Reckson Operating Partnership 10-K 28 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 27, 2019	Jun. 30, 2018
Document and Entity Information
Entity Registrant Name	RECKSON OPERATING PARTNERSHIP LP
Entity Central Index Key	0000930810
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 0
Entity Common Stock, Shares Outstanding		0
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Commercial real estate properties, at cost:
Land and land interests		$ 1,214,535	$ 1,704,142
Building and improvements		3,171,132	4,251,610
Building leasehold and improvements		1,073,703	1,073,703
Commercial real estate properties, gross		5,459,370	7,029,455
Less: accumulated depreciation		(1,316,217)	(1,492,603)
Total commercial real estate properties, net		4,143,153	5,536,852
Assets held for sale		0	67,228
Cash and cash equivalents		34,480	36,013
Restricted cash		33,075	41,117
Tenant and other receivables, net of allowance of $6,795 and $7,237 in 2018 and 2017, respectively		23,085	31,006
Deferred rents receivable, net of allowance of $9,535 and $11,189 in 2018 and 2017, respectively		180,253	233,300
Debt and preferred equity investments, net of discounts and deferred origination fees of $17,000 and $25,507 in 2018 and 2017, respectively, and allowance of $5,750 in 2018		1,956,119	2,114,041
Investments in unconsolidated joint ventures		339,302	130,217
Deferred costs, net of accumulated amortization of $84,741 and $77,176 in 2018 and 2017, respectively		81,863	106,136
Other assets		217,967	245,598
Total assets(1)	[1]	7,009,297	8,541,508
Liabilities
Mortgages and other loans payable, net		607,569	829,648
Unsecured notes, net		0	901,067
Accrued interest payable		7,680	14,999
Other liabilities		87,077	92,514
Accounts payable and accrued expenses		57,608	60,819
Related party payables		0	23,808
Deferred revenue		18,302	134,650
Deferred land leases payable		1,689	1,888
Dividends payable		807	807
Security deposits		38,296	39,085
Liabilities related to assets held for sale		0	42
Total liabilities	[1]	819,028	2,099,327
Commitments and contingencies
Preferred units		109,161	109,161
Capital
General partner capital		6,056,226	6,012,134
Limited partner capital		0	0
Accumulated other comprehensive loss		0	(1,259)
Total ROP partner's capital		6,056,226	6,010,875
Noncontrolling interests in other partnerships		24,882	322,145
Total capital		6,081,108	6,333,020
Total liabilities and capital		$ 7,009,297	$ 8,541,508
[1]	The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs: $268.6 million and $297.3 million of land, $1.3 billion and $1.4 billion of building and improvements, $319.1 million and $318.4 million of accumulated depreciation, $143.9 million and $160.5 million of other assets included in other line items, $495.0 million and $494.0 million of real estate debt, net, $2.1 million and $2.1 million of accrued interest payable, and $48.8 million and $61.4 million of other liabilities included in other line items as of December 31, 2017 and December 31, 2016, respectively.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Tenant and other receivables, net of allowance of $6,795 and $7,237 in 2018 and 2017, respectively	$ 7,237	$ 4,879
Deferred rents receivable, net of allowance of $9,535 and $11,189 in 2018 and 2017, respectively	11,189	17,798
Debt and preferred equity investments, net of discounts and deferred origination fees of $17,000 and $25,507 in 2018 and 2017, respectively, and allowance of $5,750 in 2018	25,507	16,705
Deferred costs, net of accumulated amortization of $84,741 and $77,176 in 2018 and 2017, respectively	77,176	73,673
Commitments and contingencies
Land	1,214,535	1,704,142
Building and improvements	3,171,132	4,251,610
Accumulated depreciation	1,316,217	1,492,603
Other assets	217,967	245,598
Other liabilities	87,077	92,514
Variable Interest Entity, Primary Beneficiary
Land	268,600	297,300
Building and improvements	1,300,000	1,400,000
Accumulated depreciation	319,100	318,400
Other assets	100	160,500
Real estate debt, net	495,000	494,000
Interest payable	2,100	2,100
Other liabilities	$ 0	$ 61,400

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Rental revenue, net	$ 531,844,000	$ 668,068,000	$ 652,629,000
Escalation and reimbursement	82,583,000	99,887,000	104,683,000
Investment income	190,408,000	193,977,000	214,102,000
Other income	11,268,000	5,606,000	4,002,000
Total revenues	816,103,000	967,538,000	975,416,000
Expenses
Operating expenses, including $24,418 in 2018, $27,929 in 2017, and $25,193 in 2016 of related party expenses	131,212,000	164,219,000	166,137,000
Real estate taxes	130,532,000	156,967,000	152,010,000
Ground rent	19,798,000	20,941,000	20,971,000
Interest expense, net of interest income	62,081,000	123,969,000	109,208,000
Amortization of deferred financing costs	4,532,000	9,313,000	7,918,000
Depreciation and amortization	166,372,000	205,795,000	212,514,000
Loan loss and other investment reserves, net of recoveries	5,750,000	0	0
Transaction related costs	283,000	3,000	238,000
Marketing, general and administrative	627,000	496,000	720,000
Total expenses	521,187,000	681,703,000	669,716,000
Equity in net income from unconsolidated joint ventures	4,198,000	14,192,000	14,509,000
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	5,981,000	672,000	0
Purchase price and other fair value adjustment	54,860,000	0	0
(Loss) gain on sale of real estate	(54,095,000)	69,826,000	(6,909,000)
Depreciable real estate reserves and impairment	(106,376,000)	(172,071,000)	0
Net income	199,484,000	198,454,000	313,300,000
Net (income) loss attributable to noncontrolling interests in other partnerships	(718,000)	17,440,000	(4,424,000)
Preferred units dividend	(3,821,000)	(3,819,000)	(3,821,000)
Net income attributable to ROP common unitholder	$ 194,945,000	$ 212,075,000	$ 305,055,000

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Related party expenses included in operating expenses	$ 27,929	$ 25,193	$ 26,728

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income attributable to ROP common unitholder	$ 194,945	$ 212,075	$ 305,055
Other comprehensive income:
Change in net unrealized gain on derivative instruments	0	359	598
Comprehensive income attributable to ROP common unitholder	$ 194,945	$ 212,434	$ 305,653

Consolidated Statement of Capit

Consolidated Statement of Capital - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Partners' Capital
Beginning Balance	$ 6,333,020	$ 5,528,823	$ 4,586,952
Contributions	2,587,213	4,664,131	4,490,682
Distributions	(2,737,648)	(4,054,928)	(3,858,888)
Net income	195,663	194,635	309,479
Other comprehensive income		359	598
Deconsolidation	(297,140)
Ending Balance	6,081,108	6,333,020	5,528,823
General Partner's Capital Class A Common Units | Class A Common Units
Increase (Decrease) in Partners' Capital
Beginning Balance	6,012,134	5,139,842	4,201,872
Contributions	2,585,954	4,664,031	4,490,682
Distributions	(2,736,807)	(4,003,814)	(3,857,767)
Net income	194,945	212,075	305,055
Ending Balance	6,056,226	6,012,134	5,139,842
Limited Partner's Capital
Increase (Decrease) in Partners' Capital
Beginning Balance	0	0	0
Ending Balance	0	0	0
Noncontrolling Interests In Other Partnerships
Increase (Decrease) in Partners' Capital
Beginning Balance	322,145	390,599	387,296
Contributions		100	0
Distributions	(841)	(51,114)	(1,121)
Net income	718	(17,440)	4,424
Deconsolidation	(297,140)
Ending Balance	24,882	322,145	390,599
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Partners' Capital
Beginning Balance	(1,259)	(1,618)	(2,216)
Contributions	1,259
Other comprehensive income		359	598
Ending Balance	$ 0	$ (1,259)	$ (1,618)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 199,484,000	$ 198,454,000	$ 313,300,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	170,904,000	215,108,000	220,432,000
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	(5,981,000)	(672,000)	0
Equity in net income from unconsolidated joint ventures	(4,198,000)	(14,192,000)	(14,509,000)
Distributions of cumulative earnings from unconsolidated joint ventures	3,850,000	14,613,000	10,430,000
Loan loss and other investment reserves, net of recoveries	5,750,000	0	0
Purchase price and other fair value adjustment	(54,860,000)	0	0
Depreciable real estate reserves and impairment	106,376,000	172,071,000	0
(Gain) loss on sale of real estate, net	54,095,000	(69,826,000)	6,909,000
Deferred rents receivable	6,037,000	(6,762,000)	(23,768,000)
Other non-cash adjustments	(40,387,000)	(46,015,000)	(53,206,000)
Changes in operating assets and liabilities:
Tenant and other receivables	(1,813,000)	(3,139,000)	1,511,000
Deferred lease costs	(21,077,000)	(13,005,000)	(27,625,000)
Other assets	(3,324,000)	(11,431,000)	12,872,000
Accounts payable, accrued expenses, other liabilities, and security deposits	174,000	(5,722,000)	(2,937,000)
Deferred revenue and land leases payable	84,000	(1,385,000)	1,684,000
Net cash provided by operating activities	415,114,000	428,097,000	445,093,000
Investing Activities
Acquisitions of real estate property	0	(228,000)	0
Additions to land, buildings and improvements	(137,414,000)	(120,766,000)	(127,200,000)
Investments in unconsolidated joint venture	(20,449,000)	(488,000)	(25,373,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	116,381,000	49,270,000	1,304,000
Net proceeds from disposition of real estate/joint venture interest	328,256,000	344,443,000	42,316,000
Other investments	(40,776,000)	57,655,000	14,292,000
Origination of debt and preferred equity investments	(814,334,000)	(1,129,493,000)	(977,699,000)
Repayments or redemption of preferred equity investments	689,346,000	782,914,000	904,517,000
Net cash provided by (used in) investing activities	121,010,000	(16,693,000)	(167,843,000)
Financing Activities
Proceeds from mortgages and other loans payable	306,638,000	340,809,000	50,383,000
Repayments of mortgages and other loans payable	0	(184,642,000)	(119,165,000)
Proceeds from revolving credit facility, term loan and senior unsecured notes	0	1,898,134,000	1,325,300,000
Repayments of revolving credit facility term loan and senior unsecured notes	(250,000,000)	(1,792,971,000)	(2,324,608,000)
Contributions from common unitholder	1,777,090,000	3,348,730,000	4,490,682,000
Contributions from noncontrolling interests in other partnerships	0	100,000	0
Distributions to noncontrolling interests in other partnerships	(841,000)	(51,114,000)	(1,121,000)
Distributions to common and preferred unitholder	(2,374,759,000)	(4,007,580,000)	(3,738,853,000)
Deferred loan costs and capitalized lease obligation	(3,936,000)	(5,520,000)	(5,058,000)
Other obligation related to mortgage loan participation	109,000	16,361,000	59,150,000
Net cash used in provided by financing activities	(545,699,000)	(437,693,000)	(263,290,000)
Net (decrease) increase in cash, restricted cash, and cash equivalents	(9,575,000)	(26,289,000)	13,960,000
Cash, restricted cash, and cash equivalents at beginning of year	77,130,000	103,419,000	89,459,000
Cash, restricted cash, and cash equivalents at end of year	67,555,000	77,130,000	103,419,000
Supplemental Cash Flow Disclosure:
Interest paid	58,350,000	125,289,000	110,656,000
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Tenant improvements and capital expenditures payable	0	2,018,000	4,029,000
Transfer of assets to assets held for sale	0	340,683,000	0
Transfer of liabilities related to assets held for sale	0	1,332,000	0
Contributions from common unitholder	808,864,000	1,315,301,000	0
Distributions to common unitholder	365,869,000	0	0
Distribution of land to common unitholder	0	0	8,980,000
Deconsolidation of a subsidiary	280,718,000	3,520,000	0
Exchange of debt investment for equity in joint venture	0	0	68,581,000
Removal of fully depreciated commercial real estate properties	15,571,000	0	12,326,000
Settlement of related party receivable with SL Green common stock	0	0	90,000,000
Issuance of related party payable for SL Green common stock	0	0	23,808,000
Cash and cash equivalents	34,480,000	36,013,000	59,930,000
Total cash, cash equivalents, and restricted cash	$ 77,130,000	$ 103,419,000	$ 89,459,000

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
	Dec. 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 95.30% owned by SL Green Realty Corp., or SL Green, as of December 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. SL Green and the Operating Partnership were formed in June 1997. SL Green has qualified, and expects to qualify in the current fiscal year, as a real estate investment trust, or REIT, under the Internal Revenue Code of 1986, as amended, or the Code, and operates as a self-administered, self-managed REIT. A REIT is a legal entity that holds real estate interests and, through payments of dividends to stockholders, is permitted to minimize the payment of Federal income taxes at the corporate level. On January 25, 2007, SL Green completed the acquisition of all of the outstanding shares of common stock of Reckson Associates Realty Corp., or RARC, our prior general partner. This transaction is referred to herein as the Merger. As of December 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 Properties Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office (2) 15 8,303,245 94.9 % Retail (3)(4) 5 364,816 99.4 % Development/Redevelopment 1 160,000 96.0 % 21 8,828,061 95.1 % Suburban Office 6 1,432,400 94.3 % Retail 1 52,000 100.0 % 7 1,484,400 94.5 % Total commercial properties 28 10,312,461 95.0 % Residential: Manhattan Residential (3) — 222,855 96.1 % Total portfolio 28 10,535,316 95.0 % ____________________________________________________________________ (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 December 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 (unaudited). As of December 31, 2018 , we also held debt and preferred equity investments with a book value of $2.0 billion .

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 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. A noncontrolling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to us. Noncontrolling interests are required to be presented as a separate component of equity in the consolidated balance sheet and the presentation of net income is modified to present earnings and other comprehensive income attributed to controlling and noncontrolling interests. We assess the accounting treatment for each joint venture and debt and preferred equity investment. This assessment includes a review of each joint venture or limited liability company agreement to determine the rights provided to each party and whether those rights are protective or participating. For all VIEs, we review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity's economic performance. In situations where we and our partner approve, among other things, the annual budget, receive a detailed monthly reporting package, meet on a quarterly basis to review the results of the joint venture, review and approve the joint venture's tax return before filing, and approve all leases that cover more than a nominal amount of space relative to the total rentable space at each property, we do not consolidate the joint venture as we consider these to be substantive participation rights that result in shared power of the activities that most significantly impact the performance of the joint venture. Our joint venture agreements typically contain certain protective rights such as requiring partner approval to sell, finance or refinance the property and the payment of capital expenditures and operating expenditures outside of the approved budget or operating plan. Investment in Commercial Real Estate Properties Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their respective fair values on the acquisition date. When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of operations. See Note 3, "Property Acquisitions." We allocate the purchase price of real estate to land and building (inclusive of tenant improvements) and, if determined to be material, intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases. We depreciate the amount allocated to building (inclusive of tenant improvements) over their estimated useful lives, which generally range from three to 40 years . We amortize the amount allocated to the above- and below-market leases over the remaining term of the associated lease, which generally range from one to 14 years , and record it as either an increase (in the case of below-market leases) or a decrease (in the case of above-market leases) to rental income. We amortize the amount allocated to the values associated with in-place leases over the expected term of the associated lease, which generally ranges from one to 14 years . If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The tenant improvements and origination costs are amortized as an expense over the remaining life of the lease (or charged against earnings if the lease is terminated prior to its contractual expiration date). We assess fair value of the leases based on estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. To the extent acquired leases contain fixed rate renewal options that are below-market and determined to be material, we amortize such below-market lease value into rental income over the renewal period. As of December 31, 2018 , the weighted average amortization period for above-market leases, below-market leases, and in-place lease costs is 4.2 years, 7.7 years, and 4.6 years, respectively. We incur a variety of costs in the development and leasing of our properties. After the determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year after major construction activity ceases. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction. Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows: Category Term Building (fee ownership) 40 years Building improvements shorter of remaining life of the building or useful life Building (leasehold interest) lesser of 40 years or remaining term of the lease Property under capital lease remaining lease term Furniture and fixtures four to seven years Tenant improvements shorter of remaining term of the lease or useful life Depreciation expense (including amortization of capital lease assets) totaled $150.8 million , $188.9 million , and $196.2 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be 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 and depreciation expense is no longer recorded. See Note 4, "Properties Held for Sale and Dispositions." We recognized $6.7 million , $17.0 million , and $20.2 million of rental revenue for the years ended December 31, 2018 , 2017 , and 2016 , respectively, for the amortization of aggregate below-market leases in excess of above-market leases and a reduction in lease origination costs, resulting from the allocation of the purchase price of the applicable properties. The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Identified intangible assets (included in other assets): Gross amount $ 213,421 $ 276,163 Accumulated amortization (201,010 ) (236,737 ) Net (1) $ 12,411 $ 39,426 Identified intangible liabilities (included in deferred revenue): Gross amount $ 230,275 $ 496,438 Accumulated amortization (216,362 ) (366,091 ) Net (1) $ 13,913 $ 130,347 (1) As of December 31, 2018, no net intangible assets and no net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale. As of December 31, 2017, $0.1 million net intangible assets and $0.1 million net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale. The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands): 2019 $ (5,166 ) 2020 (4,398 ) 2021 (1,495 ) 2022 (1,192 ) 2023 (633 ) The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands): 2019 $ 5,486 2020 4,728 2021 3,376 2022 1,813 2023 1,453 Cash and Cash Equivalents We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents. Restricted Cash Restricted cash primarily consists of security deposits held on behalf of our tenants, interest reserves, as well as capital improvement and real estate tax escrows required under certain loan agreements. Fair Value Measurements See Note 11, "Fair Value Measurements." Investments in Unconsolidated Joint Ventures We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity in net income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture and includes adjustments related to basis differences that were identified as part of the initial accounting for the investment. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us. See Note 6, "Investments in Unconsolidated Joint Ventures." We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at December 31, 2018 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some of the residual profit from such projects. When the risk and rewards of these arrangements are essentially the same as an investor or joint venture partner, we account for these arrangements as real estate investments under the equity method of accounting for investments. Otherwise, we account for these arrangements consistent with the accounting for our debt and preferred equity investments. Deferred Lease Costs Deferred lease costs consist of fees and direct costs incurred to execute operating leases and are amortized on a straight-line basis over the related lease term. Deferred Financing Costs Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close. Deferred financing costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. Revenue Recognition Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year. We record a gain on sale of real estate assets when we no longer hold a controlling financial interest in the entity holding the real estate, a contract exists with a third party and that third party has control of the assets acquired. Investment income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt. Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as an adjustment to interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cash flows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield. Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received. We may syndicate a portion of the loans that we originate or sell the loans individually. When a transaction meets the criteria for sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, original issue discounts, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of operations. Any fees received at the time of sale or syndication are recognized as part of investment income. Asset management fees are recognized on a straight-line basis over the term of the asset management agreement. Allowance for Doubtful Accounts We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required. Allowance for Loan Loss and Other Investment Reserves The expense for loan loss and other investment reserves in connection with debt and preferred equity investments is the charge to earnings to adjust the allowance for possible losses to the level that we estimate to be adequate, based on Level 3 data, considering delinquencies, loss experience and collateral quality. The Company evaluates debt and preferred equity investments that are classified as held to maturity for possible impairment or credit deterioration associated with the performance and/or value of the underlying collateral property as well as the financial and operating capability of the borrower/sponsor. Quarterly, the Company assigns each loan a risk rating. Based on a 3-point scale, loans are rated “1” through “3,” from less risk to greater risk, which ratings are defined as follows: 1 - Low Risk Assets - Low probability of loss, 2 - Watch List Assets - Higher potential for loss, 3 - High Risk Assets - Loss more likely than not. When it is probable that we will be unable to collect all amounts contractually due, the investment is considered impaired. 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. Debt and preferred equity investments that are classified as held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment. Rent Expense Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred lease payable on the consolidated balance sheets. Exchangeable Debt Instruments The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, are bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate the liability component of exchangeable debt based on the present value of the contractual cash flows discounted at our comparable market conventional debt borrowing rate at the date of issuance. The difference between the principal amount and the fair value of the liability component is reported as a discount on the exchangeable debt that is accreted as additional interest expense from the issuance date through the contractual maturity date using the effective interest method. A portion of this additional interest expense may be capitalized to the development and redevelopment balances qualifying for interest capitalization each period. The liability component of the exchangeable debt is reported net of discounts on our consolidated balance sheets. We calculate the equity component of exchangeable debt based on the difference between the initial proceeds received from the issuance of the exchangeable debt and the fair value of the liability component at the issuance date. The equity component is included in additional paid-in-capital, net of issuance costs, on our consolidated balance sheets. We allocate issuance costs for exchangeable debt between the liability and the equity components based on their relative values. Income Taxes SL Green is taxed as a REIT under Section 856(c) of the Code. As a REIT, SL Green generally is not subject to Federal income tax. To maintain its qualification as a REIT, SL Green must distribute at least 90% of its REIT taxable income to its stockholders and meet certain other requirements. If SL Green fails to qualify as a REIT in any taxable year, SL Green will be subject to Federal income tax on its taxable income at regular corporate rates. SL Green may also be subject to certain state, local and franchise taxes. Under certain circumstances, Federal income and excise taxes may be due on its undistributed taxable income. 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. We follow a two-step approach for evaluating uncertain tax positions. Recognition (step one) occurs when an enterprise concludes that a tax position, based solely on its technical merits, is more-likely-than-not to be sustained upon examination. Measurement (step two) determines the amount of benefit that is more-likely-than-not to be realized upon settlement. Derecognition of a tax position that was previously recognized would occur when a company subsequently determines that a tax position no longer meets the more-likely-than-not threshold of being sustained. The use of a valuation allowance as a substitute for derecognition of tax positions is prohibited. On December 22, 2017, the Tax Cuts and Jobs Act (the ‘‘Tax Act’’) was signed into law and makes substantial changes to the Code. The Tax Act has not had a material impact on our financial statements for the years ended December 31, 2018 or December 31, 2017 . Derivative Instruments In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collars and floors, to manage, or hedge, interest rate risk. Effectiveness is essential for those derivatives that we intend to qualify for hedge accounting. Some derivative instruments are associated with an anticipated transaction. In those cases, hedge effectiveness criteria also require that it be probable that the underlying transaction occurs. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract. To determine the fair values of derivative instruments, we use a variety of methods and assumptions that are based on market conditions and risks existing at each balance sheet date. For the majority of financial instruments including most derivatives, long-term investments and long-term debt, standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost, and termination cost are used to determine fair value. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized. In the normal course of business, we are exposed to the effect of interest rate changes and limit these risks by following established risk management policies and procedures including the use of derivatives. To address exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices and manage the cost of borrowing obligations. We use a variety of conventional derivative products. These derivatives typically include interest rate swaps, caps, collars and floors. We expressly prohibit the use of unconventional derivative instruments and using derivative instruments for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. We may employ swaps, forwards or purchased options to hedge qualifying forecasted transactions. Gains and losses related to these transactions are deferred and recognized in net income as interest expense in the same period or periods that the underlying transaction occurs, expires or is otherwise terminated. Hedges that are reported at fair value and presented on the balance sheet could be characterized as cash flow hedges or fair value hedges. Interest rate caps and collars are examples of cash flow hedges. Cash flow hedges address the risk associated with future cash flows of interest payments. For all hedges held by us and which were deemed to be fully effective in meeting the hedging objectives established by our corporate policy governing interest rate risk management, no net gains or losses were reported in earnings. The changes in fair value of hedge instruments are reflected in accumulated other comprehensive income. For derivative instruments not designated as hedging instruments, the gain or loss, resulting from the change in the estimated fair value of the derivative instruments, is recognized in current earnings during the period of change. Shares Contributed by Parent Company We record contributed shares of SL Green common stock as a reduction to general partner's capital in our financial statements. Earnings per Unit Earnings per unit was not computed in 2018 , 2017 and 2016 as there were no outstanding common units held by third parties at December 31, 2018 , 2017 and 2016 . 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 prim

Property Acquisitions

Property Acquisitions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions During the years ended December 31, 2018 , 2017 , and 2016 we did not acquire any properties from a third party.

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	12 Months Ended
	Dec. 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 As of December 31, 2018 , no properties were classified as held for sale. Property Dispositions The following table summarizes the properties sold during the years ended December 31, 2018 , 2017 and 2016 : Property Disposition Date Property Type (unaudited) Approximate Usable Square Feet Sales Price (1) (in millions) Gain (Loss) on Sale (2) (in millions) 400 Summit Lake Drive November 2018 Land 39.5 acres $ 3.0 $ (36.2 ) 1-6 International Drive July 2018 Office 540,000 55.0 (2.6 ) 635 Madison Avenue June 2018 Retail 176,530 153.0 (14.1 ) 115-117 Stevens Avenue May 2018 Office 178,000 12.0 (0.7 ) 125 Chubb Way October 2017 Office 278,000 29.5 (26.1 ) 16 Court Street October 2017 Office 317,600 171.0 64.9 680-750 Washington Boulevard July 2017 Office 325,000 97.0 (44.2 ) 520 White Plains Road April 2017 Office 180,000 21.0 (14.6 ) 102 Greene Street (3) April 2017 Retail 9,200 43.5 4.9 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) (1) Sales price represents the actual sales price for an entire property or the gross asset valuation for interests in a property. (2) The gain on sale for 16 Court Street and 102 Greene Street are net of $2.5 million and $0.9 million , respectively, in employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In April 2017, we closed on the sale of a 90 % interest 102 Greene Street and had subsequently accounted for our interest in the property as an investment in unconsolidated joint ventures. We sold the remaining 10 % interest in September 2017. See Note 6, "Investments in Unconsolidated Joint Ventures."

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments Below is a summary of the activity relating to our debt and preferred equity investments as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Balance at beginning of period (1) $ 2,114,041 $ 1,640,412 Debt investment originations/accretion (2) 834,304 1,142,591 Preferred equity investment originations/accretion (2) 8,430 144,456 Redemptions/sales/syndications/amortization (3) (994,906 ) (813,418 ) Net change in loan loss reserves (5,750 ) — Balance at end of period (1) $ 1,956,119 $ 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 and are included in other assets and other liabilities on the consolidated balance sheets. The following table is a rollforward of our total loan loss reserves at December 31, 2018 , 2017 and 2016 (in thousands): December 31, 2018 2017 2016 Balance at beginning of year $ — $ — $ — Expensed 5,750 — — Recoveries — — — Charge-offs and reclassifications — — — Balance at end of period $ 5,750 $ — $ — At December 31, 2018 , all debt and preferred equity investments were performing in accordance with the terms of the relevant investments. At December 31, 2018 the Company's loan loss reserves of $5.8 million were attributable to two investments with an unpaid principal balance of $159.9 million that are being marketed for sale, are performing in accordance with their respective terms, and were not put on nonaccrual. At December 31, 2017 , all debt and preferred equity investments were performing in accordance with the terms of the relevant investments, with the exception of our investment in 2 Herald Square which was purchased in maturity default in May 2017 and April 2017, respectively, for which we subsequently were the successful bidder for the leasehold interest at the foreclosure of the asset as discussed in Note 3, "Property Acquisitions," and a junior mortgage participation acquired in September 2014, which was acquired for zero , had a carrying value of zero and was canceled in 2018. We have determined that we have one portfolio segment of financing receivables at December 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 $136.5 million and $93.4 million at December 31, 2018 and 2017 , respectively. No financing receivables were 90 days past due at December 31, 2018 with the exception of a $28.4 million financing receivable which was put on nonaccrual in August as a result of interest default. The loan was evaluated in accordance with our loan review procedures and the Company concluded that the fair value of the collateral exceeded the carrying amount of the loan. As of December 31, 2018, Management estimated the weighted average risk rating for our debt and preferred equity investments to be 1.2 . Debt Investments As of December 31, 2018 and 2017 , we held the following debt investments with an aggregate weighted average current yield of 8.99% , at December 31, 2018 (in thousands): Loan Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior Financing December 31, 2018 Carrying Value (1) December 31, 2017 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Mezzanine Loan (3a) $ — $ 1,160,000 $ 213,185 $ 204,005 March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,932 24,913 April 2022 Mezzanine Loan — 280,000 36,585 34,600 August 2022 Mezzanine Loan — 85,097 12,706 12,699 November 2023 Mezzanine Loan — 180,000 30,000 — December 2023 Mezzanine Loan (3b) — 115,000 12,941 12,932 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 11,000 15,000 November 2026 Mezzanine Loan — 1,712,750 55,250 55,250 June 2027 Mortgage/Jr. Mortgage Loan (4) — — — 250,464 Mortgage Loan (5) — — — 26,366 Mortgage Loan (5) — — — 239 Loan Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior Financing December 31, 2018 Carrying Value (1) December 31, 2017 Carrying Value (1) Maturity Date (2) Total fixed rate $ — $ 4,129,847 $ 430,099 $ 669,968 Floating Rate Investments: Mezzanine Loan (6) $ — $ 45,025 $ 37,499 $ 34,879 January 2019 Mezzanine Loan (3c)(7) — 85,000 15,333 15,381 March 2019 Mezzanine Loan (3d)(7) — 65,000 14,822 14,869 March 2019 Mezzanine Loan (9) — 38,000 21,990 21,939 March 2019 Mezzanine Loan (8) — 40,000 19,986 19,982 April 2019 Mezzanine Loan — 265,000 24,961 24,830 April 2019 Mortgage/Jr. Mortgage Participation Loan 40,530 233,086 84,012 71,832 August 2019 Mezzanine Loan (8)(9) — 65,000 14,998 14,955 August 2019 Mortgage/Mezzanine Loan (8) — — 19,999 19,940 August 2019 Mortgage/Mezzanine Loan 1,027 — 154,070 143,919 September 2019 Mezzanine Loan — 350,000 34,886 34,737 October 2019 Mortgage/Mezzanine Loan (10) 7,243 — 62,493 43,845 January 2020 Mezzanine Loan (10) 559 575,955 79,164 75,834 January 2020 Mortgage Loan 11,204 — 88,501 — February 2020 Mezzanine Loan 1,277 322,300 53,402 — March 2020 Mortgage/Mezzanine Loan 14,860 — 277,694 — April 2020 Mortgage/Mezzanine Loan (8) — — 37,094 — June 2020 Mezzanine Loan 7,887 38,167 12,627 11,259 July 2020 Mortgage/Mezzanine Loan — — 83,449 — October 2020 Mezzanine Loan 38,575 362,908 88,817 75,428 November 2020 Mortgage/Mezzanine Loan 33,131 — 98,804 88,989 December 2020 Mortgage/Mezzanine Loan — — 35,266 35,152 December 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,665 15,635 July 2021 Mezzanine Loan (9) — 38,596 7,305 34,947 December 2021 Mortgage/Mezzanine Loan (5) — — — 162,553 Mortgage/Mezzanine Loan (5) — — — 74,755 Mortgage/Mezzanine Loan (11) — — — 23,609 Mortgage/Mezzanine Loan (5) — — — 16,969 Mezzanine Loan (5) — — — 59,723 Mezzanine Loan (5) — — — 37,851 Mezzanine Loan (5) — — — 14,855 Mezzanine Loan (9) — — — 12,174 Mezzanine Loan (9) — — — 10,934 Mezzanine Loan (5) — — — 37,250 Mezzanine Loan (5) — — — 15,148 Mezzanine Loan (5) — — — 8,550 Mezzanine Loan (9) — — — 26,927 Total floating rate $ 156,293 $ 2,584,037 $ 1,382,837 $ 1,299,650 Total $ 156,293 $ 6,713,884 $ 1,812,936 $ 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) 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 , and (d) $14.1 million . (4) These loans were conveyed to SL Green in the form of a distribution in 2018. (5) This loan was repaid in 2018. (6) As of January 2019, this loan is in maturity default. No impairment was recorded as the Company believes that the fair value of the property exceeded the carrying amount of the loans. (7) This loan was extended in 2019. (8) This loan was extended in 2018. (9) This loan was repaid in 2019. (10) This loan was modified in 2019. (11) This loan was sold in 2018. Preferred Equity Investments As of December 31, 2018 and 2017 , we held the following preferred equity investments with an aggregate weighted average current yield of 5.80% at December 31, 2018 (in thousands): Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior December 31, 2018 (1) December 31, 2017 (1) Mandatory Redemption (2) Preferred Equity $ — $ 272,000 $ 143,183 $ 144,423 April 2021 $ — $ 272,000 $ 143,183 $ 144,423 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options.

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	12 Months Ended
	Dec. 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 December 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 December 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 (4) Invesco Real Estate 20.00% 20.00% 68,342 August 2015 $ 277,750 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of December 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 January 2019, we closed on the sale of our interest in this property to our joint venture partner. The transaction generated net cash proceeds to the Company of $15.2 million . Acquisition, Development and Construction Arrangements Based on the characteristics of the following arrangements, which are similar to those of an investment, combined with the expected residual profit of not greater than 50% , we have accounted for these debt and preferred equity investments under the equity method. As of December 31, 2018 and 2017 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type December 31, 2018 December 31, 2017 Maturity Date Mezzanine Loan and Preferred Equity (1) $ — $ 100,000 Mezzanine Loan (2) — 26,716 $ — $ 126,716 (1) The mezzanine loan was repaid and the preferred equity interest was redeemed in March 2018. (2) The Company was redeemed on this investment in July 2018. Disposition of Joint Venture Interests or Properties The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2018 , 2017 , and 2016 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) (Loss) Gain on Sale (in thousands) (2) 2 Herald Square (3) 49.00% November 2018 Ownership Interest $ 265,000 $ — Mezzanine Loan (4) 33.33% August 2018 Repayment 15,000 N/A 102 Greene Street 10.00% September 2017 Ownership Interest 43,500 283 76 11th Avenue (5) 33.33% May 2017 Repayment 138,240 N/A (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. (3) In May 2018, SL Green assigned the Company a 49.0% tenancy-in-common interest in the leasehold interest in 2 Herald Square and in November 2018, we closed on the sale of this investment. (4) In August 2018, our investment in a joint venture that owned a mezzanine loan secured by a commercial property in midtown Manhattan was repaid after the joint venture received repayment of the underlying loan. (5) In May 2017, our investment in a joint venture that owned two mezzanine notes secured by interests in the entity that owns 76 11th Avenue was repaid after the joint venture received repayment of the underlying loans. Joint Venture Mortgages and Other Loans Payable We generally finance our joint ventures with non-recourse debt. In certain cases we may provide guarantees or master leases for tenant space, which terminate upon the satisfaction of specified circumstances or repayment of the underlying loans. The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2018 and 2017 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) December 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 (3) 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 (1,754 ) (2,862 ) Total joint venture mortgages and other loans payable, net $ 639,246 $ 138,138 (1) Economic interest represents the Company's interests in the joint venture as of December 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 December 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified. (3) In January 2019, we closed on the sale of our interest in this property to our joint venture partner. The combined balance sheets for the unconsolidated joint ventures, at December 31, 2018 and 2017 are as follows (in thousands): December 31, 2018 December 31, 2017 Assets Commercial real estate property, net $ 1,802,698 $ 273,116 Debt and preferred equity investments, net — 141,716 Other assets 479,005 15,735 Total assets $ 2,281,703 $ 430,567 Liabilities and members' equity Mortgages and other loans payable, net $ 639,246 $ 138,138 Other liabilities 608,469 18,908 Members' equity 1,033,988 273,521 Total liabilities and members' equity $ 2,281,703 $ 430,567 Company's investments in unconsolidated joint ventures $ 339,302 $ 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 years ended December 31, 2018 , 2017 , and 2016 are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Total revenues $ 147,411 $ 35,204 $ 38,524 Operating expenses 24,977 877 1,238 Real estate taxes 30,462 1,389 1,192 Ground rent 1,851 — — Interest expense, net of interest income 32,849 3,769 2,895 Amortization of deferred financing costs 1,108 1,114 1,108 Depreciation and amortization 50,468 8,405 8,404 Total expenses $ 141,715 $ 15,554 $ 14,837 Net income $ 5,696 $ 19,650 $ 23,687 Company's equity in net income from unconsolidated joint ventures $ 4,198 $ 14,192 $ 14,509 (1) The combined statements of operations 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	12 Months Ended
	Dec. 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 December 31, 2018 and 2017 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 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 2019 L+ 2.34% $ 300,000 $ 90,809 115 Spring Street September 2023 L+ 3.40% 65,550 — Total mortgages and other loans payable $ 615,550 $ 840,809 Deferred financing costs, net of amortization (7,981 ) (11,161 ) Total mortgages and other loans payable, net $ 607,569 $ 829,648 (1) Interest rate as of December 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 December 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 $1.0 billion and $1.9 billion , respectively. At December 31, 2018 , the Company held $20.0 million of debt and preferred equity investments collateralizing mortgages and other loans payable by SL Green. 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. In June 2018, we exercised a one -year extension option. At December 31, 2018 , the facility had a carrying value of $299.6 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 . In June 2018, we terminated the restated 2016 MRA. The facility bore interest ranging from 225 and 400 basis points over 30-day LIBOR depending on the pledged collateral and had an initial two -year term, with a one year extension option. Since December 6, 2015, we had 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 was less than $150.0 million .

Corporate Indebtedness

Corporate Indebtedness	12 Months Ended
	Dec. 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 provided 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. In December 2018, the Company was removed as a guarantor on the facility. Senior Unsecured Notes The following table sets forth our senior unsecured notes and other related disclosures as of December 31, 2018 and 2017 , respectively, by scheduled maturity date (dollars in thousands): Issuance December 31, 2018 Unpaid Principal Balance December 31, 2018 Accreted Balance December 31, 2017 Accreted Balance Coupon Initial Term Maturity Date March 16, 2010 (1) (4) $ — $ — $ 250,000 November 15, 2012 (2) (4) — — 305,163 December 17, 2015 (1) (4) — — 100,000 August 5, 2011 (1) (3) — — 249,953 $ — $ — $ 905,116 Deferred financing costs, net — — (4,049 ) $ — $ — $ 901,067 (1) Issued by SL Green, the Operating Partnership and ROP, as co-obligors. (2) 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% . (3) Balance was repaid in August 2018. (4) In December 2018, ROP was released as a co-obligor from the senior unsecured notes. This resulted in these notes being removed from our consolidated balance sheet and shown as a non-cash capital contribution. Principal Maturities Combined aggregate principal maturities of mortgages and other loans payable as of December 31, 2018 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Total Joint Venture Debt 2019 $ — $ — $ — $ — 2020 — 300,000 300,000 28,200 2021 — — — — 2022 — — — — 2023 — 65,550 65,550 255,000 Thereafter — 250,000 250,000 — $ — $ 615,550 $ 615,550 $ 283,200 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Year Ended December 31, 2018 2017 2016 Interest expense before capitalized interest $ 67,647 $ 124,507 $ 110,393 Interest capitalized (5,560 ) (533 ) (1,171 ) Interest income (6 ) (5 ) (14 ) Interest expense, net $ 62,081 $ 123,969 $ 109,208

Preferred Units

Preferred Units	12 Months Ended
	Dec. 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 December 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 December 31, 2018 , the carrying amount of the derivative remained at zero .

Partners' Capital

Partners' Capital	12 Months Ended
	Dec. 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	12 Months Ended
	Dec. 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. The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2018 and 2017 (in thousands): December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Interest rate cap and swap agreements (included in other assets) $ — $ — $ — $ — December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Interest rate cap and swap agreements (included in other assets) $ 167 $ — $ 167 $ — We determine 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 December 2018, the Company determined that it was more likely than not that its suburban properties would be sold or otherwise disposed of significantly before the end of their previously estimated useful life. The Company tested the recoverability of the assets and, as a result of the carrying amount of the assets not being deemed recoverable and exceeding their fair value as measured on a asset by asset basis, recorded a $106.4 million impairment loss. These charges are included in depreciable real estate reserves and impairment in the consolidated statement of operations. The fair value of the assets were determined 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 December 31, 2018 and December 31, 2017 (in thousands): December 31, 2018 December 31, 2017 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,956,119 (2) $ 2,114,041 (2) Fixed rate debt $ 250,000 $ 249,919 $ 1,655,116 $ 1,715,501 Variable rate debt 365,550 374,387 90,809 92,087 $ 615,550 $ 624,306 $ 1,745,925 $ 1,807,588 (1) Amounts exclude net deferred financing costs. (2) At December 31, 2018 , debt and preferred equity investments had an estimated fair value ranging between $2.0 billion and $2.2 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 December 31, 2018 and 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	12 Months Ended
	Dec. 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. As of December 31, 2018 , the Company had not designated any interest rate swap agreements on any debt investment. During the years ended December 31, 2018 , 2017 , and 2016 , we recorded (losses) gains on the changes in the fair value of $(0.2) million , $0.2 million , and $0.0 million , respectively, which are included in investment income in the consolidated statements of operations. 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 December 31, 2018 and 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 years ended December 31, 2018 , 2017 , and 2016 , respectively (in thousands): Amount of Loss Recognized in Other Comprehensive Loss (Effective Portion) Location of Loss Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location of Gain Recognized in Income on Derivative Amount of Gain Recognized into Income (Ineffective Portion) Year Ended December 31, Year Ended December 31, Year Ended December 31, Derivative 2018 2017 2016 2018 2017 2016 2018 2017 2016 Interest Rate Swap $ — $ — $ (13 ) Interest expense $ — $ 359 $ 611 Interest expense $ — $ — $ 3

Rental Income

Rental Income	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Rental Income	Rental Income We are the lessor and the sublessor to tenants under operating leases with expiration dates ranging from January 1, 2019 to 2050. The minimum rental amounts due under the leases are generally either subject to scheduled fixed increases or adjustments. The leases generally also require that the tenants reimburse us for increases in certain operating costs and real estate taxes above their base year costs. Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2018 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands): Consolidated Properties Unconsolidated Properties 2019 $ 514,204 $ 45,500 2020 463,658 44,765 2021 412,040 47,595 2022 373,056 32,693 2023 328,287 32,759 Thereafter 1,362,314 250,340 $ 3,453,559 $ 453,652

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 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, who serves as a member and as the chairman emeritus of SL Green's board of directors, and provide services to certain properties owned by us. Alliance’s affiliates include First Quality Maintenance, L.P., or First Quality, Classic Security LLC, Bright Star Couriers LLC and Onyx Restoration Works, and provide cleaning, extermination, security, messenger, and restoration services, respectively. In addition, First Quality has the non-exclusive opportunity to provide cleaning and related services to individual tenants at our properties on a basis separately negotiated with any tenant seeking such additional services. The Service Corporation has entered into an arrangement with Alliance whereby it will receive a profit participation above a certain threshold for services provided by Alliance to certain tenants at certain buildings above the base services specified in their lease agreements. Income earned from profit participation, which is included in other income on the consolidated statements of operations, was $3.4 million , $3.4 million and $3.3 million for the years ended December 31, 2018 , 2017 and 2016 respectively. We also recorded expenses, inclusive of capitalized expenses, of $9.3 million , $10.0 million and $8.1 million for the years ended December 31, 2018 , 2017 and 2016 respectively, for these services (excluding services provided directly to tenants). 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 $11.2 million , $12.8 million and $11.5 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Insurance We obtained insurance coverage through an insurance program administered by SL Green. In connection with this program, we incurred insurance expense of approximately $4.2 million , $5.4 million , and $5.9 million for the years ended December 31, 2018 , 2017 and 2016 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 bore interest at an annual rate of 6.0% , compounded quarterly. This note matured on August 22, 2018 and is shown as a non-cash contribution.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans The building employees are covered by multi-employer defined benefit pension plans and post-retirement health and welfare plans. We participate in the Building Service 32BJ, or Union, Pension Plan and Health Plan. The Pension Plan is a multi-employer, non-contributory defined benefit pension plan that was established under the terms of collective bargaining agreements between the Service Employees International Union, Local 32BJ, the Realty Advisory Board on Labor Relations, Inc. and certain other employees. This Pension Plan is administered by a joint board of trustees consisting of union trustees and employer trustees and operates under employer identification number 13-1879376. The Pension Plan year runs from July 1 to June 30. Employers contribute to the Pension Plan at a fixed rate on behalf of each covered employee. Separate actuarial information regarding such pension plans is not made available to the contributing employers by the union administrators or trustees, since the plans do not maintain separate records for each reporting unit. However, on September 28, 2016, September 28, 2017, and September 28, 2018, the actuary certified that for the plan years beginning July 1, 2016, July 1, 2017, and July 1, 2018, the Pension Plan was in critical status under the Pension Protection Act of 2006. The Pension Plan trustees adopted a rehabilitation plan consistent with this requirement. No surcharges have been paid to the Pension Plan as of December 31, 2018 . For the Pension Plan years ended June 30, 2018 , 2017 , and 2016 , the plan received contributions from employers totaling $272.3 million , $257.8 million , and $249.5 million , respectively. Our contributions to the Pension Plan represent less than 5.0% of total contributions to the plan. The Health Plan was established under the terms of collective bargaining agreements between the Union, the Realty Advisory Board on Labor Relations, Inc. and certain other employers. The Health Plan provides health and other benefits to eligible participants employed in the building service industry who are covered under collective bargaining agreements, or other written agreements, with the Union. The Health Plan is administered by a Board of Trustees with equal representation by the employers and the Union and operates under employer identification number 13-2928869. The Health Plan receives contributions in accordance with collective bargaining agreements or participation agreements. Generally, these agreements provide that the employers contribute to the Health Plan at a fixed rate on behalf of each covered employee. For the Health Plan years ended, June 30, 2018 , 2017 and 2016 , the plan received contributions from employers totaling $1.4 billion , $1.3 billion and $1.2 billion , respectively. Our contributions to the Health Plan represent less than 5.0% of total contributions to the plan. Contributions we made to the multi-employer plans for the years ended December 31, 2018 , 2017 and 2016 are included in the table below (in thousands): Benefit Plan 2018 2017 2016 Pension Plan $ 1,819 $ 2,269 $ 2,219 Health Plan 5,667 6,764 6,366 Other plans 683 865 902 Total plan contributions $ 8,169 $ 9,898 $ 9,487

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of December 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. Guarantees During the twelve months ended December 31, 2018 , Ticonderoga Insurance Company, or Ticonderoga, a Vermont licensed captive insurance company and an affiliate of SL Green, became a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Ticonderoga may borrow funds from the FHLBNY in the form of secured advances. As of December 31, 2018 , certain debt and preferred equity investments of the Company were pledged as collateral to secure advances under the FHLBNY facility. If Ticonderoga or SL Green are unable to repay the advances upon the termination of Ticonderoga's membership, the maximum potential amount of future payments the Company could be required to make under the secured advances is $27.5 million . 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 property located at 711 Third Avenue operates under an operating sub-lease with an expiration date of 2033 and five options to renew for an additional 10 years each. The ground rent was reset in July 2011. Following the reset, we were responsible for ground rent payments of $5.25 million annually through July 2016 and then $5.5 million annually thereafter on the 50% portion of the fee that we do not own. The ground rent will reset in July 2021 to the greater of $5.5 million or 7.75% of the fair value of the land. The property located at 461 Fifth Avenue operates under a ground lease ( $2.1 million of ground rent annually) with an expiration date of 2027 and two options to renew for an additional 21 years each, followed by a third option for 15 years. We also have an option to purchase the fee position for a fixed price on a specific date. The property located at 625 Madison Avenue operates under a ground lease ( $4.6 million of ground rent annually) with an expiration date of 2022 and two options to renew for an additional 32 years. The property located at 1185 Avenue of the Americas operates under a ground lease ( $6.9 million of ground rent annually) with an expiration date of 2043. The property located at 1055 Washington Boulevard operates under a ground lease ( $0.6 million of ground rent annually) with an expiration date of 2090. 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 December 31, 2018 (in thousands): Non-cancellable operating leases (1) 2019 $ 19,736 2020 19,736 2021 19,886 2022 17,730 2023 15,424 Thereafter 237,011 Total minimum lease payments $ 329,523 (1) As of December 31, 2018 , the total minimum sublease rentals to be received in the future under non-cancellable subleases is $1.0 billion .

Quarterly Financial Data of the

Quarterly Financial Data of the Company (unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data of the Company (unaudited)	Quarterly Financial Data of the Company (unaudited) Summarized quarterly financial data for the years ended December 31, 2018 and 2017 , was as follows (in thousands): 2018 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 200,239 $ 198,587 $ 211,048 $ 206,229 Total expenses 131,216 128,487 130,334 131,150 Equity in net income (loss) from unconsolidated joint ventures 363 (164 ) 1,252 2,747 Equity in net (loss) gain on sale of interest in unconsolidated joint venture (1 ) 6,345 270 (633 ) (Loss) gain on sale of real estate, net (36,459 ) (2,773 ) (14,863 ) — Purchase price and other fair value adjustments — — — 54,860 Depreciable real estate reserves and impairment (106,376 ) — — — Net income (73,450 ) 73,508 67,373 132,053 Net income attributable to noncontrolling interests in other partnerships (2 ) (212 ) (212 ) (292 ) Preferred units dividend (956 ) (955 ) (955 ) (955 ) Net (loss) income attributable to ROP common unitholder $ (74,408 ) $ 72,341 $ 66,206 $ 130,806 2017 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 241,463 $ 241,908 $ 251,812 $ 232,355 Total expenses 164,490 180,142 167,865 169,206 Equity in net income from unconsolidated joint ventures 3,830 2,927 3,180 4,255 Equity in net gain on sale of interest in unconsolidated joint venture 387 282 — 3 Gain on sale of real estate, net 64,779 114 4,933 — Depreciable real estate reserves and impairment (86,364 ) (379 ) (29,063 ) (56,265 ) Net income 59,605 64,710 62,997 11,142 Net (income) loss attributable to noncontrolling interests in other partnerships (2,147 ) 1,467 18,134 (14 ) Preferred units dividend (956 ) (955 ) (955 ) (953 ) Net income attributable to ROP common unitholder $ 56,502 $ 65,222 $ 80,176 $ 10,175

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information The Company has two reportable segments, real estate and debt and preferred equity investments. We evaluate real estate performance and allocate resources based on earnings contributions. 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 years ended December 31, 2018 , 2017 and 2016 and selected asset information as of December 31, 2018 and 2017 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Years ended: December 31, 2018 $ 625,695 $ 190,408 $ 816,103 December 31, 2017 773,561 193,977 967,538 December 31, 2016 761,314 214,102 975,416 Net Income: Years ended: December 31, 2018 $ 74,460 $ 125,024 $ 199,484 December 31, 2017 27,985 170,469 198,454 December 31, 2016 108,304 204,996 313,300 Total assets As of: December 31, 2018 $ 4,917,674 $ 2,091,623 $ 7,009,297 December 31, 2017 6,182,300 2,359,208 8,541,508 Interest costs for the debt and preferred equity segment include actual costs incurred for borrowings on the 2016 MRA and 2017 MRA. Interest is imputed on the investments that do not collateralize the 2016 MRA or 2017 MRA using our weighted average corporate borrowing cost. We also allocate loan loss reserves, net of recoveries, and transaction related costs to the debt and preferred equity segment. We do not allocate marketing, general and administrative expenses to the debt and preferred equity segment since the use of personnel and resources is dependent on transaction volume between the two segments and varies period over period. In addition, we base performance on the individual segments prior to allocating marketing, general and administrative expenses. There were no transactions between the above two segments.

Schedule II_Valuation and Quali

Schedule II—Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
Valuation and Qualifying Accounts [Abstract]
Schedule II—Valuation and Qualifying Accounts	Schedule II—Valuation and Qualifying Accounts December 31, 2018 (in thousands) Column A Column B Column C Column D Column E Description Balance at Beginning of Year Additions Charged Against Operations/Recovery Uncollectible Accounts Written-off (1) Balance at End of Year Year Ended December 31, 2018 Tenant and other receivables—allowance $ 7,237 $ 3,063 $ (3,505 ) $ 6,795 Deferred rent receivable—allowance 11,189 469 (2,123 ) 9,535 Year Ended December 31, 2017 Tenant and other receivables—allowance $ 4,879 $ 3,657 $ (1,299 ) $ 7,237 Deferred rent receivable—allowance 17,798 2,084 (8,693 ) 11,189 Year Ended December 31, 2016 Tenant and other receivables—allowance $ 5,593 $ 3,604 $ (4,318 ) $ 4,879 Deferred rent receivable—allowance 14,788 3,955 (945 ) 17,798 (1) Includes the effect of properties that were sold and/or deconsolidated within the period.

Schedule III_Real Estate And Ac

Schedule III—Real Estate And Accumulated Depreciation	12 Months Ended
	Dec. 31, 2018
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III—Real Estate And Accumulated Depreciation	Schedule III—Real Estate And Accumulated Depreciation December 31, 2018 (in thousands) Column A Column B Column C Initial Cost Column D Cost Capitalized Subsequent To Acquisition Column E Gross Amount at Which Carried at Close of Period Column F Column G Column H Column I Description Encumbrances Land Building & Improvements Land Building & Improvements Land Building & Improvements Total Accumulated Depreciation Date of Construction Date Acquired Life on Which Depreciation is Computed 810 Seventh Avenue(1) $ — $ 114,077 $ 476,386 $ — $ 74,433 $ 114,077 $ 550,819 $ 664,896 $ 176,354 1970 1/2007 Various 461 Fifth Avenue(1) — — 62,695 — 25,581 — 88,276 88,276 29,680 1988 10/2003 Various 750 Third Avenue(1) — 51,093 205,972 — 45,551 51,093 251,523 302,616 101,854 1958 7/2004 Various 555 W. 57th Street(1) — 18,846 78,704 — 62,242 18,846 140,946 159,792 69,817 1971 1/1999 Various 1185 Avenue of the Americas(1) — — 728,213 — 62,893 — 791,106 791,106 265,896 1969 1/2007 Various 1350 Avenue of the Americas(1) — 91,038 380,744 (97 ) 50,773 90,941 431,517 522,458 136,853 1966 1/2007 Various 100 Summit Lake Drive(2) — 10,526 43,109 (3,337 ) (94 ) 7,189 43,015 50,204 18,936 1988 1/2007 Various 200 Summit Lake Drive(2) — 11,183 47,906 (5,321 ) (9,102 ) 5,862 38,804 44,666 21,203 1990 1/2007 Various 500 Summit Lake Drive(2) — 9,777 39,048 (3,601 ) (7,875 ) 6,176 31,173 37,349 14,523 1986 1/2007 Various 360 Hamilton Avenue(2) — 29,497 118,250 (2,625 ) 8,005 26,872 126,255 153,127 43,901 2000 1/2007 Various 1010 Washington Boulevard(3) — 7,747 30,423 (1,259 ) 2,928 6,488 33,351 39,839 12,489 1988 1/2007 Various 1055 Washington Boulevard(3) — 13,516 53,228 (5,130 ) (9,986 ) 8,386 43,242 51,628 20,382 1987 6/2007 Various 609 Fifth Avenue(1) — 36,677 145,954 — 49,527 36,677 195,481 232,158 43,777 1925 6/2006 Various 110 East 42nd Street(1) — 34,000 46,411 (138 ) 28,673 33,862 75,084 108,946 16,960 1921 5/2011 Various 304 Park Avenue(1) — 54,189 75,619 300 15,024 54,489 90,643 145,132 19,315 1930 6/2012 Various 635 Sixth Avenue(1) — 24,180 37,158 163 51,103 24,343 88,261 112,604 10,931 1902 9/2012 Various 641 Sixth Avenue(1) — 45,668 67,316 308 9,760 45,976 77,076 123,052 15,891 1902 9/2012 Various 315 West 33rd Street(1) 250,000 195,834 164,429 — 15,133 195,834 179,562 375,396 25,397 2000-2001 11/2013 Various Williamsburg(4) — 3,677 14,708 2,523 (4,550 ) 6,200 10,158 16,358 2,127 2010 12/2010 Various 115 Spring Street(1) 65,550 11,078 44,799 — 1,850 11,078 46,649 57,727 5,248 1900 7/2014 Various 125 Park Avenue(1) — 120,900 189,714 — 80,884 120,900 270,598 391,498 77,542 1923 10/2010 Various 625 Madison Ave(1) — — 246,673 — 44,646 — 291,319 291,319 118,380 1956 10/2004 Various 711 Third Avenue(1)(5) — 19,844 42,499 — 73,270 19,844 115,769 135,613 45,066 1955 5/1998 Various 752 Madison Avenue(1) — 282,415 — 1,871 1,124 284,286 1,124 285,410 12 1996/2012 1/2012 N/A 110 Greene Street(1)(6) — 45,120 215,470 — 12,923 45,120 228,393 273,513 23,683 1910 7/2015 Various Other(7) — 1,130 — (1,134 ) 4,691 (4 ) 4,691 4,687 — Various $ 315,550 $ 1,232,012 $ 3,555,428 $ (17,477 ) $ 689,407 $ 1,214,535 $ 4,244,835 $ 5,459,370 $ 1,316,217 __________________________________________________________________ (1) Property located in New York, New York. (2) Property located in Westchester County, New York. (3) Property located in Connecticut. (4) Property located in Brooklyn, New York. (5) We own a tenancy in common interest in the property. (6) We own a 90% interest in this property. (7) Other includes tenant improvements, capitalized interest and corporate improvements. The changes in real estate for the years ended December 31, 2018 , 2017 and 2016 are as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 7,029,455 $ 7,508,870 $ 7,428,243 Acquisitions — — — Improvements 133,946 121,959 123,173 Retirements/disposals (1,704,031 ) (601,374 ) (42,546 ) Balance at end of year $ 5,459,370 $ 7,029,455 $ 7,508,870 The aggregate cost of land, buildings and improvements, before depreciation, for Federal income tax purposes at December 31, 2018 was approximately $4.2 billion (unaudited). The changes in accumulated depreciation, exclusive of amounts relating to equipment, autos, and furniture and fixtures, for the years ended December 31, 2018 , 2017 and 2016 , are as follows (in thousands): 2018 2017 2016 Balance at beginning of year $ 1,492,603 $ 1,437,222 $ 1,267,598 Depreciation for year 146,216 178,801 183,873 Retirements/disposals (322,602 ) (123,420 ) (14,249 ) Balance at end of year $ 1,316,217 $ 1,492,603 $ 1,437,222

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 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. A noncontrolling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to us. Noncontrolling interests are required to be presented as a separate component of equity in the consolidated balance sheet and the presentation of net income is modified to present earnings and other comprehensive income attributed to controlling and noncontrolling interests. We assess the accounting treatment for each joint venture and debt and preferred equity investment. This assessment includes a review of each joint venture or limited liability company agreement to determine the rights provided to each party and whether those rights are protective or participating. For all VIEs, we review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity's economic performance. In situations where we and our partner approve, among other things, the annual budget, receive a detailed monthly reporting package, meet on a quarterly basis to review the results of the joint venture, review and approve the joint venture's tax return before filing, and approve all leases that cover more than a nominal amount of space relative to the total rentable space at each property, we do not consolidate the joint venture as we consider these to be substantive participation rights that result in shared power of the activities that most significantly impact the performance of the joint venture. Our joint venture agreements typically contain certain protective rights such as requiring partner approval to sell, finance or refinance the property and the payment of capital expenditures and operating expenditures outside of the approved budget or operating plan.
Investment in Commercial Real Estate Properties	On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be 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 and depreciation expense is no longer recorded. Investment in Commercial Real Estate Properties Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their respective fair values on the acquisition date. When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of operations. See Note 3, "Property Acquisitions." We allocate the purchase price of real estate to land and building (inclusive of tenant improvements) and, if determined to be material, intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases. We depreciate the amount allocated to building (inclusive of tenant improvements) over their estimated useful lives, which generally range from three to 40 years . We amortize the amount allocated to the above- and below-market leases over the remaining term of the associated lease, which generally range from one to 14 years , and record it as either an increase (in the case of below-market leases) or a decrease (in the case of above-market leases) to rental income. We amortize the amount allocated to the values associated with in-place leases over the expected term of the associated lease, which generally ranges from one to 14 years . If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The tenant improvements and origination costs are amortized as an expense over the remaining life of the lease (or charged against earnings if the lease is terminated prior to its contractual expiration date). We assess fair value of the leases based on estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. To the extent acquired leases contain fixed rate renewal options that are below-market and determined to be material, we amortize such below-market lease value into rental income over the renewal period. As of December 31, 2018 , the weighted average amortization period for above-market leases, below-market leases, and in-place lease costs is 4.2 years, 7.7 years, and 4.6 years, respectively. We incur a variety of costs in the development and leasing of our properties. After the determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year after major construction activity ceases. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction. Properties are depreciated using the straight-line method over the estimated useful lives of the assets.
Cash and Cash Equivalents	Cash and Cash Equivalents We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents.
Restricted Cash	Restricted Cash Restricted cash primarily consists of security deposits held on behalf of our tenants, interest reserves, as well as capital improvement and real estate tax escrows required under certain loan agreements.
Investment in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity in net income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture and includes adjustments related to basis differences that were identified as part of the initial accounting for the investment. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us. See Note 6, "Investments in Unconsolidated Joint Ventures." We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at December 31, 2018 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some of the residual profit from such projects. When the risk and rewards of these arrangements are essentially the same as an investor or joint venture partner, we account for these arrangements as real estate investments under the equity method of accounting for investments. Otherwise, we account for these arrangements consistent with the accounting for our debt and preferred equity investments.
Deferred Lease Costs	Deferred Lease Costs Deferred lease costs consist of fees and direct costs incurred to execute operating leases and are amortized on a straight-line basis over the related lease term.
Deferred Financing Costs	Deferred Financing Costs Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close. Deferred financing costs related to a recognized debt liability are presented in the balance sheet as a direct deduction from the carrying amount of that debt liability.
Revenue Recognition	Investment income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt. Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as an adjustment to interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cash flows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield. Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received. We may syndicate a portion of the loans that we originate or sell the loans individually. When a transaction meets the criteria for sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, original issue discounts, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of operations. Any fees received at the time of sale or syndication are recognized as part of investment income. Asset management fees are recognized on a straight-line basis over the term of the asset management agreement. Revenue Recognition Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance. In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required.
Rent Expense	Rent Expense Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred lease payable on the consolidated balance sheets.
Exchangeable Debt Instruments	Exchangeable Debt Instruments The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, are bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate the liability component of exchangeable debt based on the present value of the contractual cash flows discounted at our comparable market conventional debt borrowing rate at the date of issuance. The difference between the principal amount and the fair value of the liability component is reported as a discount on the exchangeable debt that is accreted as additional interest expense from the issuance date through the contractual maturity date using the effective interest method. A portion of this additional interest expense may be capitalized to the development and redevelopment balances qualifying for interest capitalization each period. The liability component of the exchangeable debt is reported net of discounts on our consolidated balance sheets. We calculate the equity component of exchangeable debt based on the difference between the initial proceeds received from the issuance of the exchangeable debt and the fair value of the liability component at the issuance date. The equity component is included in additional paid-in-capital, net of issuance costs, on our consolidated balance sheets. We allocate issuance costs for exchangeable debt between the liability and the equity components based on their relative values.
Income Taxes	Income Taxes SL Green is taxed as a REIT under Section 856(c) of the Code. As a REIT, SL Green generally is not subject to Federal income tax. To maintain its qualification as a REIT, SL Green must distribute at least 90% of its REIT taxable income to its stockholders and meet certain other requirements. If SL Green fails to qualify as a REIT in any taxable year, SL Green will be subject to Federal income tax on its taxable income at regular corporate rates. SL Green may also be subject to certain state, local and franchise taxes. Under certain circumstances, Federal income and excise taxes may be due on its undistributed taxable income. 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. We follow a two-step approach for evaluating uncertain tax positions. Recognition (step one) occurs when an enterprise concludes that a tax position, based solely on its technical merits, is more-likely-than-not to be sustained upon examination. Measurement (step two) determines the amount of benefit that is more-likely-than-not to be realized upon settlement. Derecognition of a tax position that was previously recognized would occur when a company subsequently determines that a tax position no longer meets the more-likely-than-not threshold of being sustained. The use of a valuation allowance as a substitute for derecognition of tax positions is prohibited. On December 22, 2017, the Tax Cuts and Jobs Act (the ‘‘Tax Act’’) was signed into law and makes substantial changes to the Code. The Tax Act has not had a material impact on our financial statements for the years ended December 31, 2018 or December 31, 2017 .
Derivative Instruments	Derivative Instruments In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collars and floors, to manage, or hedge, interest rate risk. Effectiveness is essential for those derivatives that we intend to qualify for hedge accounting. Some derivative instruments are associated with an anticipated transaction. In those cases, hedge effectiveness criteria also require that it be probable that the underlying transaction occurs. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract. To determine the fair values of derivative instruments, we use a variety of methods and assumptions that are based on market conditions and risks existing at each balance sheet date. For the majority of financial instruments including most derivatives, long-term investments and long-term debt, standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost, and termination cost are used to determine fair value. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized. In the normal course of business, we are exposed to the effect of interest rate changes and limit these risks by following established risk management policies and procedures including the use of derivatives. To address exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices and manage the cost of borrowing obligations. We use a variety of conventional derivative products. These derivatives typically include interest rate swaps, caps, collars and floors. We expressly prohibit the use of unconventional derivative instruments and using derivative instruments for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors. We may employ swaps, forwards or purchased options to hedge qualifying forecasted transactions. Gains and losses related to these transactions are deferred and recognized in net income as interest expense in the same period or periods that the underlying transaction occurs, expires or is otherwise terminated. Hedges that are reported at fair value and presented on the balance sheet could be characterized as cash flow hedges or fair value hedges. Interest rate caps and collars are examples of cash flow hedges. Cash flow hedges address the risk associated with future cash flows of interest payments. For all hedges held by us and which were deemed to be fully effective in meeting the hedging objectives established by our corporate policy governing interest rate risk management, no net gains or losses were reported in earnings. The changes in fair value of hedge instruments are reflected in accumulated other comprehensive income. For derivative instruments not designated as hedging instruments, the gain or loss, resulting from the change in the estimated fair value of the derivative instruments, is recognized in current earnings during the period of change.
Shares Contributed by Parent Company	Shares Contributed by Parent Company We record contributed shares of SL Green common stock as a reduction to general partner's capital in our financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash investments, debt and preferred equity investments and accounts receivable. We place our cash investments with high quality financial institutions. The collateral securing our debt and preferred equity investments is located in 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.
Reclassification	Reclassification Certain prior year balances have been reclassified to conform to our current year presentation
Accounting Standards Updates	Accounting Standards Updates
Fair Value Measurements	Fair Value Measurements We are required to disclose fair value information with regard to our financial instruments, whether or not recognized in the consolidated balance sheets, for which it is practical to estimate fair value. The FASB guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. We measure and/or disclose the estimated fair value of financial assets and liabilities based on a hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity and the reporting entity’s own assumptions about market participant assumptions. This hierarchy consists of three broad levels: Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date; Level 2 - inputs other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly; and Level 3 - unobservable inputs for the asset or liability that are used when little or no market data is available. We follow this hierarchy for our assets and liabilities measured at fair value on a recurring and nonrecurring basis. In instances in which the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level of input that is significant to the fair value measurement in its entirety. Our assessment of the significance of the particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability. The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2018 and 2017 (in thousands): December 31, 2018 Total Level 1 Level 2 Level 3 Assets: Interest rate cap and swap agreements (included in other assets) $ — $ — $ — $ — December 31, 2017 Total Level 1 Level 2 Level 3 Assets: Interest rate cap and swap agreements (included in other assets) $ 167 $ — $ 167 $ — We determine 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 December 2018, the Company determined that it was more likely than not that its suburban properties would be sold or otherwise disposed of significantly before the end of their previously estimated useful life. The Company tested the recoverability of the assets and, as a result of the carrying amount of the assets not being deemed recoverable and exceeding their fair value as measured on a asset by asset basis, recorded a $106.4 million impairment loss. These charges are included in depreciable real estate reserves and impairment in the consolidated statement of operations. The fair value of the assets were determined 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 Pre_2

Organization and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of December 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 Properties Approximate Square Feet (unaudited) Weighted Average (1) (unaudited) Commercial: Manhattan Office (2) 15 8,303,245 94.9 % Retail (3)(4) 5 364,816 99.4 % Development/Redevelopment 1 160,000 96.0 % 21 8,828,061 95.1 % Suburban Office 6 1,432,400 94.3 % Retail 1 52,000 100.0 % 7 1,484,400 94.5 % Total commercial properties 28 10,312,461 95.0 % Residential: Manhattan Residential (3) — 222,855 96.1 % Total portfolio 28 10,535,316 95.0 % ____________________________________________________________________ (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 December 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 (unaudited).

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Schedule of estimated useful lives	Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows: Category Term Building (fee ownership) 40 years Building improvements shorter of remaining life of the building or useful life Building (leasehold interest) lesser of 40 years or remaining term of the lease Property under capital lease remaining lease term Furniture and fixtures four to seven years Tenant improvements shorter of remaining term of the lease or useful life
Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)	The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Identified intangible assets (included in other assets): Gross amount $ 213,421 $ 276,163 Accumulated amortization (201,010 ) (236,737 ) Net (1) $ 12,411 $ 39,426 Identified intangible liabilities (included in deferred revenue): Gross amount $ 230,275 $ 496,438 Accumulated amortization (216,362 ) (366,091 ) Net (1) $ 13,913 $ 130,347 (1) As of December 31, 2018, no net intangible assets and no net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale. As of December 31, 2017, $0.1 million net intangible assets and $0.1 million net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale.
Schedule of estimated annual amortization of acquired below-market leases, net of acquired above-market leases	The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands): 2019 $ (5,166 ) 2020 (4,398 ) 2021 (1,495 ) 2022 (1,192 ) 2023 (633 )
Schedule of estimated annual amortization of all other identifiable assets	The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands): 2019 $ 5,486 2020 4,728 2021 3,376 2022 1,813 2023 1,453
Schedule of concentration of credit risk	For the years ended December 31, 2018 , 2017, and 2016, the following properties contributed more than 5.0% of our annualized cash rent, including our share of joint venture annualized cash rent: Property 2018 Property 2017 Property 2016 1185 Avenue of the Americas 14.9% 1185 Avenue of the Americas 15.6% 1185 Avenue of the Americas 14.8% 625 Madison Avenue 10.9% 625 Madison Avenue 10.2% 625 Madison Avenue 9.6% 919 Third Avenue 8.6% 919 Third Avenue 8.3% 919 Third Avenue 8.1% 750 Third Avenue 8.4% 750 Third Avenue 8.0% 750 Third Avenue 7.7% 810 Seventh Avenue 8.4% 810 Seventh Avenue 8.0% 810 Seventh Avenue 7.3% 555 West 57th Street 7.5% 555 West 57th Street 6.9% 555 West 57th Street 6.6% 125 Park Avenue 7.3% 125 Park Avenue 6.8% 125 Park Avenue 6.6% 1350 Avenue of the Americas 7.1% 1350 Avenue of the Americas 6.8% 1350 Avenue of the Americas 6.4% 711 Third Avenue 5.9% 711 Third Avenue 5.1% 711 Third Avenue 5.2%

Properties Held for Sale and _2

Properties Held for Sale and Property Dispositions (Tables)	12 Months Ended
	Dec. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Schedule of properties sold and income from discontinued operations	The following table summarizes the properties sold during the years ended December 31, 2018 , 2017 and 2016 : Property Disposition Date Property Type (unaudited) Approximate Usable Square Feet Sales Price (1) (in millions) Gain (Loss) on Sale (2) (in millions) 400 Summit Lake Drive November 2018 Land 39.5 acres $ 3.0 $ (36.2 ) 1-6 International Drive July 2018 Office 540,000 55.0 (2.6 ) 635 Madison Avenue June 2018 Retail 176,530 153.0 (14.1 ) 115-117 Stevens Avenue May 2018 Office 178,000 12.0 (0.7 ) 125 Chubb Way October 2017 Office 278,000 29.5 (26.1 ) 16 Court Street October 2017 Office 317,600 171.0 64.9 680-750 Washington Boulevard July 2017 Office 325,000 97.0 (44.2 ) 520 White Plains Road April 2017 Office 180,000 21.0 (14.6 ) 102 Greene Street (3) April 2017 Retail 9,200 43.5 4.9 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) (1) Sales price represents the actual sales price for an entire property or the gross asset valuation for interests in a property. (2) The gain on sale for 16 Court Street and 102 Greene Street are net of $2.5 million and $0.9 million , respectively, in employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In April 2017, we closed on the sale of a 90 % interest 102 Greene Street and had subsequently accounted for our interest in the property as an investment in unconsolidated joint ventures. We sold the remaining 10 % interest in September 2017. See Note 6, "Investments in Unconsolidated Joint Ventures."

Debt and Preferred Equity Inv_2

Debt and Preferred Equity Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Rollforward of debt and preferred equity investments	Below is a summary of the activity relating to our debt and preferred equity investments as of December 31, 2018 and 2017 (in thousands): December 31, 2018 December 31, 2017 Balance at beginning of period (1) $ 2,114,041 $ 1,640,412 Debt investment originations/accretion (2) 834,304 1,142,591 Preferred equity investment originations/accretion (2) 8,430 144,456 Redemptions/sales/syndications/amortization (3) (994,906 ) (813,418 ) Net change in loan loss reserves (5,750 ) — Balance at end of period (1) $ 1,956,119 $ 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 and are included in other assets and other liabilities on the consolidated balance sheets
Rollforward of total allowance for loan loss reserves	The following table is a rollforward of our total loan loss reserves at December 31, 2018 , 2017 and 2016 (in thousands): December 31, 2018 2017 2016 Balance at beginning of year $ — $ — $ — Expensed 5,750 — — Recoveries — — — Charge-offs and reclassifications — — — Balance at end of period $ 5,750 $ — $ —
Schedule of debt investments	As of December 31, 2018 and 2017 , we held the following debt investments with an aggregate weighted average current yield of 8.99% , at December 31, 2018 (in thousands): Loan Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior Financing December 31, 2018 Carrying Value (1) December 31, 2017 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Mezzanine Loan (3a) $ — $ 1,160,000 $ 213,185 $ 204,005 March 2020 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 147,000 24,932 24,913 April 2022 Mezzanine Loan — 280,000 36,585 34,600 August 2022 Mezzanine Loan — 85,097 12,706 12,699 November 2023 Mezzanine Loan — 180,000 30,000 — December 2023 Mezzanine Loan (3b) — 115,000 12,941 12,932 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 340,000 11,000 15,000 November 2026 Mezzanine Loan — 1,712,750 55,250 55,250 June 2027 Mortgage/Jr. Mortgage Loan (4) — — — 250,464 Mortgage Loan (5) — — — 26,366 Mortgage Loan (5) — — — 239 Loan Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior Financing December 31, 2018 Carrying Value (1) December 31, 2017 Carrying Value (1) Maturity Date (2) Total fixed rate $ — $ 4,129,847 $ 430,099 $ 669,968 Floating Rate Investments: Mezzanine Loan (6) $ — $ 45,025 $ 37,499 $ 34,879 January 2019 Mezzanine Loan (3c)(7) — 85,000 15,333 15,381 March 2019 Mezzanine Loan (3d)(7) — 65,000 14,822 14,869 March 2019 Mezzanine Loan (9) — 38,000 21,990 21,939 March 2019 Mezzanine Loan (8) — 40,000 19,986 19,982 April 2019 Mezzanine Loan — 265,000 24,961 24,830 April 2019 Mortgage/Jr. Mortgage Participation Loan 40,530 233,086 84,012 71,832 August 2019 Mezzanine Loan (8)(9) — 65,000 14,998 14,955 August 2019 Mortgage/Mezzanine Loan (8) — — 19,999 19,940 August 2019 Mortgage/Mezzanine Loan 1,027 — 154,070 143,919 September 2019 Mezzanine Loan — 350,000 34,886 34,737 October 2019 Mortgage/Mezzanine Loan (10) 7,243 — 62,493 43,845 January 2020 Mezzanine Loan (10) 559 575,955 79,164 75,834 January 2020 Mortgage Loan 11,204 — 88,501 — February 2020 Mezzanine Loan 1,277 322,300 53,402 — March 2020 Mortgage/Mezzanine Loan 14,860 — 277,694 — April 2020 Mortgage/Mezzanine Loan (8) — — 37,094 — June 2020 Mezzanine Loan 7,887 38,167 12,627 11,259 July 2020 Mortgage/Mezzanine Loan — — 83,449 — October 2020 Mezzanine Loan 38,575 362,908 88,817 75,428 November 2020 Mortgage/Mezzanine Loan 33,131 — 98,804 88,989 December 2020 Mortgage/Mezzanine Loan — — 35,266 35,152 December 2020 Jr. Mortgage Participation/Mezzanine Loan — 60,000 15,665 15,635 July 2021 Mezzanine Loan (9) — 38,596 7,305 34,947 December 2021 Mortgage/Mezzanine Loan (5) — — — 162,553 Mortgage/Mezzanine Loan (5) — — — 74,755 Mortgage/Mezzanine Loan (11) — — — 23,609 Mortgage/Mezzanine Loan (5) — — — 16,969 Mezzanine Loan (5) — — — 59,723 Mezzanine Loan (5) — — — 37,851 Mezzanine Loan (5) — — — 14,855 Mezzanine Loan (9) — — — 12,174 Mezzanine Loan (9) — — — 10,934 Mezzanine Loan (5) — — — 37,250 Mezzanine Loan (5) — — — 15,148 Mezzanine Loan (5) — — — 8,550 Mezzanine Loan (9) — — — 26,927 Total floating rate $ 156,293 $ 2,584,037 $ 1,382,837 $ 1,299,650 Total $ 156,293 $ 6,713,884 $ 1,812,936 $ 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) 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 , and (d) $14.1 million . (4) These loans were conveyed to SL Green in the form of a distribution in 2018. (5) This loan was repaid in 2018. (6) As of January 2019, this loan is in maturity default. No impairment was recorded as the Company believes that the fair value of the property exceeded the carrying amount of the loans. (7) This loan was extended in 2019. (8) This loan was extended in 2018. (9) This loan was repaid in 2019. (10) This loan was modified in 2019. (11) This loan was sold in 2018.
Schedule of preferred equity investments	As of December 31, 2018 and 2017 , we held the following preferred equity investments with an aggregate weighted average current yield of 5.80% at December 31, 2018 (in thousands): Type December 31, 2018 Future Funding Obligations December 31, 2018 Senior December 31, 2018 (1) December 31, 2017 (1) Mandatory Redemption (2) Preferred Equity $ — $ 272,000 $ 143,183 $ 144,423 April 2021 $ — $ 272,000 $ 143,183 $ 144,423 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options.

Investments in Unconsolidated_2

Investments in Unconsolidated Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Schedule of investment in real estate joint venture	The table below provides general information on each of our joint ventures as of December 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 (4) Invesco Real Estate 20.00% 20.00% 68,342 August 2015 $ 277,750 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of December 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 January 2019, we closed on the sale of our interest in this property to our joint venture partner. The transaction generated net cash proceeds to the Company of $15.2 million . The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2018 , 2017 , and 2016 : Property Ownership Interest Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) (Loss) Gain on Sale (in thousands) (2) 2 Herald Square (3) 49.00% November 2018 Ownership Interest $ 265,000 $ — Mezzanine Loan (4) 33.33% August 2018 Repayment 15,000 N/A 102 Greene Street 10.00% September 2017 Ownership Interest 43,500 283 76 11th Avenue (5) 33.33% May 2017 Repayment 138,240 N/A (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. As of December 31, 2018 and 2017 , the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type December 31, 2018 December 31, 2017 Maturity Date Mezzanine Loan and Preferred Equity (1) $ — $ 100,000 Mezzanine Loan (2) — 26,716 $ — $ 126,716 (1) The mezzanine loan was repaid and the preferred equity interest was redeemed in March 2018. (2)
Schedule of first mortgage notes and other loans payable on joint venture properties	The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2018 and 2017 , respectively, are as follows (amounts in thousands): Property Economic Interest (1) Maturity Date Interest Rate (2) December 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 (3) 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 (1,754 ) (2,862 ) Total joint venture mortgages and other loans payable, net $ 639,246 $ 138,138 (1) Economic interest represents the Company's interests in the joint venture as of December 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 December 31, 2018 . Floating rate debt is presented with the stated interest rate spread over 30-day LIBOR, unless otherwise specified.
Combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at December 31, 2018 and 2017 are as follows (in thousands): December 31, 2018 December 31, 2017 Assets Commercial real estate property, net $ 1,802,698 $ 273,116 Debt and preferred equity investments, net — 141,716 Other assets 479,005 15,735 Total assets $ 2,281,703 $ 430,567 Liabilities and members' equity Mortgages and other loans payable, net $ 639,246 $ 138,138 Other liabilities 608,469 18,908 Members' equity 1,033,988 273,521 Total liabilities and members' equity $ 2,281,703 $ 430,567 Company's investments in unconsolidated joint ventures $ 339,302 $ 130,217
Combined statements of operations for the unconsolidated joint ventures	The combined statements of operations for the unconsolidated joint ventures for the years ended December 31, 2018 , 2017 , and 2016 are as follows (in thousands): Year Ended December 31, 2018 2017 2016 Total revenues $ 147,411 $ 35,204 $ 38,524 Operating expenses 24,977 877 1,238 Real estate taxes 30,462 1,389 1,192 Ground rent 1,851 — — Interest expense, net of interest income 32,849 3,769 2,895 Amortization of deferred financing costs 1,108 1,114 1,108 Depreciation and amortization 50,468 8,405 8,404 Total expenses $ 141,715 $ 15,554 $ 14,837 Net income $ 5,696 $ 19,650 $ 23,687 Company's equity in net income from unconsolidated joint ventures $ 4,198 $ 14,192 $ 14,509 (1) The combined statements of operations 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 Pay_2

Mortgages and Other Loans Payable (Tables)	12 Months Ended
	Dec. 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 December 31, 2018 and 2017 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) December 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 2019 L+ 2.34% $ 300,000 $ 90,809 115 Spring Street September 2023 L+ 3.40% 65,550 — Total mortgages and other loans payable $ 615,550 $ 840,809 Deferred financing costs, net of amortization (7,981 ) (11,161 ) Total mortgages and other loans payable, net $ 607,569 $ 829,648 (1) Interest rate as of December 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)	12 Months Ended
	Dec. 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 December 31, 2018 and 2017 , respectively, by scheduled maturity date (dollars in thousands): Issuance December 31, 2018 Unpaid Principal Balance December 31, 2018 Accreted Balance December 31, 2017 Accreted Balance Coupon Initial Term Maturity Date March 16, 2010 (1) (4) $ — $ — $ 250,000 November 15, 2012 (2) (4) — — 305,163 December 17, 2015 (1) (4) — — 100,000 August 5, 2011 (1) (3) — — 249,953 $ — $ — $ 905,116 Deferred financing costs, net — — (4,049 ) $ — $ — $ 901,067
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 as of December 31, 2018 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Principal Total Joint Venture Debt 2019 $ — $ — $ — $ — 2020 — 300,000 300,000 28,200 2021 — — — — 2022 — — — — 2023 — 65,550 65,550 255,000 Thereafter — 250,000 250,000 — $ — $ 615,550 $ 615,550 $ 283,200
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Year Ended December 31, 2018 2017 2016 Interest expense before capitalized interest $ 67,647 $ 124,507 $ 110,393 Interest capitalized (5,560 ) (533 ) (1,171 ) Interest income (6 ) (5 ) (14 ) Interest expense, net $ 62,081 $ 123,969 $ 109,208

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 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 December 31, 2018 and December 31, 2017 (in thousands): December 31, 2018 December 31, 2017 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,956,119 (2) $ 2,114,041 (2) Fixed rate debt $ 250,000 $ 249,919 $ 1,655,116 $ 1,715,501 Variable rate debt 365,550 374,387 90,809 92,087 $ 615,550 $ 624,306 $ 1,745,925 $ 1,807,588 (1) Amounts exclude net deferred financing costs. (2) At December 31, 2018 , debt and preferred equity investments had an estimated fair value ranging between $2.0 billion and $2.2 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_ Deriva_2

Financial Instruments: Derivatives and Hedging (Tables)	12 Months Ended
	Dec. 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 years ended December 31, 2018 , 2017 , and 2016 , respectively (in thousands): Amount of Loss Recognized in Other Comprehensive Loss (Effective Portion) Location of Loss Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion) Location of Gain Recognized in Income on Derivative Amount of Gain Recognized into Income (Ineffective Portion) Year Ended December 31, Year Ended December 31, Year Ended December 31, Derivative 2018 2017 2016 2018 2017 2016 2018 2017 2016 Interest Rate Swap $ — $ — $ (13 ) Interest expense $ — $ 359 $ 611 Interest expense $ — $ — $ 3

Rental Income (Tables)

Rental Income (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Schedule of approximate future minimum rents to be received over the next five years and thereafter	Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2018 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands): Consolidated Properties Unconsolidated Properties 2019 $ 514,204 $ 45,500 2020 463,658 44,765 2021 412,040 47,595 2022 373,056 32,693 2023 328,287 32,759 Thereafter 1,362,314 250,340 $ 3,453,559 $ 453,652

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Schedule of contributions made to multi-employer plans	Contributions we made to the multi-employer plans for the years ended December 31, 2018 , 2017 and 2016 are included in the table below (in thousands): Benefit Plan 2018 2017 2016 Pension Plan $ 1,819 $ 2,269 $ 2,219 Health Plan 5,667 6,764 6,366 Other plans 683 865 902 Total plan contributions $ 8,169 $ 9,898 $ 9,487

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 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 December 31, 2018 (in thousands): Non-cancellable operating leases (1) 2019 $ 19,736 2020 19,736 2021 19,886 2022 17,730 2023 15,424 Thereafter 237,011 Total minimum lease payments $ 329,523 (1) As of December 31, 2018 , the total minimum sublease rentals to be received in the future under non-cancellable subleases is $1.0 billion .

Quarterly Financial Data of t_2

Quarterly Financial Data of the Company (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Summarized quarterly financial data	Summarized quarterly financial data for the years ended December 31, 2018 and 2017 , was as follows (in thousands): 2018 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 200,239 $ 198,587 $ 211,048 $ 206,229 Total expenses 131,216 128,487 130,334 131,150 Equity in net income (loss) from unconsolidated joint ventures 363 (164 ) 1,252 2,747 Equity in net (loss) gain on sale of interest in unconsolidated joint venture (1 ) 6,345 270 (633 ) (Loss) gain on sale of real estate, net (36,459 ) (2,773 ) (14,863 ) — Purchase price and other fair value adjustments — — — 54,860 Depreciable real estate reserves and impairment (106,376 ) — — — Net income (73,450 ) 73,508 67,373 132,053 Net income attributable to noncontrolling interests in other partnerships (2 ) (212 ) (212 ) (292 ) Preferred units dividend (956 ) (955 ) (955 ) (955 ) Net (loss) income attributable to ROP common unitholder $ (74,408 ) $ 72,341 $ 66,206 $ 130,806 2017 Quarter Ended December 31 September 30 June 30 March 31 Total revenues $ 241,463 $ 241,908 $ 251,812 $ 232,355 Total expenses 164,490 180,142 167,865 169,206 Equity in net income from unconsolidated joint ventures 3,830 2,927 3,180 4,255 Equity in net gain on sale of interest in unconsolidated joint venture 387 282 — 3 Gain on sale of real estate, net 64,779 114 4,933 — Depreciable real estate reserves and impairment (86,364 ) (379 ) (29,063 ) (56,265 ) Net income 59,605 64,710 62,997 11,142 Net (income) loss attributable to noncontrolling interests in other partnerships (2,147 ) 1,467 18,134 (14 ) Preferred units dividend (956 ) (955 ) (955 ) (953 ) Net income attributable to ROP common unitholder $ 56,502 $ 65,222 $ 80,176 $ 10,175

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected consolidated results of operations for the years ended December 31, 2018 , 2017 and 2016 and selected asset information as of December 31, 2018 and 2017 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues: Years ended: December 31, 2018 $ 625,695 $ 190,408 $ 816,103 December 31, 2017 773,561 193,977 967,538 December 31, 2016 761,314 214,102 975,416 Net Income: Years ended: December 31, 2018 $ 74,460 $ 125,024 $ 199,484 December 31, 2017 27,985 170,469 198,454 December 31, 2016 108,304 204,996 313,300 Total assets As of: December 31, 2018 $ 4,917,674 $ 2,091,623 $ 7,009,297 December 31, 2017 6,182,300 2,359,208 8,541,508

Organization and Basis of Pre_3

Organization and Basis of Presentation (Details) $ in Billions	12 Months Ended
	Dec. 31, 2018USD ($)ft²property
Real estate properties
Percentage of ownership in SL Green Operating Partnership owned by SL Green Realty Corp (as a percent)	95.30%
Number of Properties | property	28
Approximate Square Feet (unaudited)	10,535,316
Weighted Average Occupancy (unaudited)	95.00%
Mortgage loans on real estate, commercial and consumer, net including debt investments, other | $	$ 2
Suburban
Real estate properties
Number of Properties | property	7
Approximate Square Feet (unaudited)	1,484,400
Weighted Average Occupancy (unaudited)	94.50%
Office(2) | Manhattan
Real estate properties
Number of Properties | property	15
Approximate Square Feet (unaudited)	8,303,245
Weighted Average Occupancy (unaudited)	94.90%
Office(2) | Suburban
Real estate properties
Number of Properties | property	6
Approximate Square Feet (unaudited)	1,432,400
Weighted Average Occupancy (unaudited)	94.30%
Retail | 919 Third Avenue
Real estate properties
Approximate Square Feet (unaudited)	1,454,000
Retail | 131-137 Spring Street
Real estate properties
Approximate Square Feet (unaudited)	68,342
Number of properties held for sale | property	2
Retail | Manhattan
Real estate properties
Number of Properties | property	5
Approximate Square Feet (unaudited)	364,816
Weighted Average Occupancy (unaudited)	99.40%
Retail | Suburban
Real estate properties
Number of Properties | property	1
Approximate Square Feet (unaudited)	52,000
Weighted Average Occupancy (unaudited)	100.00%
Development Properties | Manhattan
Real estate properties
Number of Properties | property	1
Approximate Square Feet (unaudited)	160,000
Weighted Average Occupancy (unaudited)	96.00%
Commercial Properties
Real estate properties
Number of Properties | property	28
Approximate Square Feet (unaudited)	10,312,461
Weighted Average Occupancy (unaudited)	95.00%
Commercial Properties | Manhattan
Real estate properties
Number of Properties | property	21
Approximate Square Feet (unaudited)	8,828,061
Weighted Average Occupancy (unaudited)	95.10%
Residential | Manhattan
Real estate properties
Number of Properties | property	0
Approximate Square Feet (unaudited)	222,855
Weighted Average Occupancy (unaudited)	96.10%
Consolidated Properties | Dual property type, retail portion | Manhattan
Real estate properties
Approximate Square Feet (unaudited)	270,132
Consolidated Properties | Dual property type, residential portion | Manhattan
Real estate properties
Approximate Square Feet (unaudited)	222,855

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details) - USD ($)		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Investment in Commercial Real Estate Properties
Weighted average amortization period, above-market leases (in years)		4 years 2 months 6 days
Weighted average amortization period, below-market leases (in years)		7 years 8 months 1 day
Weighted average amortization period, in-place leases (in years)		4 years 7 months 1 day
Maximum period of cessation of major construction activity to completion of construction project (in years)		1 year
Depreciation expense (including amortization of capital lease asset)		$ 150,800,000	$ 188,900,000	$ 196,200,000
Rental revenue from amortization of acquired leases		6,700,000	17,000,000	$ 20,200,000
Assets	[1]	7,009,297,000	8,541,508,000
Identified intangible assets (included in other assets):
Gross amount		213,421,000	276,163,000
Accumulated amortization		(201,010,000)	(236,737,000)
Net		12,411,000	39,426,000
Identified intangible liabilities (included in deferred revenue):
Gross amount		230,275,000	496,438,000
Accumulated amortization		(216,362,000)	(366,091,000)
Net		13,913,000	130,347,000
Net intangible assets reclassified to assets held for sale		0	100,000
Net intangible liabilities reclassified to liabilities related to assets held for sale		$ 0	$ 100,000
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 Fee Ownership
Investment in Commercial Real Estate Properties
Estimated useful life (years)		40 years
Building (leasehold interest) | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (years)		40 years
Furniture and fixtures | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life (years)		4 years
Furniture and fixtures | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (years)		7 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
Scenario, Forecast | Accounting Standards Update 2016-02 | Minimum
Investment in Commercial Real Estate Properties
Assets					$ 0
Scenario, Forecast | Accounting Standards Update 2016-02 | Maximum
Investment in Commercial Real Estate Properties
Assets					$ 200,000,000
[1]	The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs: $268.6 million and $297.3 million of land, $1.3 billion and $1.4 billion of building and improvements, $319.1 million and $318.4 million of accumulated depreciation, $143.9 million and $160.5 million of other assets included in other line items, $495.0 million and $494.0 million of real estate debt, net, $2.1 million and $2.1 million of accrued interest payable, and $48.8 million and $61.4 million of other liabilities included in other line items as of December 31, 2017 and December 31, 2016, respectively.

Significant Accounting Polici_5

Significant Accounting Policies - Estimated Annual Amortization and Revenue Recognition (Details) $ in Thousands	Dec. 31, 2018USD ($)
Lease Agreements
Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract]
2019	$ (5,166)
2020	(4,398)
2021	(1,495)
2022	(1,192)
2023	(633)
Other Identifiable Assets
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	5,486
2020	4,728
2021	3,376
2022	1,813
2023	$ 1,453

Significant Accounting Polici_6

Significant Accounting Policies - Concentrations of Credit Risk and Reclassification (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Concentrations of Credit Risk
Financing receivable number of days past due for suspending income recognition	90 days
Loan loss and other investment reserves, net of recoveries	$ 5,750,000	$ 0	$ 0
Annualized cash rent | Customer concentration
Concentrations of Credit Risk
Maximum percentage of annualized cash rent for any one tenant not individually disclosed (more than)	5.00%
Annualized cash rent | Customer concentration | 1185 Avenue of the Americas
Concentrations of Credit Risk
Percentage of concentration	14.90%	15.60%	14.80%
Annualized cash rent | Customer concentration | 625 Madison Avenue
Concentrations of Credit Risk
Percentage of concentration	10.90%	10.20%	9.60%
Annualized cash rent | Customer concentration | 919 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	8.60%	8.30%	8.10%
Annualized cash rent | Customer concentration | 750 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	8.40%	8.00%	7.70%
Annualized cash rent | Customer concentration | 810 Seventh Avenue
Concentrations of Credit Risk
Percentage of concentration	8.40%	8.00%	7.30%
Annualized cash rent | Customer concentration | 555 W. 57th Street
Concentrations of Credit Risk
Percentage of concentration	7.50%	6.90%	6.60%
Annualized cash rent | Customer concentration | 125 Park Avenue
Concentrations of Credit Risk
Percentage of concentration	7.30%	6.80%	6.60%
Annualized cash rent | Customer concentration | 1350 Avenue of the Americas
Concentrations of Credit Risk
Percentage of concentration	7.10%	6.80%	6.40%
Annualized cash rent | Customer concentration | 711 Third Avenue
Concentrations of Credit Risk
Percentage of concentration	5.90%	5.10%	5.20%

Properties Held for Sale and _3

Properties Held for Sale and Property Dispositions (Details) $ in Millions	1 Months Ended									3 Months Ended
	Nov. 30, 2018USD ($)a	Jul. 31, 2018USD ($)ft²	Jun. 30, 2018USD ($)ft²	May 31, 2018USD ($)ft²	Oct. 31, 2017USD ($)ft²	Sep. 30, 2017	Jul. 31, 2017USD ($)ft²	Apr. 30, 2017USD ($)ft²	May 31, 2016USD ($)a	Dec. 31, 2018USD ($)ft²	Jun. 30, 2018USD ($)ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²										10,535,316
400 Summit Lake Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | a	40
Sales Price	$ 3
Gain (Loss) on Sale	$ (36.2)
1-6 International Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²		540,000
Sales Price		$ 55
Gain (Loss) on Sale		$ (2.6)
635 Madison Avenue 635
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²			176,530								176,530
Sales Price			$ 153								$ 153
Gain (Loss) on Sale			$ (14.1)
115-117 Stevens Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²				178,000
Sales Price				$ 12
Gain (Loss) on Sale				$ (0.7)
125 Chubb Way
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²					278,000
Sales Price					$ 29.5
Gain (Loss) on Sale					$ (26.1)
16 Court Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²					317,600
Sales Price					$ 171
Gain (Loss) on Sale					$ 64.9
Employee compensation awards accrued										$ 2.5
680-750 Washington Boulevard
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²							325,000
Sales Price							$ 97
Gain (Loss) on Sale							$ (44.2)
520 White Plains Road
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²								180,000
Sales Price								$ 21
Gain (Loss) on Sale								$ (14.6)
102 Greene Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | ft²								9,200
Sales Price								$ 43.5
Gain (Loss) on Sale								$ 4.9
Employee compensation awards accrued											$ 0.9
Joint venture ownership percentage sold						10.00%		90.00%
7 International Drive
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Usable Square Feet (sqft) | a									31
Sales Price									$ 20
Gain (Loss) on Sale									$ (6.9)

Debt and Preferred Equity Inv_3

Debt and Preferred Equity Investments - Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Mortgage Loans on Real Estate [Line Items]
Balance at beginning of period	$ 2,114,041	$ 1,640,412
Redemptions/sales/syndications/amortization	(994,906)	(813,418)
SEC Schedule, 12-29, Real Estate Companies, Investment In Mortgage Loans On Real Estate, Loan Loss Reserve Period Increase (Decrease)	(5,750)	0
Balance at end of period	1,956,119	2,114,041	$ 1,640,412
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of year	0	0	0
Expensed	5,750	0	0
Recoveries	0	0	0
Charge-offs and reclassifications	0	0	0
Balance at end of period	5,750	0	$ 0
Debt Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Originations/Accretion	834,304	1,142,591
Preferred Equity Investments in Mortgage Loans
Mortgage Loans on Real Estate [Line Items]
Originations/Accretion	$ 8,430	$ 144,456

Debt and Preferred Equity Inv_4

Debt and Preferred Equity Investments - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018USD ($)loansegment	Dec. 31, 2017USD ($)segment	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Mortgage Loans on Real Estate [Line Items]
Loan loss reserves	$ 5,750,000	$ 0	$ 0	$ 0
Number of investments marketed for sale | loan	2
Unpaid principal balance	$ 159,900,000
Number of portfolio segments Number | segment	1	1
Financing receivable, recorded in other assets	$ 136,500,000	$ 93,400,000
Financing receivable, recorded investment, nonaccrual status	$ 28,400,000
Weighted average risk rating	1.2
Aggregate weighted average current yield (as a percent)	8.99%
Junior Mortgage Participation Acquired in September 2014 [Member]
Mortgage Loans on Real Estate [Line Items]
Payments to acquire loans receivable		0
Debt Investments Held [Abstract]
Carrying Value		0
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 with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Amount participated out	14,600,000
Mezzanine Loan 2 with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Amount participated out	14,100,000
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	4,129,847,000
Carrying Value	430,099,000	669,968,000
Total fixed rate | Mortgage and Jr Mortgage Loan with an Initial Maturity Date of April 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,160,000,000
Carrying Value	213,185,000	204,005,000
Total fixed rate | Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000,000
Carrying Value	3,500,000	3,500,000
Total fixed rate | Mortgage Loan, August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	147,000,000
Carrying Value	24,932,000	24,913,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of March 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	280,000,000
Carrying Value	36,585,000	34,600,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of September 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,097,000
Carrying Value	12,706,000	12,699,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of April 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	180,000,000
Carrying Value	30,000,000	0
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of November 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000,000
Carrying Value	12,941,000	12,932,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2024
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000,000
Carrying Value	30,000,000	30,000,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	340,000,000
Carrying Value	11,000,000	15,000,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of November 2026
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,712,750,000
Carrying Value	55,250,000	55,250,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2027
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	250,464,000
Total fixed rate | Mezzanine Loan Repaid in June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	26,366,000
Total fixed rate | Junior Mortgage Participation/Mezzanine Loan Repaid in March 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	239,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of March 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	45,025,000
Carrying Value	37,499,000	34,879,000
Total floating rate | Junior Mortgage Participation, April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Carrying Value	14,822,000	14,869,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000,000
Carrying Value	15,333,000	15,381,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000,000
Carrying Value	19,986,000	19,982,000
Total floating rate | Mortgage/Mezzanine Loan 2 with an Initial Maturity Date of August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	265,000,000
Carrying Value	24,961,000	24,830,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of September 2018
Debt Investments Held [Abstract]
Future Funding Obligations	40,530,000
Senior Financing	233,086,000
Carrying Value	84,012,000	71,832,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000,000
Carrying Value	21,990,000	21,939,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of September 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000,000
Carrying Value	14,998,000	14,955,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of October 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	19,999,000	19,940,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of October 2018
Debt Investments Held [Abstract]
Future Funding Obligations	1,027,000
Senior Financing	0
Carrying Value	154,070,000	143,919,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of November 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	350,000,000
Carrying Value	34,886,000	34,737,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	7,243,000
Senior Financing	0
Carrying Value	62,493,000	43,845,000
Total floating rate | Mezzanine Loan 2 with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	559,000
Senior Financing	575,955,000
Carrying Value	79,164,000	75,834,000
Total floating rate | Mezzanine Loan 3 with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	11,204,000
Senior Financing	0
Carrying Value	88,501,000	0
Total floating rate | Mezzanine Loan 4 with an Initial Maturity Date of December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	1,277,000
Senior Financing	322,300,000
Carrying Value	53,402,000	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	14,860,000
Senior Financing	0
Carrying Value	277,694,000	0
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	37,094,000	0
Total floating rate | Mezzanine Loan 3 with an Initial Maturity of January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	7,887,000
Senior Financing	38,167,000
Carrying Value	12,627,000	11,259,000
Total floating rate | Mezzanine Loan, March 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	83,449,000	0
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	38,575,000
Senior Financing	362,908,000
Carrying Value	88,817,000	75,428,000
Total floating rate | Mezzanine Loan 2 with an Initial Maturity Date of April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	33,131,000
Senior Financing	0
Carrying Value	98,804,000	88,989,000
Total floating rate | Mortgage/Jr Mortgage Participation Loan, Maturity Date of August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	35,266,000	35,152,000
Total floating rate | Mezzanine Loan, Maturity of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000,000
Carrying Value	15,665,000	15,635,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,596,000
Carrying Value	7,305,000	34,947,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of October 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	162,553,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	74,755,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	23,609,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of July 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	16,969,000
Total floating rate | Mezzanine Loan with an Initial Maturity Date of November 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	59,723,000
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	37,851,000
Total floating rate | Mortgage/Mezzanine Loan 2 with an Initial Maturity Date of December 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	14,855,000
Total floating rate | Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity Date of July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	12,174,000
Total floating rate | Mezzanine Loan With An Initial Maturity Date of August 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	10,934,000
Total floating rate | Mortgage/Mezzanine Loan Repaid in December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	37,250,000
Total floating rate | Mezzanine Loan Repaid in November 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	15,148,000
Total floating rate | Mezzanine Loan Repaid in September 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	8,550,000
Total floating rate | Mortgage/Mezzanine Loan Repaid in June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	26,927,000
Total floating rate | Mortgage/Mezzanine Loan 2 Repaid in June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	156,293,000
Senior Financing	2,584,037,000
Carrying Value	1,382,837,000	1,299,650,000
Total floating rate | Mezzanine Loan Contributed to Joint Venture in May 2017
Debt Investments Held [Abstract]
Future Funding Obligations	156,293,000
Senior Financing	6,713,884,000
Carrying Value	$ 1,812,936,000	$ 1,969,618,000

Debt and Preferred Equity Inv_5

Debt and Preferred Equity Investments - Preferred Equity Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	8.99%
Preferred Equity, April 2021
Mortgage Loans on Real Estate [Line Items]
Future Funding Obligations	$ 0
Senior Financing	272,000
Carrying Value	$ 143,183	$ 144,423
Preferred Equity Investments
Mortgage Loans on Real Estate [Line Items]
Interest rate (as a percent)	5.80%
Future Funding Obligations	$ 0
Senior Financing	272,000
Carrying Value	$ 143,183	$ 144,423

Investments in Unconsolidated_3

Investments in Unconsolidated Joint Ventures - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended								12 Months Ended
	Jan. 31, 2019USD ($)	May 31, 2018	Dec. 31, 2018USD ($)ft²	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)ft²note	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Purchase price and other fair value adjustment			$ 0	$ 0	$ 0	$ 54,860					$ 54,860	$ 0	$ 0
Approximate Square Feet (unaudited) | ft²			10,535,316								10,535,316
Loans receivable, gross, commercial, acquisition			$ 0				$ 126,716				$ 0	126,716
Total mortgages and other loans payable			615,550				840,809				615,550	840,809
Total joint venture mortgages and other loans payable			607,569				829,648				607,569	829,648
Commercial real estate property, net			4,143,153				5,536,852				4,143,153	5,536,852
Debt and preferred equity investments			1,956,119				2,114,041				1,956,119	2,114,041
Other assets			217,967				245,598				217,967	245,598
Other liabilities			87,077				92,514				87,077	92,514
Company's investments in unconsolidated joint ventures			339,302				130,217				339,302	130,217
Operating expenses											131,212	164,219	166,137
Real estate taxes											130,532	156,967	152,010
Ground rent											19,798	20,941	20,971
Amortization of deferred financing costs											4,532	9,313	7,918
Depreciation and amortization											166,372	205,795	212,514
Total expenses			131,216	128,487	130,334	131,150	164,490	$ 180,142	$ 167,865	$ 169,206	521,187	681,703	669,716
Equity in net income from unconsolidated joint ventures			$ 363	$ (164)	$ 1,252	$ 2,747	3,830	$ 2,927	$ 3,180	$ 4,255	$ 4,198	14,192	14,509
919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Ownership Interest			51.00%								51.00%
Economic Interest (as a percent)			51.00%								51.00%
Approximate Square Feet (unaudited) | ft²			1,454,000								1,454,000
Acquisition Price			$ 1,256,727								$ 1,256,727
Total fixed rate debt			$ 0				500,000				$ 0	500,000
131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Ownership Interest			20.00%								20.00%
Economic Interest (as a percent)			20.00%								20.00%
Approximate Square Feet (unaudited) | ft²			68,342								68,342
Acquisition Price			$ 277,750								$ 277,750
76 11th Avenue
Schedule of Equity Method Investments [Line Items]
Ownership Interest			33.33%								33.33%
Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Total joint venture mortgages and other loans payable			$ 641,000				141,000				$ 641,000	141,000
Deferred financing costs, net			(1,754)				(2,862)				(1,754)	(2,862)
Total joint venture mortgages and other loans payable, net			639,246				138,138				639,246	138,138
Commercial real estate property, net			1,802,698				273,116				1,802,698	273,116
Debt and preferred equity investments			0				141,716				0	141,716
Other assets			479,005				15,735				479,005	15,735
Total assets			2,281,703				430,567				2,281,703	430,567
Mortgages and other loans payable, net			639,246				138,138				639,246	138,138
Other liabilities			608,469				18,908				608,469	18,908
Members' equity			1,033,988				273,521				1,033,988	273,521
Total liabilities and members' equity			2,281,703				430,567				2,281,703	430,567
Company's investments in unconsolidated joint ventures			339,302				130,217				339,302	130,217
Total revenues											147,411	35,204	38,524
Operating expenses											24,977	877	1,238
Real estate taxes											30,462	1,389	1,192
Ground rent											1,851	0	0
Interest expense, net of interest income											32,849	3,769	2,895
Amortization of deferred financing costs											1,108	1,114	1,108
Depreciation and amortization											50,468	8,405	8,404
Total expenses											141,715	15,554	14,837
Net income											5,696	19,650	23,687
Equity in net income from unconsolidated joint ventures											4,198	14,192	$ 14,509
Corporate Joint Venture | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Purchase price and other fair value adjustment											54,900
Total fixed rate debt			500,000				0				500,000	0
Corporate Joint Venture | 131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Total mortgages and other loans payable			141,000				141,000				$ 141,000	141,000
Corporate Joint Venture | 76 11th Avenue
Schedule of Equity Method Investments [Line Items]
Number of mezzanine notes secured | note											2
Participating Financing Due March 2017
Schedule of Equity Method Investments [Line Items]
Loans receivable, gross, commercial, acquisition			0				100,000				$ 0	100,000
Mezzanine Loan Due July 2036
Schedule of Equity Method Investments [Line Items]
Loans receivable, gross, commercial, acquisition			$ 0				$ 26,716				$ 0	$ 26,716
Weighted Average | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Interest rate (as a percent)
Weighted Average | Corporate Joint Venture | 919 Third Avenue
Schedule of Equity Method Investments [Line Items]
Interest rate (as a percent)			5.12%								5.12%
Weighted Average | Corporate Joint Venture | 131-137 Spring Street
Schedule of Equity Method Investments [Line Items]
Interest Rate (as a percent)			1.55%								1.55%
Subsequent Event
Schedule of Equity Method Investments [Line Items]
Proceeds from Sale of Equity Method Investments	$ 15,200
2 Herald Square
Schedule of Equity Method Investments [Line Items]
Leasehold Investment, Tenancy In Common Interest, Ownership Percentage		49.00%

Investments in Unconsolidated_4

Investments in Unconsolidated Joint Ventures - Sale of Joint Venture Interests or Properties (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
2 Herald Square
Schedule of Equity Method Investments [Line Items]
Ownership Interest	49.00%
Gross Asset Valuation	$ 265,000
Gain on Sale	$ 0
Mezzanine Loan
Schedule of Equity Method Investments [Line Items]
Ownership Interest	33.33%
Gross Asset Valuation	$ 15,000
102 Greene Street
Schedule of Equity Method Investments [Line Items]
Ownership Interest	10.00%
Gross Asset Valuation	$ 43,500
Gain on Sale	$ 283
76 11th Avenue
Schedule of Equity Method Investments [Line Items]
Ownership Interest	33.33%
Gross Asset Valuation	$ 138,240

Mortgages and Other Loans Pay_3

Mortgages and Other Loans Payable (Details)	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2018USD ($)debt_instrumentextension_option	Apr. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Mortgage note and other loan payable
Total mortgages and other loans payable		$ 615,550,000		$ 840,809,000
Deferred financing costs, net of amortization		(7,981,000)		(11,161,000)
Total mortgages and other loans payable, net		607,569,000		829,648,000
Collateral already posted, aggregate fair value		$ 1,000,000,000		1,900,000,000
Maximum borrowing capacity			$ 400,000,000
Number of extension options | extension_option		2
Period of extension option	1 year	1 year
Uncommitted Master Repurchase Agreements
Mortgage note and other loan payable
Number of debt instruments | debt_instrument		2
Uncommitted Master Repurchase Agreement, 2
Mortgage note and other loan payable
Maximum borrowing capacity		$ 300,000,000
Debt instrument, term		1 year
Revolving credit facility, net		$ 299,600,000
2017 Master Repurchase Agreement
Mortgage note and other loan payable
Total mortgages and other loans payable		300,000,000		90,809,000
2016 Master Repurchase Agreement
Mortgage note and other loan payable
Total mortgages and other loans payable		65,550,000		0
Maximum borrowing capacity		$ 300,000,000
Debt instrument, term		2 years
Period of extension option		1 year
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
Total fixed rate debt		250,000,000		250,000,000
919 Third Avenue
Mortgage note and other loan payable
Total fixed rate debt		$ 0		$ 500,000,000
Weighted Average | 2017 Master Repurchase Agreement
Mortgage note and other loan payable
Interest Rate (as a percent)		2.34%
Weighted Average | 2016 Master Repurchase Agreement
Mortgage note and other loan payable
Interest Rate (as a percent)		3.40%
Weighted Average | 315 West 33rd Street
Mortgage note and other loan payable
Interest rate (as a percent)		4.24%
Weighted Average | 919 Third Avenue
Mortgage note and other loan payable
Interest rate (as a percent)
LIBOR | Minimum | 2016 Master Repurchase Agreement
Mortgage note and other loan payable
Interest rate (as a percent)		2.25%
LIBOR | Maximum | 2016 Master Repurchase Agreement
Mortgage note and other loan payable
Interest rate (as a percent)		4.00%
SL Green
Mortgage note and other loan payable
Collateral already posted, aggregate fair value		$ 20,000,000

Corporate Indebtedness (Details

Corporate Indebtedness (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2017
Scheduled amortization and principal repayments
2018		$ 0
2019		300,000
2020		0
2021		0
2022		65,550
Thereafter		250,000
Total amortization of debt and principal repayments		615,550
Interest expense
Interest expense before capitalized interest		67,647	$ 124,507	$ 110,393
Interest capitalized		(5,560)	(533)	(1,171)
Interest income		(6)	(5)	(14)
Interest expense, net		62,081	123,969	$ 109,208
Mortgage and Other Loans Payable
Scheduled Amortization
2018		0
2019		0
2020		0
2021		0
2022		0
Thereafter		0
Total amortization of debt		0
Principal
2018		0
2019		300,000
2020		0
2021		0
2022		65,550
Thereafter		250,000
Total principal repayments		615,550
Mortgage and Other Loans Payable | Corporate Joint Venture
Principal
2018		0
2019		28,200
2020		0
2021		0
2022		255,000
Thereafter		0
Total principal repayments		283,200
Line of Credit | Credit Facility 2012
Scheduled amortization and principal repayments
Total amortization of debt and principal repayments					$ 1,200,000
Senior Unsecured Bonds | 4.50% senior unsecured notes maturing in December 2022
Debt disclosures by scheduled maturity date
Interest rate	4.50%
Face amount	$ 100,000
Redemption price, percentage	105.334%
Senior Unsecured Notes
Debt disclosures by scheduled maturity date
Unpaid principal balance		0
Accreted Balance		0	905,116
Deferred financing costs, net		0	(4,049)
Senior notes, net of deferred finance costs		0	901,067
Senior Unsecured Notes | 5.00% senior unsecured notes maturing on August 15, 2018
Debt disclosures by scheduled maturity date
Unpaid principal balance		0
Accreted Balance		$ 0	250,000
Interest rate
Debt instrument, term
Senior Unsecured Notes | 7.75% senior unsecured notes maturing on March 15, 2020
Debt disclosures by scheduled maturity date
Unpaid principal balance		$ 0
Accreted Balance		$ 0	305,163
Interest rate
Debt instrument, term
Senior Unsecured Notes | 4.50% senior unsecured notes maturing on December 01, 2022
Debt disclosures by scheduled maturity date
Unpaid principal balance		$ 0
Accreted Balance		$ 0	100,000
Interest rate
Debt instrument, term
Senior Unsecured Notes | 4.27% senior unsecured notes maturing on December 17, 2025
Debt disclosures by scheduled maturity date
Unpaid principal balance		$ 0
Accreted Balance		$ 0	$ 249,953
Interest rate
Debt instrument, term

Preferred Units (Details)

Preferred Units (Details)	12 Months Ended
	Dec. 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 liability | $	$ 0		$ 0
Partnership Interest | Series A Preferred Units
Class of Stock [Line Items]
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares)	109,161
Dividend rate preferred units (as a percent)	3.50%
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 1,000
Number of preferred units issued (in shares)		109,161
Annual dividends on preferred units (in dollars per share) | $ / shares	$ 35
Partnership Interest | Series B Preferred Units
Class of Stock [Line Items]
Number of preferred units issued (in shares)	0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value of Financial Instruments
Asset Impairment Charges	$ 106,400
Purchase price and other fair value adjustment		$ 0	$ 0	$ 0	$ 54,860	$ 54,860	$ 0	$ 0
Interest rate cap and swap agreements (included in other assets)	0	0				0	167
Debt and preferred equity investments	1,956,119	1,956,119				1,956,119	2,114,041
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0	0				0	0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0	0				0	167
Level 3
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0	0				0	0
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments	1,956,119	1,956,119				1,956,119	2,114,041
Fixed rate debt	250,000	250,000				250,000	1,655,116
Variable rate debt	365,550	365,550				365,550	90,809
Total	615,550	615,550				615,550	1,745,925
Fair Value | Level 3
Fair Value of Financial Instruments
Fixed rate debt	249,919	249,919				249,919	1,715,501
Variable rate debt	374,387	374,387				374,387	92,087
Total	624,306	624,306				624,306	1,807,588
Minimum | Fair Value
Fair Value of Financial Instruments
Mortgage loans on real estate, fair value, low end of range	2,000,000	2,000,000				2,000,000	2,100,000
Maximum | Fair Value
Fair Value of Financial Instruments
Mortgage loans on real estate, fair value, high end of range	$ 2,200,000	$ 2,200,000				$ 2,200,000	$ 2,300,000

Financial Instruments_ Deriva_3

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (loss) from changes in fair value	$ (200)	$ 200	$ 0
Loss from settlement of hedges included in accumulated other comprehensive loss	0	1,300
Amount of Loss Recognized in Other Comprehensive Loss (Effective Portion)	0	0	(13)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	0	359	611
Amount of Gain Recognized into Income (Ineffective Portion)	$ 0	$ 0	$ 3

Rental Income (Details)

Rental Income (Details) $ in Thousands	Dec. 31, 2018USD ($)
Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases
2018	$ 45,500
2019	44,765
2020	47,595
2021	32,693
2022	32,759
Thereafter	250,340
Total minimum lease payments	453,652
Consolidated Properties
Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases
2018	514,204
2019	463,658
2020	412,040
2021	373,056
2022	328,287
Thereafter	1,362,314
Total minimum lease payments	$ 3,453,559

Related Party Transactions (Det

Related Party Transactions (Details) - Affiliate - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 22, 2016
Related Party Transactions
Profit participation received from related party	$ 3.4	$ 3.4	$ 3.3
Alliance Building Services
Related Party Transactions
Payments made for services	9.3	10	8.1
SL Green
Related Party Transactions
Allocation of salary and other operating costs from related party	11.2	12.8	11.5
Insurance expense incurred	$ 4.2	$ 5.4	$ 5.9
Related party payable				$ 23.8
Interest rate				6.00%

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Multi-employer plans
Plan contributions from all employers	$ 8,169	$ 9,898	$ 9,487
Health Plan
Multi-employer plans
Plan contributions from all employers				$ 1,400,000	$ 1,300,000	$ 1,200,000
Contributions by company (less than)	5.00%
Pension Plan
Multi-employer plans
Surcharge	No
Plan contributions from all employers				$ 272,300	$ 257,800	$ 249,500

Benefit Plans - Contributions M

Benefit Plans - Contributions Made to Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Multi-employer plans
Plan contributions	$ 8,169	$ 9,898	$ 9,487
Health Plan
Multi-employer plans
Plan contributions	5,667	6,764	6,366
Other plans
Multi-employer plans
Plan contributions	683	865	902
Pension Plan
Multi-employer plans
Plan contributions	$ 1,819	$ 2,269	$ 2,219

Commitments and Contingencies_2

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)extension_option
Other Commitments [Line Items]
Minimum initial term of noncancellable operating leases (in years)	1 year
Non-cancellable operating leases
2019	$ 19,736
2020	19,736
2021	19,886
2022	17,730
2023	15,424
Thereafter	237,011
Total minimum lease payments	329,523
Future minimum sublease rentals under non-cancellable subleases	$ 1,000,000
711 Third Avenue | Through July 2016
Other Commitments [Line Items]
Number of renewal options available | extension_option	5
Term of first renewal option (in years)	10 years
Required annual ground lease payments	$ 5,250
711 Third Avenue | After July 2016
Other Commitments [Line Items]
Required annual ground lease payments	$ 5,500
Percentage of the fee not owned by the entity	50.00%
711 Third Avenue | After July 2021
Other Commitments [Line Items]
Required annual ground lease payments	$ 5,500
Land as percentage of the fair value of the land	7.75%
461 Fifth Avenue
Other Commitments [Line Items]
Number of renewal options available | extension_option	2
Required annual ground lease payments	$ 2,100
Term of second renewal option (in years)	21 years
Term of third renewal option (in years)	15 years
625 Madison Avenue
Other Commitments [Line Items]
Number of renewal options available | extension_option	2
Required annual ground lease payments	$ 4,600
Term of second renewal option (in years)	32 years
1185 Avenue of the Americas
Other Commitments [Line Items]
Required annual ground lease payments	$ 6,900
1055 Washington Boulevard
Other Commitments [Line Items]
Required annual ground lease payments	600
Ticonderoga Insurance Company
Other Commitments [Line Items]
Secured advances	$ 27,500

Quarterly Financial Data of t_3

Quarterly Financial Data of the Company (unaudited) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 200,239	$ 198,587	$ 211,048	$ 206,229	$ 241,463	$ 241,908	$ 251,812	$ 232,355	$ 816,103	$ 967,538	$ 975,416
Total expenses	131,216	128,487	130,334	131,150	164,490	180,142	167,865	169,206	521,187	681,703	669,716
Equity in net income from unconsolidated joint ventures	363	(164)	1,252	2,747	3,830	2,927	3,180	4,255	4,198	14,192	14,509
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	(1)	6,345	270	(633)	387	282	0	3	5,981	672	0
(Loss) gain on sale of real estate, net	(36,459)	(2,773)	(14,863)	0	64,779	114	4,933	0	(54,095)	69,826	(6,909)
Purchase price and other fair value adjustment	0	0	0	54,860					54,860	0	0
Depreciable real estate reserves and impairment	(106,376)	0	0	0	(86,364)	(379)	(29,063)	(56,265)	(106,376)	(172,071)	0
Net income	(73,450)	73,508	67,373	132,053	59,605	64,710	62,997	11,142	199,484	198,454	313,300
Net (income) loss attributable to noncontrolling interests in other partnerships	(2)	(212)	(212)	(292)	(2,147)	1,467	18,134	(14)	(718)	17,440	(4,424)
Preferred units dividend	(956)	(955)	(955)	(955)	(956)	(955)	(955)	(953)	(3,821)	(3,819)	(3,821)
Net income attributable to ROP common unitholder	$ (74,408)	$ 72,341	$ 66,206	$ 130,806	$ 56,502	$ 65,222	$ 80,176	$ 10,175	$ 194,945	$ 212,075	$ 305,055

Segment Information (Details)

Segment Information (Details) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment information
Number of reportable segments | segment										2
Total revenues		$ 200,239	$ 198,587	$ 211,048	$ 206,229	$ 241,463	$ 241,908	$ 251,812	$ 232,355	$ 816,103	$ 967,538	$ 975,416
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, depreciable real estate reserves, and loss on early extinguishment of debt.										199,484	198,454	313,300
Total assets	[1]	7,009,297				8,541,508				7,009,297	8,541,508
Operating Segments | Real Estate Segment
Segment information
Total revenues										625,695	773,561	761,314
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, depreciable real estate reserves, and loss on early extinguishment of debt.										74,460	27,985	108,304
Total assets		4,917,674				6,182,300				4,917,674	6,182,300
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues										190,408	193,977	214,102
Income before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain (loss) on sale of real estate, depreciable real estate reserves, and loss on early extinguishment of debt.										125,024	170,469	$ 204,996
Total assets		$ 2,091,623				$ 2,359,208				$ 2,091,623	$ 2,359,208
[1]	The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs: $268.6 million and $297.3 million of land, $1.3 billion and $1.4 billion of building and improvements, $319.1 million and $318.4 million of accumulated depreciation, $143.9 million and $160.5 million of other assets included in other line items, $495.0 million and $494.0 million of real estate debt, net, $2.1 million and $2.1 million of accrued interest payable, and $48.8 million and $61.4 million of other liabilities included in other line items as of December 31, 2017 and December 31, 2016, respectively.

Schedule II_Valuation and Qua_2

Schedule II—Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tenant and other receivables—allowance
Changes in valuation allowance
Balance at Beginning of Year	$ 7,237	$ 4,879	$ 5,593
Additions Charged Against Operations/Recovery	3,063	3,657	3,604
Uncollectible Accounts Written-off	(3,505)	(1,299)	(4,318)
Balance at End of Year	6,795	7,237	4,879
Deferred rent receivable—allowance
Changes in valuation allowance
Balance at Beginning of Year	11,189	17,798	14,788
Additions Charged Against Operations/Recovery	469	2,084	3,955
Uncollectible Accounts Written-off	(2,123)	(8,693)	(945)
Balance at End of Year	$ 9,535	$ 11,189	$ 17,798

Schedule III_Real Estate And _2

Schedule III—Real Estate And Accumulated Depreciation - Real Estate And Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Real Estate And Accumulated Depreciation
Encumbrances	$ 315,550
Initial Cost
Land	1,232,012
Building & Improvements	3,555,428
Cost Capitalized Subsequent To Acquisition
Land	(17,477)
Building & Improvements	689,407
Gross Amount at Which Carried at Close of Period
Land	1,214,535
Building & Improvements	4,244,835
Total	5,459,370	$ 7,029,455	$ 7,508,870	$ 7,428,243
Accumulated Depreciation	1,316,217	$ 1,492,603	$ 1,437,222	$ 1,267,598
810 Seventh Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	114,077
Building & Improvements	476,386
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	74,433
Gross Amount at Which Carried at Close of Period
Land	114,077
Building & Improvements	550,819
Total	664,896
Accumulated Depreciation	176,354
461 Fifth Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building & Improvements	62,695
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	25,581
Gross Amount at Which Carried at Close of Period
Land	0
Building & Improvements	88,276
Total	88,276
Accumulated Depreciation	29,680
750 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	51,093
Building & Improvements	205,972
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	45,551
Gross Amount at Which Carried at Close of Period
Land	51,093
Building & Improvements	251,523
Total	302,616
Accumulated Depreciation	101,854
555 W. 57th Street
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	18,846
Building & Improvements	78,704
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	62,242
Gross Amount at Which Carried at Close of Period
Land	18,846
Building & Improvements	140,946
Total	159,792
Accumulated Depreciation	69,817
1185 Avenue of the Americas
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building & Improvements	728,213
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	62,893
Gross Amount at Which Carried at Close of Period
Land	0
Building & Improvements	791,106
Total	791,106
Accumulated Depreciation	265,896
1350 Avenue of the Americas
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	91,038
Building & Improvements	380,744
Cost Capitalized Subsequent To Acquisition
Land	(97)
Building & Improvements	50,773
Gross Amount at Which Carried at Close of Period
Land	90,941
Building & Improvements	431,517
Total	522,458
Accumulated Depreciation	136,853
100 Summit Lake Drive
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	10,526
Building & Improvements	43,109
Cost Capitalized Subsequent To Acquisition
Land	(3,337)
Building & Improvements	(94)
Gross Amount at Which Carried at Close of Period
Land	7,189
Building & Improvements	43,015
Total	50,204
Accumulated Depreciation	18,936
200 Summit Lake Drive
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	11,183
Building & Improvements	47,906
Cost Capitalized Subsequent To Acquisition
Land	(5,321)
Building & Improvements	(9,102)
Gross Amount at Which Carried at Close of Period
Land	5,862
Building & Improvements	38,804
Total	44,666
Accumulated Depreciation	21,203
500 Summit Lake Drive
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	9,777
Building & Improvements	39,048
Cost Capitalized Subsequent To Acquisition
Land	(3,601)
Building & Improvements	(7,875)
Gross Amount at Which Carried at Close of Period
Land	6,176
Building & Improvements	31,173
Total	37,349
Accumulated Depreciation	14,523
360 Hamilton Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	29,497
Building & Improvements	118,250
Cost Capitalized Subsequent To Acquisition
Land	(2,625)
Building & Improvements	8,005
Gross Amount at Which Carried at Close of Period
Land	26,872
Building & Improvements	126,255
Total	153,127
Accumulated Depreciation	43,901
1010 Washington Boulevard
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	7,747
Building & Improvements	30,423
Cost Capitalized Subsequent To Acquisition
Land	(1,259)
Building & Improvements	2,928
Gross Amount at Which Carried at Close of Period
Land	6,488
Building & Improvements	33,351
Total	39,839
Accumulated Depreciation	12,489
1055 Washington Boulevard
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	13,516
Building & Improvements	53,228
Cost Capitalized Subsequent To Acquisition
Land	(5,130)
Building & Improvements	(9,986)
Gross Amount at Which Carried at Close of Period
Land	8,386
Building & Improvements	43,242
Total	51,628
Accumulated Depreciation	20,382
609 Fifth Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	36,677
Building & Improvements	145,954
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	49,527
Gross Amount at Which Carried at Close of Period
Land	36,677
Building & Improvements	195,481
Total	232,158
Accumulated Depreciation	43,777
110 East 42nd Street
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	34,000
Building & Improvements	46,411
Cost Capitalized Subsequent To Acquisition
Land	(138)
Building & Improvements	28,673
Gross Amount at Which Carried at Close of Period
Land	33,862
Building & Improvements	75,084
Total	108,946
Accumulated Depreciation	16,960
304 Park Avenue South
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	54,189
Building & Improvements	75,619
Cost Capitalized Subsequent To Acquisition
Land	300
Building & Improvements	15,024
Gross Amount at Which Carried at Close of Period
Land	54,489
Building & Improvements	90,643
Total	145,132
Accumulated Depreciation	19,315
635 Sixth Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	24,180
Building & Improvements	37,158
Cost Capitalized Subsequent To Acquisition
Land	163
Building & Improvements	51,103
Gross Amount at Which Carried at Close of Period
Land	24,343
Building & Improvements	88,261
Total	112,604
Accumulated Depreciation	10,931
641 Sixth Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	45,668
Building & Improvements	67,316
Cost Capitalized Subsequent To Acquisition
Land	308
Building & Improvements	9,760
Gross Amount at Which Carried at Close of Period
Land	45,976
Building & Improvements	77,076
Total	123,052
Accumulated Depreciation	15,891
919 Third Avenue (2)
Real Estate And Accumulated Depreciation
Encumbrances	250,000
Initial Cost
Land	195,834
Building & Improvements	164,429
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	15,133
Gross Amount at Which Carried at Close of Period
Land	195,834
Building & Improvements	179,562
Total	375,396
Accumulated Depreciation	25,397
Williamsburg
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,677
Building & Improvements	14,708
Cost Capitalized Subsequent To Acquisition
Land	2,523
Building & Improvements	(4,550)
Gross Amount at Which Carried at Close of Period
Land	6,200
Building & Improvements	10,158
Total	16,358
Accumulated Depreciation	2,127
115 Spring Street
Real Estate And Accumulated Depreciation
Encumbrances	65,550
Initial Cost
Land	11,078
Building & Improvements	44,799
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	1,850
Gross Amount at Which Carried at Close of Period
Land	11,078
Building & Improvements	46,649
Total	57,727
Accumulated Depreciation	5,248
125 Park Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	120,900
Building & Improvements	189,714
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	80,884
Gross Amount at Which Carried at Close of Period
Land	120,900
Building & Improvements	270,598
Total	391,498
Accumulated Depreciation	77,542
625 Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building & Improvements	246,673
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	44,646
Gross Amount at Which Carried at Close of Period
Land	0
Building & Improvements	291,319
Total	291,319
Accumulated Depreciation	118,380
711 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	19,844
Building & Improvements	42,499
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	73,270
Gross Amount at Which Carried at Close of Period
Land	19,844
Building & Improvements	115,769
Total	135,613
Accumulated Depreciation	45,066
752 Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	282,415
Building & Improvements	0
Cost Capitalized Subsequent To Acquisition
Land	1,871
Building & Improvements	1,124
Gross Amount at Which Carried at Close of Period
Land	284,286
Building & Improvements	1,124
Total	285,410
Accumulated Depreciation	12
110 Greene Street
Real Estate And Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	45,120
Building & Improvements	215,470
Cost Capitalized Subsequent To Acquisition
Land	0
Building & Improvements	12,923
Gross Amount at Which Carried at Close of Period
Land	45,120
Building & Improvements	228,393
Total	273,513
Accumulated Depreciation	$ 23,683
Interest in property (as a percent)	90.00%
Other
Real Estate And Accumulated Depreciation
Encumbrances	$ 0
Initial Cost
Land	1,130
Building & Improvements	0
Cost Capitalized Subsequent To Acquisition
Land	(1,134)
Building & Improvements	4,691
Gross Amount at Which Carried at Close of Period
Land	(4)
Building & Improvements	4,691
Total	4,687
Accumulated Depreciation	$ 0

Schedule III_Real Estate And _3

Schedule III—Real Estate And Accumulated Depreciation - Changes in Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in real estate
Balance at beginning of year	$ 7,029,455	$ 7,508,870	$ 7,428,243
Acquisitions	0	0	0
Improvements	133,946	121,959	123,173
Retirements/disposals	(1,704,031)	(601,374)	(42,546)
Balance at end of year	5,459,370	7,029,455	7,508,870
Aggregate cost of land, buildings and improvements, before depreciation, for Federal income tax purposes	4,200,000
Changes in accumulated depreciation, exclusive of amounts relating to equipment, autos, and furniture and fixtures
Balance at beginning of year	1,492,603	1,437,222	1,267,598
Depreciation for year	146,216	178,801	183,873
Retirements/disposals	(322,602)	(123,420)	(14,249)
Balance at end of year	$ 1,316,217	$ 1,492,603	$ 1,437,222