future Funding Obligations	5,993,000
Senior Financing	294,036,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	48,490,000		0
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	19,999,000		19,982,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of April 2018, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	75,014,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	23,346,000		34,947,000
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	10,952,000		10,934,000
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	19,965,000		19,940,000
Floating Rate Investments | Mezzanine Loan With An Initial Maturity Date of August 2018, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	14,973,000		14,955,000
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	16,980,000		16,969,000
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	14,908,000		14,855,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of October 2018
Debt Investments Held [Abstract]
Future Funding Obligations	391,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	23,609,000		23,609,000
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	34,975,000		34,879,000
Floating Rate Investments | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	15,327,000		15,381,000
Floating Rate Investments | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	14,816,000		14,869,000
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	26,947,000		26,927,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	175,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	59,797,000		59,723,000
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	12,192,000		12,174,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	4,493,000
Senior Financing	27,852,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	9,457,000		8,550,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of March 2019
Debt Investments Held [Abstract]
Future Funding Obligations	795,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	15,150,000		15,148,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of March 2019, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	21,951,000		21,939,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity Date of April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	175,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	37,307,000		37,250,000
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	24,862,000		24,830,000
Floating Rate Investments | Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	24,587,000
Senior Financing	208,094,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	74,944,000		71,832,000
Floating Rate Investments | Mezzanine Loan, Maturity of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	2,034,000
Senior Financing	189,829,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	37,867,000		37,851,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	22,570,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	146,517,000		143,919,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of October 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	350,000,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	34,773,000		34,737,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2019
Debt Investments Held [Abstract]
Future Funding Obligations	1,792,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	66,026,000		0
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	21,303,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	48,245,000		43,845,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	1,592,000
Senior Financing	568,461,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	77,927,000		75,834,000
Floating Rate Investments | Mortgage Loan with an Initial Maturity of February 2020
Debt Investments Held [Abstract]
Future Funding Obligations	16,038,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	83,465,000		0
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of July 2020
Debt Investments Held [Abstract]
Future Funding Obligations	6,654,000
Senior Financing	35,112,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	11,539,000		11,259,000
Floating Rate Investments | Mezzanine Loan with an Initial Maturity of November 2020
Debt Investments Held [Abstract]
Future Funding Obligations	47,557,000
Senior Financing	326,552,000
Mortgage Loans on Real Estate, Commercial and Consumer, Net	79,477,000		75,428,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of December 2020
Debt Investments Held [Abstract]
Future Funding Obligations	40,798,000
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	90,789,000		88,989,000
Floating Rate Investments | Mortgage/Mezzanine Loan with an Initial Maturity of December 2020, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	35,179,000		35,152,000
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	15,642,000		15,635,000
Floating Rate Investments | Mortgage/Mezzanine Loan repaid in February 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	0		162,553,000
Floating Rate Investments | Mezzanine Loan repaid in February 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Mortgage Loans on Real Estate, Commercial and Consumer, Net	$ 0		$ 74,755,000

Investments in Unconsolidated41

Investments in Unconsolidated Joint Ventures - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended
	May 31, 2017USD ($)	Mar. 31, 2018USD ($)ft²	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Schedule of Equity Method Investments [Line Items]
Unaudited Approximate Square Feet (sqft) | ft²		11,429,846
Purchase price and other fair value adjustments		$ 54,860	$ 0
Acquisition, development and construction arrangements, carrying value		27,628		$ 126,716
Mezzanine Loan
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)	33.33%
Equity method investment, amount sold	$ 10,000
Mezzanine Loan Due July 2036
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value		27,628		26,716
Mezzanine Loans And Preferred Equity
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value		$ 0		$ 100,000
Joint Venture | Mezzanine Loan
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)		33.33%
Economic Interest (as a percent)		33.33%
Unaudited Approximate Square Feet (sqft) | ft²		0
Acquisition Price		$ 15,000
Joint Venture | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Ownership Interest (as a percent)		51.00%
Economic Interest (as a percent)		51.00%
Unaudited Approximate Square Feet (sqft) | ft²		1,454,000
Acquisition Price		$ 1,256,727
Joint Venture | 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
Joint Venture | 919 Third Avenue | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Purchase price and other fair value adjustments		$ 54,900

- Mortgages and Loans Payable (

- Mortgages and Loans Payable (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Fixed rate debt	$ 0	$ 500,000
Joint Venture
Schedule of Equity Method Investments [Line Items]
Total joint venture mortgages and other loans payable	641,000	141,000
Deferred financing costs, net	(2,585)	(2,862)
Total joint venture mortgages and other loans payable, net	$ 638,415	138,138
Joint Venture | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Economic Interest (as a percent)	51.00%
Interest rate (as a percent)	5.12%
Fixed rate debt	$ 500,000	0
Joint Venture | 131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Economic Interest (as a percent)	20.00%
Floating rate debt	$ 141,000	$ 141,000
Joint Venture | Weighted Average | 131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Interest rate (as a percent)	1.55%

Investments in Unconsolidated43

Investments in Unconsolidated Joint Ventures - Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Assets
Commercial real estate property, net	$ 4,511,476		$ 5,536,852
Other assets	266,667		245,598
Liabilities and members' equity
Mortgages and other loans payable, net	434,268		829,648
Other liabilities	70,281		92,514
Company's investments in unconsolidated joint ventures	380,381		130,217
Combined statements of income for the unconsolidated joint ventures
Real estate taxes	32,399	$ 38,796
Amortization of deferred financing costs	1,555	2,087
Depreciation and amortization	42,012	51,784
Total expenses	131,150	169,206
Company's equity in net income from unconsolidated joint ventures (1)	2,747	4,255
Joint Venture
Assets
Commercial real estate property, net	1,318,894		273,116
Debt and preferred equity investments, net	42,628		141,716
Other assets	516,579		15,735
Total assets	1,878,101		430,567
Liabilities and members' equity
Mortgages and other loans payable, net	638,415		138,138
Other liabilities	380,762		18,908
Members' equity	858,924		273,521
Total liabilities and members' equity	1,878,101		430,567
Company's investments in unconsolidated joint ventures	380,381		$ 130,217
Combined statements of income for the unconsolidated joint ventures
Total revenues	36,246	11,249
Operating expenses	6,700	211
Real estate taxes	6,748	313
Interest expense, net of interest income	6,807	825
Amortization of deferred financing costs	277	277
Depreciation and amortization	12,487	2,101
Total expenses	33,019	3,727
Net income (1)	3,227	7,522
Company's equity in net income from unconsolidated joint ventures (1)	$ 2,747	$ 4,255

Mortgages and Other Loans Pay44

Mortgages and Other Loans Payable (Details)	Dec. 06, 2015USD ($)	Mar. 31, 2018USD ($)debt_instrumentextension	Apr. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Jul. 31, 2016USD ($)
Mortgage note and other loan payable
Total mortgages and other loans payable		$ 439,883,000		$ 840,809,000
Deferred financing costs, net of amortization		(5,615,000)		(11,161,000)
Total mortgages and other loans payable, net		434,268,000		829,648,000
Debt and preferred equity investments		$ 600,000,000		1,900,000,000
Uncommitted Master Repurchase Agreements
Mortgage note and other loan payable
Number of instruments | debt_instrument		2
Uncommitted Master Repurchase Agreement 2017
Mortgage note and other loan payable
Floating rate debt		$ 189,883,000		90,809,000
Maximum borrowing capacity		$ 300,000,000
Initial term		1 year
Number of extension options | extension		2
Period of extension option		1 year
Revolving credit facility, net		$ 189,500,000
Uncommitted Master Repurchase Agreement 2017 | Weighted Average
Mortgage note and other loan payable
Interest rate (as a percent)		2.23%
Uncommitted Master Repurchase Agreement 2016
Mortgage note and other loan payable
Maximum borrowing capacity					$ 300,000,000
Initial term		2 years
Period of extension option		1 year
Revolving credit facility, net		$ (600,000)
Basis point fee (as a percent)	0.25%
Threshold amount for basis point fee to be applicable (less than)	$ 150,000,000
315 West 33rd Street
Mortgage note and other loan payable
Fixed rate debt		$ 250,000,000		250,000,000
315 West 33rd Street | Weighted Average
Mortgage note and other loan payable
Interest rate (as a percent)		4.24%
919 Third Avenue
Mortgage note and other loan payable
Fixed rate debt		$ 0		$ 500,000,000
Subsequent Event | Uncommitted Master Repurchase Agreement 2017
Mortgage note and other loan payable
Maximum borrowing capacity			$ 400,000,000
London Interbank Offered Rate (LIBOR) | Uncommitted Master Repurchase Agreement 2016 | Minimum
Mortgage note and other loan payable
Credit facility, interest rate (as a percent)		2.25%
London Interbank Offered Rate (LIBOR) | Uncommitted Master Repurchase Agreement 2016 | Maximum
Mortgage note and other loan payable
Credit facility, interest rate (as a percent)		4.00%

Corporate Indebtedness (Details

Corporate Indebtedness (Details)	1 Months Ended	3 Months Ended
	Oct. 31, 2017USD ($)	Mar. 31, 2018USD ($)extension	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Corporate Indebtedness
Carrying value		$ 1,339,883,000
Debt disclosures by scheduled maturity date
Accreted Balance		901,168,000		$ 901,067,000
Scheduled amortization and principal repayments
Remaining 2,018		250,000,000
2,019		0
2,020		439,883,000
2,021		0
2,022		300,000,000
Thereafter		350,000,000
Total amortization of debt and principal repayments		1,339,883,000
Interest expense
Interest expense		15,999,000	$ 29,851,000
Interest capitalized		(808,000)	(380,000)
Interest income		(2,000)	(4,000)
Interest expense, net		15,189,000	$ 29,467,000
Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		900,000,000
Accreted Balance		904,892,000		905,116,000
Deferred financing costs, net		(3,724,000)		(4,049,000)
Total		901,168,000		901,067,000
Term Loan B, Maturity November 21, 2024 | Term loan
Corporate Indebtedness
Maximum borrowing capacity		200,000,000
Term Loan A, Maturity March 31, 2023 | Term loan
Corporate Indebtedness
Maximum borrowing capacity		1,300,000,000
Revolving credit facility
Corporate Indebtedness
Revolving credit facility, net		0
Term loan
Corporate Indebtedness
Maximum borrowing capacity		1,500,000,000
Term loan | Line of Credit
Corporate Indebtedness
Carrying value		1,500,000,000		1,500,000,000
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments		1,500,000,000		1,500,000,000
4.50% Senior Unsecured Bonds Due December 2022 | 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%
Credit Facility 2012
Corporate Indebtedness
Letters of credit		11,800,000
Ability to borrow under line of credit facility		1,500,000,000
Credit Facility 2012 | Line of Credit
Corporate Indebtedness
Carrying value		(9,200,000)		30,300,000
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments		(9,200,000)		30,300,000
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
Accreted Balance		$ 249,972,000		249,953,000
Coupon Rate (as a percent)		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
Accreted Balance		$ 250,000,000		250,000,000
Coupon Rate (as a percent)		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		$ 300,000,000
Accreted Balance		$ 304,920,000		305,163,000
Coupon Rate (as a percent)		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
Accreted Balance		$ 100,000,000		$ 100,000,000
Coupon Rate (as a percent)		4.27%
Initial Term (in Years)		10 years
Mortgage and Other Loans Payable
Scheduled Amortization
Remaining 2,018		$ 0
2,019		0
2,020		0
2,021		0
2,022		0
Thereafter		0
Total amortization of debt		0
Principal Repayments
Remaining 2,018		0
2,019		0
2,020		189,883,000
2,021		0
2,022		0
Thereafter		250,000,000
Total principal repayments		439,883,000
Senior Unsecured Notes
Corporate Indebtedness
Carrying value		900,000,000
Scheduled amortization and principal repayments
Remaining 2,018		250,000,000
2,019		0
2,020		250,000,000
2,021		0
2,022		300,000,000
Thereafter		100,000,000
Total amortization of debt and principal repayments		900,000,000
3.25 Percent Senior Unsecured Notes Due October 2022 | Senior Unsecured Notes
Corporate Indebtedness
Carrying value		$ 499,500,000
Debt disclosures by scheduled maturity date
Coupon Rate (as a percent)		3.25%
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments		$ 499,500,000
Revolving credit facility | Revolving Credit Facility, Maturity March 31, 2022 | Line of Credit
Corporate Indebtedness
Maximum borrowing capacity		$ 1,500,000,000
Number of extensions | extension		2
Term of extension		6 months
Maximum borrowing capacity, optional expansion		$ 4,500,000,000
Revolving credit facility | Credit Facility 2012
Corporate Indebtedness
Maximum borrowing capacity		$ 1,200,000,000

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliate - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Aug. 22, 2016
Related Party Transactions
Profit participation received by related party	$ 0.8	$ 0.8
Alliance Building Services
Related Party Transactions
Payments made for services	2.2	2
SL Green
Related Party Transactions
Allocation of salary and other operating costs from related party	2.8	3.2
Insurance expense incurred	$ 1.1	$ 1.4
Notes payable, related parties			$ 23.8
Interest rate			6.00%

Preferred Units (Details)

Preferred Units (Details)	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares	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
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	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Fair Value of Financial Instruments
Purchase price and other fair value adjustments	$ 54,860	$ 0
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments, net	1,835,407		$ 2,114,041
Fair Value
Fair Value of Financial Instruments
Estimated fair value of debt and preferred equity investments, low end of range	1,800,000		2,100,000
Estimated fair value of debt and preferred equity investments, high end of range	2,000,000		2,300,000
Level 3 | Carrying Value
Fair Value of Financial Instruments
Fixed rate debt	1,154,892		1,655,116
Variable rate debt	189,883		90,809
Total	1,344,775		1,745,925
Level 3 | Fair Value
Fair Value of Financial Instruments
Fixed rate debt	1,171,017		1,715,501
Variable rate debt	191,138		92,087
Total	1,362,155		1,807,588
Joint Venture
Fair Value of Financial Instruments
Debt and preferred equity investments, net	42,628		$ 141,716
Joint Venture | 919 Third Avenue | 919 Third Avenue
Fair Value of Financial Instruments
Purchase price and other fair value adjustments	$ 54,900

Financial Instruments_ Deriva49

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative [Line Items]
Deferred net losses from terminated hedges	$ 0	$ 1,300
Interest Rate Swap
Derivative [Line Items]
Amount of Loss Recognized in Other Comprehensive Loss (Effective Portion)	0	0
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	0	90
Amount of Gain Recognized into Income (Ineffective Portion)	$ 0	$ 0

Commitments and Contingencies50

Commitments and Contingencies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Minimum initial term of noncancellable operating leases (in years)	1 year
Non-cancellable operating leases
Remaining 2,018	$ 15,440
2,019	20,586
2,020	20,586
2,021	20,736
2,022	18,580
2,023	16,274
Thereafter	273,348
Total minimum lease payments	$ 385,550

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)segment	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Segment information
Number of reportable segments | segment	2
Total revenues	$ 206,229	$ 232,355
Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves	77,826	67,404
Total assets	7,397,170		$ 8,541,508
Marketing, general and administrative	122	112
Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate	(633)	3
Purchase price and other fair value adjustments	54,860	0
Net income	132,053	11,142
Real Estate Segment
Segment information
Total revenues	161,733	191,801
Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves	45,195	29,636
Total assets	5,400,649		6,182,431
Debt and Preferred Equity Segment
Segment information
Total revenues	44,496	40,554
Income before equity in net income from unconsolidated joint ventures, equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate, purchase price and other fair value adjustments, and depreciable real estate reserves	32,631	$ 37,768
Total assets	$ 1,996,521		$ 2,359,077