Diversified Healthcare Trust (DHC) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 05, 2018
Document and Entity Information
Entity Registrant Name	SENIOR HOUSING PROPERTIES TRUST
Entity Central Index Key	1,075,415
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		237,730,650
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Emerging Growth Company	false
Entity Smaller Reporting Company	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Real estate properties:
Land	$ 851,084	$ 824,879
Buildings and improvements	7,166,130	6,999,884
Total real estate properties, gross	8,017,214	7,824,763
Accumulated depreciation	(1,607,602)	(1,454,477)
Total real estate properties, net	6,409,612	6,370,286
Cash and cash equivalents	47,657	31,238
Restricted cash	108,335	16,083
Acquired real estate leases and other intangible assets, net	450,219	472,265
Other assets, net	437,621	404,147
Total assets	7,453,444	7,294,019
LIABILITIES AND EQUITY
Unsecured revolving credit facility	195,000	596,000
Unsecured term loans, net	548,080	547,460
Senior unsecured notes, net	2,215,900	1,725,662
Secured debt and capital leases, net	745,269	805,404
Accrued interest	34,727	17,987
Assumed real estate lease obligations, net	88,692	96,018
Other liabilities	231,296	228,300
Total liabilities	4,058,964	4,016,831
Commitments and contingencies
Equity attributable to common shareholders:
Common shares of beneficial interest, $.01 par value: 300,000,000 shares authorized, 237,730,900 and 237,630,409 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	2,377	2,376
Additional paid in capital	4,610,885	4,609,316
Cumulative net income	2,259,338	1,766,495
Cumulative other comprehensive income	(108)	87,231
Cumulative distributions	(3,638,499)	(3,360,468)
Total equity attributable to common shareholders	3,233,993	3,104,950
Noncontrolling interest:
Total equity attributable to noncontrolling interest	160,487	172,238
Total equity	3,394,480	3,277,188
Total liabilities and equity	$ 7,453,444	$ 7,294,019

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized (in shares)	300,000,000	300,000,000
Common shares of beneficial interest, shares issued (in shares)	237,730,900	237,630,409
Common shares of beneficial interest, shares outstanding (in shares)	237,730,900	237,630,409

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Total revenues	$ 278,969	$ 266,673	$ 831,942	$ 796,185
Expenses:
Property operating expenses	115,987	104,689	334,141	308,650
Depreciation and amortization	71,661	66,619	214,300	209,463
General and administrative	31,032	19,883	85,228	57,880
Acquisition and certain other transaction related costs	51	19	138	148
Impairment of assets	4,525	0	5,073	5,082
Total expenses	223,256	191,210	638,880	581,223
Gain on sale of properties	0	0	261,916	0
Dividend income	660	659	1,978	1,978
Unrealized gains and losses on equity securities, net	35,137	0	85,643	0
Interest and other income	248	128	362	323
Interest expense	(45,416)	(40,105)	(133,781)	(124,394)
Gain (loss) on early extinguishment of debt	108	(274)	(22)	(7,627)
Income from continuing operations before income tax expense and equity in earnings of an investee	46,450	35,871	409,158	85,242
Income tax expense	(79)	(109)	(444)	(300)
Equity in earnings of an investee	831	31	882	533
Net income (loss)	47,202	35,793	409,596	85,475
Net income attributable to noncontrolling interest	(1,397)	(1,379)	(4,181)	(2,865)
Net income (loss) attributable to common shareholders	45,805	34,414	405,415	82,610
Other comprehensive income:
Unrealized gain on investments in available for sale securities	0	7,333	0	26,383
Amounts reclassified from cumulative other comprehensive income to net income	0	0	0	5,082
Equity in unrealized gain of an investee	173	116	90	296
Other comprehensive income	173	7,449	90	31,761
Comprehensive income	47,375	43,242	409,686	117,236
Comprehensive income attributable to noncontrolling interest	(1,397)	(1,379)	(4,181)	(2,865)
Comprehensive income attributable to common shareholders	$ 45,978	$ 41,863	$ 405,505	$ 114,371
Weighted average common shares outstanding (basic) (in shares)	237,511	237,421	237,492	237,404
Weighted average common shares outstanding (diluted) (in shares)	237,562	237,460	237,526	237,445
Per common share amounts (basic and diluted):
Net income attributable to common shareholders (in dollars per share)	$ 0.19	$ 0.14	$ 1.71	$ 0.35
Rental income
Revenues:
Total revenues	$ 173,648	$ 168,348	$ 521,961	$ 501,437
Residents fees and services
Revenues:
Total revenues	$ 105,321	$ 98,325	$ 309,981	$ 294,748

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 409,596	$ 85,475
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	214,300	209,463
Amortization of debt issuance costs and debt discounts and premiums	4,579	4,050
Straight line rental income	(8,507)	(10,485)
Amortization of acquired real estate leases and other intangible assets	(4,290)	(3,963)
Loss on early extinguishment of debt	22	7,627
Impairment of assets	5,073	5,082
Gain on sale of properties	(261,916)	0
Unrealized gains and losses on equity securities, net	(85,643)	0
Other non-cash adjustments	(2,828)	(2,829)
Equity in earnings of an investee	(882)	(533)
Change in assets and liabilities:
Other assets	(5,243)	(390)
Accrued interest	16,740	13,714
Other liabilities	5,021	27,438
Net cash provided by operating activities	286,022	334,649
Cash flows from investing activities:
Real estate acquisitions and deposits	(129,493)	(34,227)
Real estate improvements	(65,953)	(89,710)
Proceeds from sale of properties	332,389	0
Net cash provided by (used in) investing activities	136,943	(123,937)
Cash flows from financing activities:
Proceeds from issuance of senior unsecured notes, net	491,560	0
Proceeds from borrowings on revolving credit facility	617,000	572,000
Repayments of borrowings on revolving credit facility	(1,018,000)	(428,000)
Repayment of other debt	(106,038)	(303,964)
Loss on early extinguishment of debt settled in cash	(150)	(5,485)
Payment of debt issuance costs	(4,296)	(6,836)
Repurchase of common shares	(407)	(341)
Proceeds from noncontrolling interest, net	0	255,813
Distributions to noncontrolling interest	(15,932)	(8,587)
Distributions to shareholders	(278,031)	(277,932)
Net cash used in financing activities	(314,294)	(203,332)
Increase in cash and cash equivalents and restricted cash	108,671	7,380
Cash and cash equivalents and restricted cash at beginning of period	47,321	35,578
Cash and cash equivalents and restricted cash at end of period	155,992	42,958
Supplemental cash flows information:
Interest paid	112,462	106,629
Income taxes paid	439	441
Non-cash investing activities:
Acquisitions funded by assumed debt	(44,386)	0
Non-cash financing activities:
Assumption of mortgage notes payable	$ 44,386	$ 0

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 47,657	$ 31,238	$ 28,870
Restricted cash	108,335		14,088
Total cash and cash equivalents and restricted cash shown in the statements of cash flows	$ 155,992	$ 47,321	$ 42,958	$ 35,578

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of Senior Housing Properties Trust and its subsidiaries, or we, us, or our, are unaudited. Certain information and disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes contained in our Annual Report on Form 10-K for the year ended December 31, 2017 , or our Annual Report. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair statement of results for the interim period have been included. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect reported amounts. Actual results could differ from those estimates. Significant estimates in our condensed consolidated financial statements include purchase price allocations, useful lives of fixed assets and impairment of real estate and intangible assets. We have made reclassifications to the financial statements of prior periods to conform to the current period presentation. These reclassifications had no effect on net income or equity. In March 2017, we entered a joint venture with a sovereign investor for one of our properties ( two buildings) leased to medical providers, medical related business, clinics and biotech laboratory tenants, or MOBs, located in Boston, Massachusetts. We have determined that this joint venture is a variable interest entity, or VIE, as defined under the Consolidation Topic of the Financial Accounting Standards Board, or FASB, Accounting Standards Codification. We concluded that we must consolidate this VIE because we have the power to direct the activities that most significantly impact the VIE’s economic performance and we have the obligation to absorb losses of, and the right to receive benefits from, the VIE that could be significant to the VIE, and therefore are the primary beneficiary of the VIE. The assets of this VIE were $1,070,402 and $1,102,986 as of September 30, 2018 and December 31, 2017 , respectively, and consist primarily of the net real estate owned by the joint venture. The liabilities of this VIE were $714,635 and $720,678 as of September 30, 2018 and December 31, 2017 , respectively, and consist primarily of the debt securing the property. The sovereign investor's interest in this consolidated entity is reflected as noncontrolling interest in our condensed consolidated financial statements. See Note 6 for further information about this joint venture.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements On January 1, 2018, we adopted FASB Accounting Standards Update, or ASU, No. 2014-09 (and related clarifying guidance issued by the FASB), Revenue From Contracts With Customers, which outlines a comprehensive model for entities to use in accounting for revenue arising from contracts with customers. ASU No. 2014-09 states that “an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.” While ASU No. 2014-09 specifically references contracts with customers, it may apply to certain other transactions such as the sale of real estate or equipment. A substantial portion of our total revenues, including residents fees and services which relate to contracts with residents for housing services at properties leased to our taxable REIT subsidiaries, or TRSs, consists of rental income from leasing arrangements, which is specifically excluded from ASU No. 2014-09. Our contracts with residents that are within the scope of ASU No. 2014-09 are generally short term in nature. We have adopted ASU No. 2014-09 using the modified retrospective approach. The adoption of ASU No. 2014-09 did not have a material impact on the amount or timing of our revenue recognition in our condensed consolidated financial statements. On January 1, 2018, we adopted FASB ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which changes how entities measure certain equity investments and present changes in the fair value of financial liabilities measured under the fair value option that are attributable to their own credit. The implementation of ASU No. 2016-01 resulted in the reclassification of historical changes in the fair value of our available for sale equity securities of $86,572 from cumulative other comprehensive income to cumulative net income. We also reclassified $841 from cumulative other comprehensive income to cumulative net income for our share of cumulative other comprehensive income of our equity method investee. Effective January 1, 2018, changes in the fair value of our equity securities are recorded through earnings in accordance with ASU No. 2016-01. On January 1, 2018, we adopted FASB ASU No. 2016-18, Restricted Cash , which requires companies to show the changes in the total of cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. ASU No. 2016-18 also requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. As a result, amounts included in restricted cash in our condensed consolidated balance sheets are presented with cash and cash equivalents in our condensed consolidated statements of cash flows to the related captions in the condensed consolidated balance sheets. Restricted cash totaled $108,335 and $14,088 as of September 30, 2018 and 2017 , respectively. The implementation of ASU No. 2016-18 resulted in a $10,259 increase to net cash provided by operating activities for the nine months ended September 30, 2017 . The adoption of ASU No. 2016-18 did not change our balance sheet presentation. In February 2016, the FASB issued ASU No. 2016-02, Leases , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). ASU No. 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease. A lessee is also required to record a right of use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales type leases, direct financing leases and operating leases. ASU No. 2016-02 is effective for reporting periods beginning after December 15, 2018, with early adoption permitted. We are currently assessing the potential impact the adoption of ASU No. 2016-02 will have in our condensed consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) : Measurement of Credit Losses on Financial Instruments , which requires that entities use a new forward looking “expected loss” model that generally will result in the earlier recognition of allowance for credit losses. The measurement of expected credit losses is based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU No. 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2016-13 will have in our condensed consolidated financial statements. We currently expect to adopt the standard using the modified retrospective approach. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees, with certain exceptions. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2018-07 will have in our condensed consolidated financial statements.

Real Estate Properties

Real Estate Properties	9 Months Ended
	Sep. 30, 2018
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties At September 30, 2018 , we owned 443 properties ( 469 buildings) located in 42 states and Washington, D.C. Acquisitions: We have accounted for our 2018 acquisitions as acquisitions of assets unless otherwise noted. We funded our 2018 acquisitions using cash on hand and borrowings under our revolving credit facility, unless otherwise noted. MOBs: In January 2018, we acquired three MOBs ( three buildings) located in Kansas, Missouri and California with a total of approximately 400,000 square feet for an aggregate purchase price of approximately $91,698 , including closing costs of $544 . In March 2018, we acquired one MOB ( one building) located in Virginia with approximately 135,000 square feet for a purchase price of approximately $23,275 , including our assumption of a $11,050 mortgage note and closing costs of $525 . The table below represents the purchase price allocations (including net closing adjustments) of the MOB acquisitions that closed during the nine months ended September 30, 2018 , as described above: Date Location Number of Properties Number of Buildings Square Feet (000’s) Cash Paid Plus Assumed Debt (1) Land Building and Improvements Acquired Real Estate Leases (2) Assumed Debt January 2018 3 States 3 3 400 $ 91,698 $ 16,873 $ 54,605 $ 20,220 $ — March 2018 Virginia 1 1 135 23,275 2,863 11,105 9,307 11,050 4 4 535 $ 114,973 $ 19,736 $ 65,710 $ 29,527 $ 11,050 (1) Cash paid plus assumed debt, if any, includes closing costs. (2) The weighted average amortization period for acquired real estate leases as of the acquisition dates was 5.8 years. Senior Living Community Acquisitions: In November 2017, we entered a transaction agreement with Five Star Senior Living Inc., or Five Star, pursuant to which we agreed to acquire six senior living communities from Five Star. In December 2017, we acquired two of these senior living communities located in Alabama and Indiana with a combined 229 living units for $39,457 , including closing costs of $307 . In January 2018, we acquired one of these senior living communities located in Tennessee with 88 living units for $19,868 , including closing costs of $201 . In February 2018, we acquired one of these senior living communities located in Arizona with 127 living units for $22,622 , including our assumption of approximately $16,748 of mortgage debt principal and closing costs of $372 . In June 2018, we acquired the remaining two of these senior living communities located in Tennessee with a combined 151 living units for $23,860 , including our assumption of approximately $16,588 of mortgage debt principal and closing costs of $560 . In connection with our acquisitions of these senior living communities, we entered management and pooling agreements with Five Star for Five Star to manage these senior living communities for us. The table below represents the purchase price allocations (including net closing adjustments) of the senior living community acquisitions that closed during the nine months ended September 30, 2018 , as described above: Date Location Leased/Managed Number of Properties Units Cash Paid Plus Assumed Debt (1) Land Building and Improvements FF&E Acquired Real Estate Intangible Assets Assumed Debt Premium on Assumed Debt January 2018 Tennessee Managed 1 88 $ 19,868 $ 580 $ 14,884 $ 1,209 $ 3,195 $ — $ — February 2018 Arizona Managed 1 127 22,622 2,017 17,123 390 4,451 16,748 (1,359 ) June 2018 Tennessee Managed 2 151 23,860 965 17,910 1,628 3,843 16,588 (486 ) 4 366 $ 66,350 $ 3,562 $ 49,917 $ 3,227 $ 11,489 $ 33,336 $ (1,845 ) (1) Cash paid plus assumed debt, if any, includes closing costs. Impairment: We periodically evaluate our assets for impairment. Impairment indicators may include declining tenant or resident occupancy, weak or declining profitability from the property, decreasing tenant cash flows or liquidity, our decision to dispose of an asset before the end of its estimated useful life, and legislative, market or industry changes that could permanently reduce the value of an asset. If indicators of impairment are present, we evaluate the carrying value of the affected asset by comparing it to the expected future undiscounted net cash flows to be generated from that asset. If the sum of these expected future net cash flows is less than the carrying value, we reduce the net carrying value of the asset to its estimated fair value. During the three and nine months ended September 30, 2018, we recorded impairment of assets charges of $4,525 and $5,073 , respectively, to write off unamortized assets related to lease defaults at two of our senior living communities located in California and Colorado that were leased to third party private operators. In June 2018, we reached an agreement with the tenant leasing the senior living community in California and its guarantor to settle past due amounts, terminate the lease and transfer operations, and, in connection with this agreement, we received $2,150 of settlement proceeds. We reached an agreement with the tenant leasing the senior living community in Colorado to terminate the lease and transfer operations in November 2018. We entered management agreements with Five Star to operate these communities for our account under TRS structures. We did not record any impairment charges for our real estate properties during the three and nine months ended September 30, 2017. See Note 5 for further information regarding other than temporary impairment losses recorded in 2017 relating to our investments in equity securities. Dispositions: In March 2018, we sold two senior living communities that were leased to Sunrise Senior Living LLC, or Sunrise, for an aggregate sales price of $217,000 , excluding closing costs, resulting in a gain of $181,154 . In May 2018, we sold one senior living community leased to Sunrise for a sales price of $96,000 , excluding closing costs, resulting in a gain of $78,856 . We recognized rental income of $0 and $3,505 during the three and nine months ended September 30, 2018 , respectively, related to these three senior living communities. We currently have $94,348 of proceeds from the sale of the senior living community in May 2018 that are being held in trust and were intended to fund future acquisitions. These proceeds from the sale are classified as restricted cash in our condensed consolidated balance sheets and will be released to us in November 2018. In June 2018, we sold one skilled nursing facility, or SNF, a type of senior living community, that was leased to Five Star and one senior living community that was leased to a private operator, where the tenant exercised its purchase option, for a combined sales price of approximately $21,865 , excluding closing costs, resulting in a net gain of $1,906 . Pursuant to the terms of our lease with Five Star, our annual rental income decreased by $650 from the sale of the SNF that was previously leased to Five Star. We recognized rental income of $0 and $664 during the three and nine months ended September 30, 2018 , respectively, related to the senior living community that was leased to a private operator.

Indebtedness

Indebtedness	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Our principal debt obligations at September 30, 2018 were: (1) outstanding borrowings under our $1,000,000 unsecured revolving credit facility; (2) seven public issuances of senior unsecured notes, including: (a) $400,000 principal amount at an annual interest rate of 3.25% due 2019, (b) $200,000 principal amount at an annual interest rate of 6.75% due 2020, (c) $300,000 principal amount at an annual interest rate of 6.75% due 2021, (d) $250,000 principal amount at an annual interest rate of 4.75% due 2024, (e) $500,000 principal amount at an annual interest rate of 4.75% due 2028, (f) $350,000 principal amount at an annual interest rate of 5.625% due 2042 and (g) $250,000 principal amount at an annual interest rate of 6.25% due 2046; (3) our $350,000 principal amount unsecured term loan due 2020; (4) our $200,000 principal amount unsecured term loan due 2022; and (5) $735,605 aggregate principal amount of mortgages (excluding premiums, discounts and net debt issuance costs) secured by 13 of our properties ( 14 buildings) with maturity dates between 2019 and 2043. The 13 mortgaged properties ( 14 buildings) had a carrying value (before accumulated depreciation) of $1,033,303 at September 30, 2018 . We also had two properties subject to capital leases with lease obligations totaling $10,053 at September 30, 2018 ; these two properties had a carrying value (before accumulated depreciation) of $36,257 at September 30, 2018 , and the capital leases expire in 2026. In February 2018, we issued $500,000 of 4.75% senior unsecured notes due 2028, raising net proceeds of approximately $487,264 after underwriting discounts and expenses. We used the net proceeds of this offering to reduce amounts outstanding under our revolving credit facility. In January 2018, we prepaid, at par plus accrued interest, a mortgage note secured by one of our properties with an outstanding principal balance of approximately $4,338 , a maturity date in September 2043 and an annual interest rate of 4.4% . In July 2018, we prepaid, at par plus accrued interest, mortgage notes secured by 12 of our properties with an aggregate outstanding principal balance of approximately $90,602 , maturity dates in October 2018 and a weighted average annual interest rate of 5.0% . In September 2018, we prepaid, at par plus accrued interest, a mortgage note secured by one of our properties with an outstanding principal balance of approximately $6,325 , a maturity date in January 2019 and an annual interest rate of 4.7% . We have a $1,000,000 revolving credit facility that is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is January 15, 2022, and, subject to the payment of an extension fee and meeting other conditions, we have the option to extend the maturity date of the facility for an additional year. Our revolving credit facility provides that we can borrow, repay and re-borrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. Our revolving credit facility requires annual interest to be paid on borrowings at the rate of LIBOR plus a premium of 120 basis points, plus a facility fee of 25 basis points per annum on the total amount of lending commitments under the facility. The interest rate premium and facility fee are each subject to adjustment based upon changes to our credit ratings. As of September 30, 2018 , the annual interest rate payable on borrowings under our revolving credit facility was 3.4% . The weighted average annual interest rates for borrowings under our revolving credit facility were 3.2% and 2.5% for the three months ended September 30, 2018 and 2017 , respectively, and 2.9% and 2.3% for the nine months ended September 30, 2018 and 2017 , respectively. As of September 30, 2018 , we had $195,000 outstanding and $805,000 available for borrowing, and as of November 5, 2018 , we had $165,000 outstanding and $835,000 available for borrowing under our revolving credit facility. We incurred interest expense and other associated costs related to our revolving credit facility of $2,291 and $3,929 for the three months ended September 30, 2018 and 2017 , respectively, and $7,872 and $9,888 for the nine months ended September 30, 2018 and 2017 , respectively. The facility also includes a feature pursuant to which in certain circumstances maximum borrowings under the facility may be increased to up to $2,000,000 . Our $350,000 term loan matures in January 2020, and is prepayable without penalty at any time. This term loan requires annual interest to be paid at the rate of LIBOR plus a premium of 140 basis points, subject to adjustment based upon changes to our credit ratings. At September 30, 2018 , the annual interest rate payable on amounts outstanding under this term loan was 3.5% . The weighted average annual interest rate for amounts outstanding under this term loan was 3.5% and 2.6% for the three months ended September 30, 2018 and 2017 , respectively, and 3.3% and 2.4% for the nine months ended September 30, 2018 and 2017 , respectively. We incurred interest expense and other associated costs related to this term loan of $3,263 and $2,491 for the three months ended September 30, 2018 and 2017 , respectively, and $9,106 and $6,802 for the nine months ended September 30, 2018 and 2017 , respectively. This term loan includes an accordion feature under which maximum borrowings may be increased to up to $700,000 in certain circumstances. Our $200,000 term loan matures in September 2022, and is prepayable without penalty at any time. This term loan requires annual interest to be paid at the rate of LIBOR plus a premium of 135 basis points, subject to adjustment based upon changes to our credit ratings. At September 30, 2018 , the annual interest rate payable on amounts outstanding under this term loan was 3.6% . The weighted average annual interest rate for amounts outstanding under this term loan was 3.5% and 2.7% for the three months ended September 30, 2018 and 2017 , respectively, and 3.3% and 2.7% for the nine months ended September 30, 2018 and 2017 , respectively. We incurred interest expense and other associated costs related to this term loan of $1,842 and $1,476 for the three months ended September 30, 2018 and 2017 , respectively, and $5,144 and $4,323 for the nine months ended September 30, 2018 and 2017 , respectively. This term loan includes an accordion feature under which maximum borrowings may be increased to up to $400,000 in certain circumstances. Our revolving credit facility and term loan agreements and our senior unsecured notes indentures and their supplements provide for acceleration of payment of all amounts due thereunder upon the occurrence and continuation of certain events of default, such as, in the case of our revolving credit facility and term loan agreements, a change of control of us, as defined, which includes The RMR Group LLC, or RMR LLC, ceasing to act as our business and property manager. Our revolving credit facility and term loan agreements and our senior unsecured notes indentures and their supplements also contain a number of covenants, including covenants that restrict our ability to incur debts, and generally require us to maintain certain financial ratios, and our revolving credit facility and term loan agreements restrict our ability to make distributions under certain circumstances. We believe we were in compliance with the terms and conditions of the respective covenants under our revolving credit facility and term loan agreements and our senior unsecured notes indentures and their supplements at September 30, 2018 .

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities The table below presents certain of our assets measured at fair value at September 30, 2018 , categorized by the level of inputs as defined in the fair value hierarchy under GAAP, used in the valuation of each asset: Fair Value at Reporting Date Using Quoted Prices in Significant Active Markets for Significant Other Unobservable Identical Assets Observable Inputs Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements Assets: Investment in RMR Inc. (1) $ 244,751 $ 244,751 $ — $ — Investment in Five Star (2) $ 3,643 $ 3,643 $ — $ — (1) Our 2,637,408 shares of class A common stock of The RMR Group Inc., or RMR Inc., which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs). Our historical cost basis for these shares is $69,826 as of September 30, 2018 . During the three and nine months ended September 30, 2018 , we recorded an unrealized gain of $37,847 and $88,353 , respectively, to adjust the carrying value of our investment in RMR Inc. class A common shares to their fair value. (2) Our 4,235,000 common shares of Five Star, which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs). Our adjusted cost basis for these shares is $6,353 as of September 30, 2018 . During each of the three and nine months ended September 30, 2018 , we recorded an unrealized loss of $2,710 , to adjust the carrying value of our investment in Five Star common shares to their fair value. During the nine months ended September 30, 2017 , we recorded a loss on impairment of $5,082 to reduce the carrying value of our Five Star investment to its estimated fair value in accordance with applicable GAAP standards at that time. In addition to the assets described in the table above, our financial instruments at September 30, 2018 and December 31, 2017 included cash and cash equivalents, restricted cash, other assets, our revolving credit facility, term loans, senior unsecured notes, secured debt and capital leases and other unsecured obligations and liabilities. The fair values of these financial instruments approximated their carrying values in our condensed consolidated financial statements as of such dates, except as follows: As of September 30, 2018 As of December 31, 2017 Description Carrying Amount (1) Estimated Fair Value Carrying Amount (1) Estimated Fair Value Senior unsecured notes $ 2,215,900 $ 2,256,958 $ 1,725,662 $ 1,810,882 Secured debts (2) 745,269 692,075 805,404 794,047 $ 2,961,169 $ 2,949,033 $ 2,531,066 $ 2,604,929 (1) Includes unamortized debt issuance costs, premiums and discounts. (2) We assumed certain of these secured debts in connection with our acquisitions of certain properties. We recorded the assumed secured debts at estimated fair value on the date of assumption and we are amortizing the fair value adjustments, if any, to interest expense over their respective terms to adjust interest expense to the estimated market interest rates as of the date of assumption. We estimated the fair value of our two issuances of senior unsecured notes due 2042 and 2046 based on the closing price on The Nasdaq Stock Market LLC, or Nasdaq, (a Level 1 input) as of September 30, 2018 . We estimated the fair values of our five issuances of senior unsecured notes due 2019, 2020, 2021, 2024 and 2028 using an average of the bid and ask price on or about September 30, 2018 (Level 2 inputs as defined in the fair value hierarchy under GAAP). We estimated the fair values of our secured debts by using discounted cash flows analyses and currently prevailing market terms as of the measurement date (Level 3 inputs as defined in the fair value hierarchy under GAAP). Because Level 3 inputs are unobservable, our estimated fair value may differ materially from the actual fair value.

Noncontrolling Interest

Noncontrolling Interest	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest In March 2017, we entered a joint venture with a sovereign investor for one of our MOBs ( two buildings) located in Boston, Massachusetts. The investor contributed approximately $261,009 for a 45% equity interest in the joint venture, and we retained the remaining 55% equity interest in the joint venture. Net proceeds from this transaction were approximately $255,931 , after transaction costs. We continue to control this property and therefore continue to account for this property on a consolidated basis in our condensed consolidated financial statements under the VIE model. We recognized a noncontrolling interest in our condensed consolidated balance sheets of approximately $181,859 as of completion of the transaction, which was equal to 45% of the aggregate carrying value of the total equity of the property immediately prior to the transaction. The difference between the net proceeds received from this transaction and the noncontrolling interest recognized, which was approximately $74,072 , was reflected as an increase in additional paid in capital in our condensed consolidated balance sheets upon the closing of the transaction. The portion of the joint venture's net income and comprehensive income not attributable to us, or $1,397 and $1,379 for the three months ended September 30, 2018 and 2017 , respectively, and $4,181 and $2,865 for the nine months ended September 30, 2018 and 2017 , respectively, is reported as noncontrolling interest in our condensed consolidated statements of comprehensive income. We made aggregate cash distributions to our joint venture partner of $5,151 and $5,105 for the three months ended September 30, 2018 and 2017 , respectively, and $15,932 and $8,587 for the nine months ended September 30, 2018 and 2017 , respectively, which are reflected as a decrease in total equity attributable to noncontrolling interest in our condensed consolidated balance sheets. As of September 30, 2018 , this joint venture held real estate assets with an aggregate net book value of $749,830 , subject to mortgage notes of $620,000 . In assessing whether we have a controlling interest in this joint venture arrangement and are required to consolidate the accounts of the joint venture entity, we considered the members' rights to residual gains and obligation to absorb losses, which activities most significantly impact the economic performance of the entity and which member has the power to direct those activities.

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2018
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Share Awards: On March 29, 2018, in accordance with our Trustee compensation arrangements, and in connection with the election of one of our Managing Trustees, we granted 3,000 of our common shares, valued at $15.66 per share, the closing price of our common shares on Nasdaq on that day, to the Managing Trustee who was elected as a Managing Trustee on that day. On May 22, 2018, in accordance with our Trustee compensation arrangements, we granted 3,000 of our common shares, valued at $16.56 per share, the closing price of our common shares on Nasdaq on that day, to each of our five Trustees as part of their annual compensation. On September 13, 2018, we granted an aggregate of 105,800 of our common shares, valued at $19.11 per share, the closing price of our common shares on Nasdaq on that day, to our officers and certain other employees of RMR LLC under our equity compensation plan. Share Purchases: On January 1, 2018, we purchased 4,628 of our common shares, valued at $19.15 per share, the closing price of our common shares on Nasdaq on December 29, 2017, from a former employee of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. On September 24, 2018, we purchased an aggregate of 18,121 of our common shares, valued at $17.56 per share, the closing price of our common shares on Nasdaq on that day, from certain of our officers and other employees of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. On October 2, 2018, we purchased 250 of our common shares, valued at $17.05 per share, the closing price of our common shares on Nasdaq on that day, from a former employee of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. Distributions: On February 22, 2018 , we paid a regular quarterly distribution to common shareholders of $0.39 per share, or approximately $92,674 , that was declared on January 19, 2018 and was payable to shareholders of record on January 29, 2018. On May 17, 2018, we paid a regular quarterly distribution to common shareholders of $0.39 per share, or approximately $92,676 , that was declared on April 19, 2018 and was payable to shareholders of record on April 30, 2018. On August 16, 2018, we paid a regular quarterly distribution to common shareholders of $0.39 per share, or approximately $92,681 , that was declared on July 19, 2018 and was payable to shareholders of record on July 30, 2018. On October 18, 2018, we declared a regular quarterly distribution payable to common shareholders of record on October 29, 2018, of $0.39 per share, or approximately $92,715 . We expect to pay this distribution on or about November 15, 2018.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting As of September 30, 2018 , we have four operating segments, of which three are separate reporting segments. We aggregate the reporting units in each of our MOBs, our triple net leased senior living communities and our managed senior living communities into three reporting segments, based on their similar operating and economic characteristics. The first reporting segment includes MOBs where the tenants pay us rent. The second reporting segment includes triple net leased senior living communities that provide short term and long term residential care and other services for residents and with respect to which we receive rents from the operators. The third reporting segment includes managed senior living communities that provide short term and long term residential care and other services for residents where we pay fees to the operator to manage the communities for our account. The fourth segment includes all of our other operations, including certain properties that offer wellness, fitness and spa services to members and with respect to which we receive rents from operators, which we do not consider to be sufficiently material to constitute a separate reporting segment. For the Three Months Ended September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 104,492 $ 64,538 $ — $ 4,618 $ 173,648 Residents fees and services — — 105,321 — 105,321 Total revenues 104,492 64,538 105,321 4,618 278,969 Expenses: Property operating expenses 32,652 — 83,335 — 115,987 Depreciation and amortization 35,223 20,148 15,341 949 71,661 General and administrative — — — 31,032 31,032 Acquisition and certain other transaction related costs — — — 51 51 Impairment of assets — 4,525 — — 4,525 Total expenses 67,875 24,673 98,676 32,032 223,256 Dividend income — — — 660 660 Unrealized gains and losses on equity securities, net — — — 35,137 35,137 Interest and other income — — — 248 248 Interest expense (6,172 ) (327 ) (997 ) (37,920 ) (45,416 ) Gain on early extinguishment of debt — 76 32 — 108 Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 30,445 39,614 5,680 (29,289 ) 46,450 Income tax expense — — — (79 ) (79 ) Equity in earnings of an investee — — — 831 831 Net income (loss) 30,445 39,614 5,680 (28,537 ) 47,202 Net income attributable to noncontrolling interest (1,397 ) — — — (1,397 ) Net income (loss) attributable to common shareholders $ 29,048 $ 39,614 $ 5,680 $ (28,537 ) $ 45,805 For the Nine Months Ended September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 309,497 $ 198,626 $ — $ 13,838 $ 521,961 Residents fees and services — — 309,981 — 309,981 Total revenues 309,497 198,626 309,981 13,838 831,942 Expenses: Property operating expenses 94,773 — 239,368 — 334,141 Depreciation and amortization 105,934 60,529 44,993 2,844 214,300 General and administrative — — — 85,228 85,228 Acquisition and certain other transaction related costs — — — 138 138 Impairment of assets — 5,073 — — 5,073 Total expenses 200,707 65,602 284,361 88,210 638,880 Gain on sale of properties — 261,916 — — 261,916 Dividend income — — — 1,978 1,978 Unrealized gains and losses on equity securities, net — — — 85,643 85,643 Interest and other income — — — 362 362 Interest expense (18,194 ) (1,463 ) (3,580 ) (110,544 ) (133,781 ) Gain (loss) on early extinguishment of debt — 76 (98 ) — (22 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 90,596 393,553 21,942 (96,933 ) 409,158 Income tax expense — — — (444 ) (444 ) Equity in earnings of an investee — — — 882 882 Net income (loss) 90,596 393,553 21,942 (96,495 ) 409,596 Net income attributable to noncontrolling interest (4,181 ) — — — (4,181 ) Net income (loss) attributable to common shareholders $ 86,415 $ 393,553 $ 21,942 $ (96,495 ) $ 405,415 As of September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Total assets $ 3,408,381 $ 2,121,134 $ 1,351,382 $ 572,547 $ 7,453,444 For the Three Months Ended September 30, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 96,116 $ 67,662 $ — $ 4,570 $ 168,348 Residents fees and services — — 98,325 — 98,325 Total revenues 96,116 67,662 98,325 4,570 266,673 Expenses: Property operating expenses 29,158 — 75,531 — 104,689 Depreciation and amortization 32,351 20,629 12,691 948 66,619 General and administrative — — — 19,883 19,883 Acquisition and certain other transaction related costs — — — 19 19 Total expenses 61,509 20,629 88,222 20,850 191,210 Dividend income — — — 659 659 Interest and other income — — — 128 128 Interest expense (6,172 ) (655 ) (1,172 ) (32,106 ) (40,105 ) Loss on early extinguishment of debt — — — (274 ) (274 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 28,435 46,378 8,931 (47,873 ) 35,871 Income tax expense — — — (109 ) (109 ) Equity in earnings of an investee — — — 31 31 Net income (loss) 28,435 46,378 8,931 (47,951 ) 35,793 Net income attributable to noncontrolling interest (1,379 ) — — — (1,379 ) Net income (loss) attributable to common shareholders $ 27,056 $ 46,378 $ 8,931 $ (47,951 ) $ 34,414 For the Nine Months Ended September 30, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 285,413 $ 202,340 $ — $ 13,684 $ 501,437 Residents fees and services — — 294,748 — 294,748 Total revenues 285,413 202,340 294,748 13,684 796,185 Expenses: Property operating expenses 83,980 — 224,670 — 308,650 Depreciation and amortization 95,890 61,434 49,295 2,844 209,463 General and administrative — — — 57,880 57,880 Acquisition and certain other transaction related costs — — — 148 148 Impairment of assets — — — 5,082 5,082 Total expenses 179,870 61,434 273,965 65,954 581,223 Dividend income — — — 1,978 1,978 Interest and other income — — — 323 323 Interest expense (18,742 ) (8,205 ) (3,523 ) (93,924 ) (124,394 ) Loss on early extinguishment of debt (59 ) (7,294 ) — (274 ) (7,627 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 86,742 125,407 17,260 (144,167 ) 85,242 Income tax expense — — — (300 ) (300 ) Equity in earnings of an investee — — — 533 533 Net income (loss) 86,742 125,407 17,260 (143,934 ) 85,475 Net income attributable to noncontrolling interest (2,865 ) — — — (2,865 ) Net income (loss) attributable to common shareholders $ 83,877 $ 125,407 $ 17,260 $ (143,934 ) $ 82,610 As of December 31, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Total assets $ 3,367,485 $ 2,251,756 $ 1,273,757 $ 401,021 $ 7,294,019

Leases and Management Agreement

Leases and Management Agreements with Five Star	9 Months Ended
	Sep. 30, 2018
Risks and Uncertainties [Abstract]
Leases and Management Agreements with Five Star	Leases and Management Agreements with Five Star Our Senior Living Communities Leased by Five Star. We are Five Star’s largest landlord and Five Star is our largest tenant. As of September 30, 2018 and 2017 , we leased 184 and 185 senior living communities to Five Star, respectively. We lease senior living communities to Five Star pursuant to five leases. We recognized total rental income payable by Five Star of $51,757 and $51,333 for the three months ended September 30, 2018 and 2017 , respectively, and $155,207 and $153,441 for the nine months ended September 30, 2018 and 2017 , respectively. These amounts exclude percentage rent payments we received from Five Star of $1,386 and $1,353 for the three months ended September 30, 2018 and 2017 , respectively, and $4,050 and $4,190 for the nine months ended September 30, 2018 and 2017 , respectively. We determine actual percentage rent due under our Five Star leases annually and recognize any resulting amount as rental income at year end when all contingencies are met. As of September 30, 2018 and December 31, 2017 , we had rents receivable from Five Star of $17,256 and $18,539 , respectively, which amounts are included in other assets in our condensed consolidated balance sheets. Rental income from Five Star represented 18.6% and 18.7% of our total revenues for the three and nine months ended September 30, 2018 , respectively, and the properties Five Star leases from us represented 27.0% of our real estate investments, at cost, as of September 30, 2018 . Pursuant to the terms of our leases with Five Star, for the nine months ended September 30, 2018 and 2017 , we funded $14,749 and $30,698 , respectively, of improvements to communities leased to Five Star. As a result, the annual minimum rent payable to us by Five Star increased by approximately $1,177 and $2,464 as of September 30, 2018 and 2017 , respectively. Our Senior Living Communities Managed by Five Star . As of September 30, 2018 and 2017 , Five Star managed 75 and 68 senior living communities for our account, respectively. We lease our senior living communities that are managed by Five Star and include assisted living units or SNF units to our TRSs and Five Star manages these communities pursuant to long term management agreements. See Note 3 above for certain senior living communities we acquired since December 2017 and which are managed by Five Star for our account. In addition, in June 2018, Five Star began managing for our account, pursuant to a management agreement and our existing Pooling Agreement No. 12 with Five Star, as amended and restated, a senior living community we own located in California with 98 living units after the previous tenant defaulted on its lease with us. We incurred management fees payable to Five Star of $3,666 and $3,414 for the three months ended September 30, 2018 and 2017 , respectively, and $10,694 and $10,531 for the nine months ended September 30, 2018 and 2017 , respectively. These amounts are included in property operating expenses or have been capitalized, as appropriate, in our condensed consolidated financial statements. In November 2018, Five Star began managing for our account, pursuant to a management agreement with Five Star, a senior living community we own located in Colorado with 238 living units after the previous tenant defaulted on its lease with us. Five Star also provides certain other services directly to residents at some of the senior living communities it manages for us, such as rehabilitation services. At senior living communities Five Star manages for us where Five Star provides rehabilitation services on an outpatient basis, the residents, third party payers or government programs pay Five Star for those rehabilitation services. At senior living communities Five Star manages for us where Five Star provides both inpatient and outpatient rehabilitation services, we generally pay Five Star for these services and charges for these services are included in amounts charged to residents, third party payers or government programs. We incurred fees payable to Five Star of $1,584 and $1,841 for the three months ended September 30, 2018 and 2017 , respectively, and $4,944 and $5,709 for the nine months ended September 30, 2018 and 2017, respectively, for rehabilitation services Five Star provided at senior living communities it manages for us; we include these amounts in property operating expenses in our condensed consolidated statement of comprehensive income.

Business and Property Managemen

Business and Property Management Agreements with RMR LLC	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Business and Property Management Agreements with RMR LLC	Business and Property Management Agreements with RMR LLC We have no employees. The personnel and various services we require to operate our business are provided to us by RMR LLC. We have two agreements with RMR LLC to provide management services to us: (1) a business management agreement, which relates to our business generally; and (2) a property management agreement, which relates to the property level operations of our MOBs. We also have a subsidiary level management agreement with RMR LLC related to one of our MOBs located in Boston, Massachusetts, which we entered in connection with the joint venture arrangement for that MOB. Under that agreement, our subsidiary pays RMR LLC certain business management fees directly, which fees are credited against the business management fees payable by us to RMR LLC. Pursuant to our business management agreement with RMR LLC, we recognized net business management fees of $28,306 and $17,744 for the three months ended September 30, 2018 and 2017 , respectively, and $78,119 and $50,956 for the nine months ended September 30, 2018 and 2017 , respectively. The net business management fees we recognized for the three and nine months ended September 30, 2018 include $725 and $2,175 , respectively, of management fees related to our subsidiary level management agreement with RMR LLC entered in connection with our joint venture arrangement and $18,751 and $50,708 , respectively, of estimated 2018 incentive fees based on our common share total return, as defined in our business management agreement, as of September 30, 2018 . Although we recognized estimated incentive fees in accordance with GAAP, the actual amount of incentive fees for 2018, if any, will be based on our common share total return, as defined in our business management agreement, for the three year period ending December 31, 2018, and will be payable in 2019. The net business management fees for the three and nine months ended September 30, 2017 , included $725 and $1,512 , respectively, of management fees related to our subsidiary level management agreement with RMR LLC and $8,022 and $22,048 , respectively, of estimated 2017 incentive fees based on our common share total return, as defined in our business management agreement, as of September 30, 2017 . In January 2018, we paid RMR LLC an incentive fee of $55,740 for 2017. These amounts are included in general and administrative expenses in our condensed consolidated statements of comprehensive income. Pursuant to our property management agreement with RMR LLC, we recognized aggregate net property management and construction supervision fees of $3,025 and $2,736 for the three months ended September 30, 2018 and 2017 , respectively, and $8,829 and $8,034 for the nine months ended September 30, 2018 and 2017 , respectively. These amounts are included in property operating expenses or have been capitalized, as appropriate, in our condensed consolidated financial statements. We are generally responsible for all of our operating expenses, including certain expenses incurred by RMR LLC on our behalf. Our property level operating expenses, including certain payroll and related costs incurred by RMR LLC, are generally incorporated into rents charged to our tenants. We reimbursed RMR LLC $3,440 and $2,353 for property management related expenses for the three months ended September 30, 2018 and 2017 , respectively, and $9,391 and $7,116 for the nine months ended September 30, 2018 and 2017 , respectively, which amounts are included in property operating expenses in our condensed consolidated statements of comprehensive income. In addition, we are responsible for our share of RMR LLC's costs for providing our internal audit function. The amounts recognized as expense for internal audit costs were $35 and $72 for the three months ended September 30, 2018 and 2017 , respectively, and $173 and $206 for the nine months ended September 30, 2018 and 2017 , respectively, which amounts are included in general and administrative expenses in our condensed consolidated statements of comprehensive income.

Related Person Transactions

Related Person Transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with Five Star, RMR LLC, RMR Inc., Affiliates Insurance Company, or AIC, and others related to them, including other companies to which RMR LLC provides management services and which have trustees, directors and officers who are also our Trustees or officers. Five Star. We are currently one of Five Star’s largest stockholders. As of September 30, 2018 , we owned 4,235,000 of Five Star’s common shares, or approximately 8.4% of Five Star’s outstanding common shares. Five Star is our largest tenant and the manager of our managed senior living communities. RMR LLC provides management services to both us and Five Star. As of September 30, 2018 , a subsidiary of ABP Trust, the controlling shareholder of RMR Inc., owned 35.6% of Five Star's outstanding common shares. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee of ABP Trust and a managing director of Five Star. See Note 9 for further information regarding our relationships, agreements and transactions with Five Star and Note 5 for further information regarding our investment in Five Star. Our Manager, RMR LLC. We have two agreements with RMR LLC to provide management services to us. See Note 10 for further information regarding our management agreements with RMR LLC. We have historically granted share awards to our officers and other employees of RMR LLC under our equity compensation plans. In September 2018 and 2017, we granted annual awards of 105,800 and 88,100 of our common shares, respectively, to our officers and other employees of RMR LLC. In September 2018 and 2017, we purchased 18,121 and 16,654 of our common shares, respectively, valued at the closing price of our common shares on Nasdaq on the applicable date of purchase, in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares to certain employees of RMR LLC. We include the amounts recognized as expense for share awards to our officers and other RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income. RMR Inc. RMR LLC is a majority owned subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., a managing director, president and chief executive officer of RMR Inc., and an officer of RMR LLC. Jennifer B. Clark, our other Managing Trustee, also serves as a managing director and as executive vice president, general counsel and secretary of RMR Inc. and an officer of ABP Trust and RMR LLC. Other officers of RMR LLC also serve as our officers. As of September 30, 2018 , we owned 2,637,408 shares of class A common stock of RMR Inc. See Note 5 for further information regarding our investment in RMR Inc. AIC. We, ABP Trust, Five Star and four other companies to which RMR LLC provides management services currently own AIC in equal amounts. We and the other AIC shareholders participate in a combined property insurance program arranged and reinsured in part by AIC; we also have a one year standalone insurance policy that provides coverage for our MOB ( two buildings) located in Boston, Massachusetts that is owned in our joint venture arrangement, which we obtained as a part of this insurance program. We (including our consolidated joint venture) paid aggregate annual premiums, including taxes and fees, of approximately $4,413 in connection with the renewal of this insurance program for the policy year ending June 30, 2019. The amount of premiums may be adjusted from time to time as we acquire and dispose of properties that are included in this insurance program. As of September 30, 2018 and December 31, 2017 , our investment in AIC had a carrying value of $9,157 and $8,185 , respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which is presented as equity in earnings of an investee in our condensed consolidated statements of comprehensive income. Our other comprehensive income includes our proportionate part of unrealized gains on securities that are owned by AIC related to our investment in AIC. For further information about these and other such relationships and certain other related person transactions, refer to our Annual Report.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have elected to be taxed as a real estate investment trust, or REIT, under the Internal Revenue Code of 1986, as amended, and as such, are generally not subject to federal and most state income taxation on our operating income provided we distribute our taxable income to our shareholders and meet certain organization and operating requirements. We do, however, lease certain managed senior living communities to our wholly owned TRSs that, unlike most of our subsidiaries, file a separate consolidated federal corporate income tax return and are subject to federal and state income taxes. Our consolidated income tax provision includes the income tax provision related to the operations of our TRSs and certain state income taxes we incur despite our taxation as a REIT. During the three months ended September 30, 2018 and 2017 , we recognized income tax expense of $79 and $109 , respectively, and during the nine months ended September 30, 2018 and 2017 , we recognized income tax expense of $444 and $300 , respectively.

Weighted Average Common Shares

Weighted Average Common Shares	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Weighted Average Common Shares	Weighted Average Common Shares The following table provides a reconciliation of the weighted average number of common shares used in the calculation of basic and diluted earnings per share (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Weighted average common shares for basic earnings per share 237,511 237,421 237,492 237,404 Effect of dilutive securities: unvested share awards 51 39 34 41 Weighted average common shares for diluted earnings per share 237,562 237,460 237,526 237,445

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements On January 1, 2018, we adopted FASB Accounting Standards Update, or ASU, No. 2014-09 (and related clarifying guidance issued by the FASB), Revenue From Contracts With Customers, which outlines a comprehensive model for entities to use in accounting for revenue arising from contracts with customers. ASU No. 2014-09 states that “an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.” While ASU No. 2014-09 specifically references contracts with customers, it may apply to certain other transactions such as the sale of real estate or equipment. A substantial portion of our total revenues, including residents fees and services which relate to contracts with residents for housing services at properties leased to our taxable REIT subsidiaries, or TRSs, consists of rental income from leasing arrangements, which is specifically excluded from ASU No. 2014-09. Our contracts with residents that are within the scope of ASU No. 2014-09 are generally short term in nature. We have adopted ASU No. 2014-09 using the modified retrospective approach. The adoption of ASU No. 2014-09 did not have a material impact on the amount or timing of our revenue recognition in our condensed consolidated financial statements. On January 1, 2018, we adopted FASB ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, which changes how entities measure certain equity investments and present changes in the fair value of financial liabilities measured under the fair value option that are attributable to their own credit. The implementation of ASU No. 2016-01 resulted in the reclassification of historical changes in the fair value of our available for sale equity securities of $86,572 from cumulative other comprehensive income to cumulative net income. We also reclassified $841 from cumulative other comprehensive income to cumulative net income for our share of cumulative other comprehensive income of our equity method investee. Effective January 1, 2018, changes in the fair value of our equity securities are recorded through earnings in accordance with ASU No. 2016-01. On January 1, 2018, we adopted FASB ASU No. 2016-18, Restricted Cash , which requires companies to show the changes in the total of cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. ASU No. 2016-18 also requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. As a result, amounts included in restricted cash in our condensed consolidated balance sheets are presented with cash and cash equivalents in our condensed consolidated statements of cash flows to the related captions in the condensed consolidated balance sheets. Restricted cash totaled $108,335 and $14,088 as of September 30, 2018 and 2017 , respectively. The implementation of ASU No. 2016-18 resulted in a $10,259 increase to net cash provided by operating activities for the nine months ended September 30, 2017 . The adoption of ASU No. 2016-18 did not change our balance sheet presentation. In February 2016, the FASB issued ASU No. 2016-02, Leases , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). ASU No. 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease. A lessee is also required to record a right of use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales type leases, direct financing leases and operating leases. ASU No. 2016-02 is effective for reporting periods beginning after December 15, 2018, with early adoption permitted. We are currently assessing the potential impact the adoption of ASU No. 2016-02 will have in our condensed consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) : Measurement of Credit Losses on Financial Instruments , which requires that entities use a new forward looking “expected loss” model that generally will result in the earlier recognition of allowance for credit losses. The measurement of expected credit losses is based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU No. 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2016-13 will have in our condensed consolidated financial statements. We currently expect to adopt the standard using the modified retrospective approach. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees, with certain exceptions. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2018-07 will have in our condensed consolidated financial statements.

Real Estate Properties (Tables)

Real Estate Properties (Tables)	9 Months Ended
	Sep. 30, 2018
Real Estate [Abstract]
Schedule of real estate property acquisition	The table below represents the purchase price allocations (including net closing adjustments) of the senior living community acquisitions that closed during the nine months ended September 30, 2018 , as described above: Date Location Leased/Managed Number of Properties Units Cash Paid Plus Assumed Debt (1) Land Building and Improvements FF&E Acquired Real Estate Intangible Assets Assumed Debt Premium on Assumed Debt January 2018 Tennessee Managed 1 88 $ 19,868 $ 580 $ 14,884 $ 1,209 $ 3,195 $ — $ — February 2018 Arizona Managed 1 127 22,622 2,017 17,123 390 4,451 16,748 (1,359 ) June 2018 Tennessee Managed 2 151 23,860 965 17,910 1,628 3,843 16,588 (486 ) 4 366 $ 66,350 $ 3,562 $ 49,917 $ 3,227 $ 11,489 $ 33,336 $ (1,845 ) (1) Cash paid plus assumed debt, if any, includes closing costs. The table below represents the purchase price allocations (including net closing adjustments) of the MOB acquisitions that closed during the nine months ended September 30, 2018 , as described above: Date Location Number of Properties Number of Buildings Square Feet (000’s) Cash Paid Plus Assumed Debt (1) Land Building and Improvements Acquired Real Estate Leases (2) Assumed Debt January 2018 3 States 3 3 400 $ 91,698 $ 16,873 $ 54,605 $ 20,220 $ — March 2018 Virginia 1 1 135 23,275 2,863 11,105 9,307 11,050 4 4 535 $ 114,973 $ 19,736 $ 65,710 $ 29,527 $ 11,050 (1) Cash paid plus assumed debt, if any, includes closing costs. (2) The weighted average amortization period for acquired real estate leases as of the acquisition dates was 5.8 years.

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Assets and liabilities recurring and nonrecurring measured at fair value	The table below presents certain of our assets measured at fair value at September 30, 2018 , categorized by the level of inputs as defined in the fair value hierarchy under GAAP, used in the valuation of each asset: Fair Value at Reporting Date Using Quoted Prices in Significant Active Markets for Significant Other Unobservable Identical Assets Observable Inputs Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements Assets: Investment in RMR Inc. (1) $ 244,751 $ 244,751 $ — $ — Investment in Five Star (2) $ 3,643 $ 3,643 $ — $ — (1) Our 2,637,408 shares of class A common stock of The RMR Group Inc., or RMR Inc., which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs). Our historical cost basis for these shares is $69,826 as of September 30, 2018 . During the three and nine months ended September 30, 2018 , we recorded an unrealized gain of $37,847 and $88,353 , respectively, to adjust the carrying value of our investment in RMR Inc. class A common shares to their fair value. (2) Our 4,235,000 common shares of Five Star, which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs). Our adjusted cost basis for these shares is $6,353 as of September 30, 2018 . During each of the three and nine months ended September 30, 2018 , we recorded an unrealized loss of $2,710 , to adjust the carrying value of our investment in Five Star common shares to their fair value. During the nine months ended September 30, 2017 , we recorded a loss on impairment of $5,082 to reduce the carrying value of our Five Star investment to its estimated fair value in accordance with applicable GAAP standards at that time.
Schedule of carrying value and fair value of the financial instruments	The fair values of these financial instruments approximated their carrying values in our condensed consolidated financial statements as of such dates, except as follows: As of September 30, 2018 As of December 31, 2017 Description Carrying Amount (1) Estimated Fair Value Carrying Amount (1) Estimated Fair Value Senior unsecured notes $ 2,215,900 $ 2,256,958 $ 1,725,662 $ 1,810,882 Secured debts (2) 745,269 692,075 805,404 794,047 $ 2,961,169 $ 2,949,033 $ 2,531,066 $ 2,604,929 (1) Includes unamortized debt issuance costs, premiums and discounts. (2) We assumed certain of these secured debts in connection with our acquisitions of certain properties. We recorded the assumed secured debts at estimated fair value on the date of assumption and we are amortizing the fair value adjustments, if any, to interest expense over their respective terms to adjust interest expense to the estimated market interest rates as of the date of assumption.

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of segment reporting information	For the Three Months Ended September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 104,492 $ 64,538 $ — $ 4,618 $ 173,648 Residents fees and services — — 105,321 — 105,321 Total revenues 104,492 64,538 105,321 4,618 278,969 Expenses: Property operating expenses 32,652 — 83,335 — 115,987 Depreciation and amortization 35,223 20,148 15,341 949 71,661 General and administrative — — — 31,032 31,032 Acquisition and certain other transaction related costs — — — 51 51 Impairment of assets — 4,525 — — 4,525 Total expenses 67,875 24,673 98,676 32,032 223,256 Dividend income — — — 660 660 Unrealized gains and losses on equity securities, net — — — 35,137 35,137 Interest and other income — — — 248 248 Interest expense (6,172 ) (327 ) (997 ) (37,920 ) (45,416 ) Gain on early extinguishment of debt — 76 32 — 108 Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 30,445 39,614 5,680 (29,289 ) 46,450 Income tax expense — — — (79 ) (79 ) Equity in earnings of an investee — — — 831 831 Net income (loss) 30,445 39,614 5,680 (28,537 ) 47,202 Net income attributable to noncontrolling interest (1,397 ) — — — (1,397 ) Net income (loss) attributable to common shareholders $ 29,048 $ 39,614 $ 5,680 $ (28,537 ) $ 45,805 For the Nine Months Ended September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 309,497 $ 198,626 $ — $ 13,838 $ 521,961 Residents fees and services — — 309,981 — 309,981 Total revenues 309,497 198,626 309,981 13,838 831,942 Expenses: Property operating expenses 94,773 — 239,368 — 334,141 Depreciation and amortization 105,934 60,529 44,993 2,844 214,300 General and administrative — — — 85,228 85,228 Acquisition and certain other transaction related costs — — — 138 138 Impairment of assets — 5,073 — — 5,073 Total expenses 200,707 65,602 284,361 88,210 638,880 Gain on sale of properties — 261,916 — — 261,916 Dividend income — — — 1,978 1,978 Unrealized gains and losses on equity securities, net — — — 85,643 85,643 Interest and other income — — — 362 362 Interest expense (18,194 ) (1,463 ) (3,580 ) (110,544 ) (133,781 ) Gain (loss) on early extinguishment of debt — 76 (98 ) — (22 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 90,596 393,553 21,942 (96,933 ) 409,158 Income tax expense — — — (444 ) (444 ) Equity in earnings of an investee — — — 882 882 Net income (loss) 90,596 393,553 21,942 (96,495 ) 409,596 Net income attributable to noncontrolling interest (4,181 ) — — — (4,181 ) Net income (loss) attributable to common shareholders $ 86,415 $ 393,553 $ 21,942 $ (96,495 ) $ 405,415 As of September 30, 2018 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Total assets $ 3,408,381 $ 2,121,134 $ 1,351,382 $ 572,547 $ 7,453,444 For the Three Months Ended September 30, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 96,116 $ 67,662 $ — $ 4,570 $ 168,348 Residents fees and services — — 98,325 — 98,325 Total revenues 96,116 67,662 98,325 4,570 266,673 Expenses: Property operating expenses 29,158 — 75,531 — 104,689 Depreciation and amortization 32,351 20,629 12,691 948 66,619 General and administrative — — — 19,883 19,883 Acquisition and certain other transaction related costs — — — 19 19 Total expenses 61,509 20,629 88,222 20,850 191,210 Dividend income — — — 659 659 Interest and other income — — — 128 128 Interest expense (6,172 ) (655 ) (1,172 ) (32,106 ) (40,105 ) Loss on early extinguishment of debt — — — (274 ) (274 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 28,435 46,378 8,931 (47,873 ) 35,871 Income tax expense — — — (109 ) (109 ) Equity in earnings of an investee — — — 31 31 Net income (loss) 28,435 46,378 8,931 (47,951 ) 35,793 Net income attributable to noncontrolling interest (1,379 ) — — — (1,379 ) Net income (loss) attributable to common shareholders $ 27,056 $ 46,378 $ 8,931 $ (47,951 ) $ 34,414 For the Nine Months Ended September 30, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Revenues: Rental income $ 285,413 $ 202,340 $ — $ 13,684 $ 501,437 Residents fees and services — — 294,748 — 294,748 Total revenues 285,413 202,340 294,748 13,684 796,185 Expenses: Property operating expenses 83,980 — 224,670 — 308,650 Depreciation and amortization 95,890 61,434 49,295 2,844 209,463 General and administrative — — — 57,880 57,880 Acquisition and certain other transaction related costs — — — 148 148 Impairment of assets — — — 5,082 5,082 Total expenses 179,870 61,434 273,965 65,954 581,223 Dividend income — — — 1,978 1,978 Interest and other income — — — 323 323 Interest expense (18,742 ) (8,205 ) (3,523 ) (93,924 ) (124,394 ) Loss on early extinguishment of debt (59 ) (7,294 ) — (274 ) (7,627 ) Income (loss) from continuing operations before income tax expense and equity in earnings of an investee 86,742 125,407 17,260 (144,167 ) 85,242 Income tax expense — — — (300 ) (300 ) Equity in earnings of an investee — — — 533 533 Net income (loss) 86,742 125,407 17,260 (143,934 ) 85,475 Net income attributable to noncontrolling interest (2,865 ) — — — (2,865 ) Net income (loss) attributable to common shareholders $ 83,877 $ 125,407 $ 17,260 $ (143,934 ) $ 82,610 As of December 31, 2017 MOBs Triple Net Leased Senior Living Communities Managed Senior Living Communities All Other Operations Consolidated Total assets $ 3,367,485 $ 2,251,756 $ 1,273,757 $ 401,021 $ 7,294,019

Weighted Average Common Shares

Weighted Average Common Shares (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of weighted average number of shares	The following table provides a reconciliation of the weighted average number of common shares used in the calculation of basic and diluted earnings per share (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Weighted average common shares for basic earnings per share 237,511 237,421 237,492 237,404 Effect of dilutive securities: unvested share awards 51 39 34 41 Weighted average common shares for diluted earnings per share 237,562 237,460 237,526 237,445

Basis of Presentation (Details)

Basis of Presentation (Details) $ in Thousands	1 Months Ended
	Mar. 31, 2017buildingproperty	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of properties included in joint venture agreement | property	1
Number of buildings included in joint venture agreement | building	2
Variable interest entity, consolidated, carrying amount, assets		$ 1,070,402	$ 1,102,986
Variable interest entity, consolidated, carrying amount, liabilities		$ 714,635	$ 720,678

Recent Accounting Pronounceme_3

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from accumulated other comprehensive income		$ 0	$ 0	$ 0	$ (5,082)
Restricted cash		$ 108,335	14,088	108,335	14,088
Net cash provided by operating activities				$ 286,022	$ 334,649
AOCI Attributable to Parent | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect from other comprehensive income to retained earnings	$ (86,572)
Reclassification from accumulated other comprehensive income	(841)
Retained Earnings | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect from other comprehensive income to retained earnings	86,572
Reclassification from accumulated other comprehensive income	$ 841
Restatement Adjustment | Accounting Standards Update 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities			$ 10,259

Real Estate Properties - Narrat

Real Estate Properties - Narrative (Details) ft² in Thousands	1 Months Ended														3 Months Ended		9 Months Ended
	Jun. 30, 2018USD ($)living_unitnursing_facilitycommunityproperty	May 31, 2018USD ($)community	Mar. 31, 2018USD ($)ft²buildingcommunityproperty	Feb. 28, 2018living_unit	Feb. 28, 2018USD ($)	Feb. 28, 2018community	Feb. 28, 2018property	Jan. 31, 2018ft²living_unit	Jan. 31, 2018ft²building	Jan. 31, 2018USD ($)ft²	Jan. 31, 2018ft²community	Jan. 31, 2018ft²property	Dec. 31, 2017USD ($)living_unitproperty	Nov. 30, 2017property	Sep. 30, 2018USD ($)ft²statebuildingcommunityproperty	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)ft²stateliving_unitbuildingcommunityproperty	Sep. 30, 2017USD ($)
Real Estate Properties
Number of properties owned | property															443		443
Number of buildings owned | building															469		469
Number of states in which properties are located | state															42		42
Assumed debt																	$ 44,386,000	$ 0
Impairment of assets															$ 4,525,000	$ 0	5,073,000	5,082,000
Gain on sale of properties															$ 0	$ 0	261,916,000	0
Proceeds from sale of properties																	$ 332,389,000	0
Discontinued Operations, Disposed of by Sale
Real Estate Properties
Gain on sale of properties	$ 2,150,000
Impairment of real estate																		$ 0
Acquisition | MOBs
Real Estate Properties
Number of properties | property																	4
Number of buildings | building																	4
Cash paid plus assumed debt																	$ 114,973,000
Area of real estate properties (in square feet) | ft²															535		535
Assumed debt																	$ 11,050,000
Acquisition | MOBs | Kansas, Missouri And California
Real Estate Properties
Number of properties | property												3
Number of buildings | building									3
Cash paid plus assumed debt										$ 91,698,000
Area of real estate properties (in square feet) | ft²								400	400	400	400	400
Assumed debt										$ 0
Acquisition and certain other transaction related costs										544,000
Acquisition | MOBs | Virginia
Real Estate Properties
Number of properties | property			1
Number of buildings | building			1
Cash paid plus assumed debt			$ 23,275,000
Area of real estate properties (in square feet) | ft²			135
Assumed debt			$ 11,050,000
Acquisition and certain other transaction related costs			525,000
Acquisition | Five Star | Senior Living Communities
Real Estate Properties
Number of properties	2													6			4
Cash paid plus assumed debt																	$ 66,350,000
Assumed debt	$ 16,588,000																$ 33,336,000
Number of acquired private pay independent living units | living_unit																	366
Purchase price excluding closing costs	23,860,000
Acquisition and certain other transaction related costs	$ 560,000
Acquisition | Five Star | Senior Living Communities | Alabama and Indiana
Real Estate Properties
Number of properties | property													2
Number of acquired private pay independent living units | living_unit													229
Purchase price excluding closing costs													$ 39,457,000
Acquisition and certain other transaction related costs													$ 307,000
Acquisition | Five Star | Senior Living Communities | Tennessee
Real Estate Properties
Number of properties	2										1	1
Cash paid plus assumed debt	$ 23,860,000									19,868,000
Assumed debt	$ 16,588,000									0
Number of acquired private pay independent living units | living_unit	151							88
Purchase price excluding closing costs										19,868,000
Acquisition and certain other transaction related costs										$ 201,000
Acquisition | Five Star | Senior Living Communities | Arizona
Real Estate Properties
Number of properties						1	1
Cash paid plus assumed debt					$ 22,622,000
Assumed debt					16,748,000
Number of acquired private pay independent living units | living_unit				127
Purchase price excluding closing costs					22,622,000
Acquisition and certain other transaction related costs					$ 372,000
Sunrise Senior Living LLC | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Senior Living Communities
Real Estate Properties
Gain on sale of properties		$ 78,856,000	$ 181,154,000
Number of communities sold | community		1	2
Proceeds from sale of properties		$ 96,000,000	$ 217,000,000														$ 94,348,000
Rental income recognized															$ 0		$ 3,505,000
Number of real estate properties held-for-sale | community															3		3
Sunrise Senior Living LLC | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Skilled Nursing Facility
Real Estate Properties
Gain on sale of properties	$ 1,906,000
Proceeds from sale of properties	21,865,000
Rental income recognized	$ 650,000														$ 0		$ 664,000
Number of real estate properties held-for-sale | nursing_facility	1

Real Estate Properties - Schedu

Real Estate Properties - Schedule of Purchase Price Allocations (Details) ft² in Thousands, $ in Thousands	1 Months Ended		9 Months Ended
	Mar. 31, 2018USD ($)ft²buildingproperty	Jan. 31, 2018USD ($)ft²buildingproperty	Sep. 30, 2018USD ($)ft²buildingproperty	Sep. 30, 2017USD ($)
Real Estate [Line Items]
Assumed Debt			$ 44,386	$ 0
Acquisition | MOBs
Real Estate [Line Items]
Number of Properties | property			4
Number of Buildings | building			4
Area of real estate properties (in square feet) | ft²			535
Cash Paid Plus Assumed Debt			$ 114,973
Acquired Real Estate Intangible Assets			29,527
Assumed Debt			11,050
Kansas, Missouri And California | Acquisition | MOBs
Real Estate [Line Items]
Number of Properties | property		3
Number of Buildings | building		3
Area of real estate properties (in square feet) | ft²		400
Cash Paid Plus Assumed Debt		$ 91,698
Acquired Real Estate Intangible Assets		20,220
Assumed Debt		0
Virginia | Acquisition | MOBs
Real Estate [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Area of real estate properties (in square feet) | ft²	135
Cash Paid Plus Assumed Debt	$ 23,275
Acquired Real Estate Intangible Assets	9,307
Assumed Debt	11,050
Land | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment			19,736
Land | Kansas, Missouri And California | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment		16,873
Land | Virginia | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment	2,863
Building and Improvements | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment			$ 65,710
Building and Improvements | Kansas, Missouri And California | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment		$ 54,605
Building and Improvements | Virginia | Acquisition | MOBs
Real Estate [Line Items]
Real estate properties acquired, property plant and equipment	$ 11,105
Lease Agreements | Acquisition | MOBs
Real Estate [Line Items]
Weighted average amortization period			5 years 9 months 18 days

Real Estate Properties - Acquis

Real Estate Properties - Acquisitions (Details) $ in Thousands	1 Months Ended										9 Months Ended
	Jun. 30, 2018USD ($)living_unitcommunityproperty	Feb. 28, 2018USD ($)living_unit	Feb. 28, 2018USD ($)	Feb. 28, 2018USD ($)community	Feb. 28, 2018USD ($)property	Jan. 31, 2018USD ($)living_unit	Jan. 31, 2018USD ($)	Jan. 31, 2018USD ($)community	Jan. 31, 2018USD ($)property	Nov. 30, 2017property	Sep. 30, 2018USD ($)living_unitproperty	Sep. 30, 2017USD ($)
Real Estate Properties
Assumed Debt											$ 44,386	$ 0
Five Star | Acquisition | Senior Living Communities
Real Estate Properties
Number of Properties	2									6	4
Units | living_unit											366
Cash Paid Plus Assumed Debt											$ 66,350
Acquired Real Estate Intangible Assets											11,489
Assumed Debt	$ 16,588										33,336
Premium on Assumed Debt											(1,845)
Five Star | Acquisition | Tennessee | Senior Living Communities
Real Estate Properties
Number of Properties	2							1	1
Units | living_unit	151					88
Cash Paid Plus Assumed Debt	$ 23,860						$ 19,868
Acquired Real Estate Intangible Assets						$ 3,195	3,195	$ 3,195	$ 3,195		3,843
Assumed Debt	16,588						0
Premium on Assumed Debt	(486)						0
Five Star | Acquisition | Arizona | Senior Living Communities
Real Estate Properties
Number of Properties				1	1
Units | living_unit		127
Cash Paid Plus Assumed Debt			$ 22,622
Acquired Real Estate Intangible Assets		$ 4,451	4,451	$ 4,451	$ 4,451
Assumed Debt			16,748
Premium on Assumed Debt			(1,359)
Five Star | Acquisition | Land | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment											3,562
Five Star | Acquisition | Land | Tennessee | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment	965						580
Five Star | Acquisition | Land | Arizona | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment			2,017
Five Star | Acquisition | Building and Improvements | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment											49,917
Five Star | Acquisition | Building and Improvements | Tennessee | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment	17,910						14,884
Five Star | Acquisition | Building and Improvements | Arizona | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment			17,123
Five Star | Acquisition | FF&E | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment											$ 3,227
Five Star | Acquisition | FF&E | Tennessee | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment	$ 1,628						$ 1,209
Five Star | Acquisition | FF&E | Arizona | Senior Living Communities
Real Estate Properties
Real estate properties acquired, property plant and equipment			$ 390

Indebtedness (Details)

Indebtedness (Details)	1 Months Ended		3 Months Ended		9 Months Ended
	Jul. 31, 2018USD ($)property	Feb. 28, 2018USD ($)	Sep. 30, 2018USD ($)propertybuildingnote	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)propertybuildingnote	Sep. 30, 2017USD ($)	Nov. 05, 2018USD ($)	Jan. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Indebtedness
Total real estate properties, gross			$ 8,017,214,000		$ 8,017,214,000				$ 7,824,763,000
Unsecured revolving credit facility			195,000,000		195,000,000				$ 596,000,000
Unsecured revolving credit facility
Indebtedness
Unsecured revolving credit facility, maximum borrowing capacity			$ 1,000,000,000		$ 1,000,000,000
Number of public issues of unsecured senior notes | note			7		7
Line of credit facility, periodic payment, principal					$ 0
Revolving credit facility, interest rate payable (as a percent)			3.40%		3.40%
Weighted average interest rate on debt (as a percent)			3.20%	2.50%	2.90%	2.30%
Unsecured revolving credit facility			$ 195,000,000		$ 195,000,000
Revolving credit facility, available amount			805,000,000		805,000,000
Interest expense and other associated costs incurred			2,291,000	$ 3,929,000	7,872,000	$ 9,888,000
Maximum borrowing capacity that may be increased (up to)			2,000,000,000		$ 2,000,000,000
Unsecured revolving credit facility | LIBOR
Indebtedness
Interest rate added to the base rate (as a percent)					1.20%
Debt instrument, facility fee (as a percent)					0.25%
Unsecured revolving credit facility | Subsequent Event
Indebtedness
Unsecured revolving credit facility							$ 165,000,000
Revolving credit facility, available amount							$ 835,000,000
Senior unsecured notes due 2019
Indebtedness
Debt face amount			$ 400,000,000		$ 400,000,000
Interest rate (as a percent)			3.25%		3.25%
Senior unsecured notes due 2020
Indebtedness
Debt face amount			$ 200,000,000		$ 200,000,000
Interest rate (as a percent)			6.75%		6.75%
Senior unsecured notes due 2021
Indebtedness
Debt face amount			$ 300,000,000		$ 300,000,000
Interest rate (as a percent)			6.75%		6.75%
Senior unsecured notes due 2024
Indebtedness
Debt face amount			$ 250,000,000		$ 250,000,000
Interest rate (as a percent)			4.75%		4.75%
Senior unsecured notes due 2028
Indebtedness
Debt face amount			$ 500,000,000		$ 500,000,000
Interest rate (as a percent)		4.75%	4.75%		4.75%
Proceeds from issuance of debt		$ 500,000,000
Proceeds from debt, net of issuance costs		$ 487,264,000
Senior unsecured notes due 2042
Indebtedness
Debt face amount			$ 350,000,000		$ 350,000,000
Interest rate (as a percent)			5.625%		5.625%
Senior unsecured notes due 2046
Indebtedness
Debt face amount			$ 250,000,000		$ 250,000,000
Interest rate (as a percent)			6.25%		6.25%
Term loan due 2020
Indebtedness
Debt face amount			$ 350,000,000		$ 350,000,000
Interest rate (as a percent)			3.50375%		3.50375%
Weighted average interest rate on debt (as a percent)			3.50%	2.60%	3.30%	2.40%
Interest expense and other associated costs incurred			$ 3,263,000	$ 2,491,000	$ 9,106,000	$ 6,802,000
Maximum borrowing capacity that may be increased (up to)			700,000,000		$ 700,000,000
Term loan due 2020 | LIBOR
Indebtedness
Interest rate added to the base rate (as a percent)					1.40%
Term loan due 2022
Indebtedness
Debt face amount			$ 200,000,000		$ 200,000,000
Interest rate (as a percent)			3.60%		3.60%
Weighted average interest rate on debt (as a percent)			3.50%	2.70%	3.30%	2.70%
Interest expense and other associated costs incurred			$ 1,842,000	$ 1,476,000	$ 5,144,000	$ 4,323,000
Maximum borrowing capacity that may be increased (up to)			400,000,000		$ 400,000,000
Term loan due 2022 | LIBOR
Indebtedness
Interest rate added to the base rate (as a percent)					1.35%
Mortgages
Indebtedness
Aggregate principal amount of mortgage debt			$ 735,605,000		$ 735,605,000
Number of properties mortgaged | property			13		13
Number of buildings mortgaged | building			14		14
Total real estate properties, gross			$ 1,033,303,000		$ 1,033,303,000
Capital leases
Indebtedness
Total real estate properties, gross			$ 36,257,000		$ 36,257,000
Number of properties recorded under capital lease | property			2		2
Capital leases			$ 10,053,000		$ 10,053,000
Mortgage loan due 2043
Indebtedness
Interest rate (as a percent)								4.38%
Aggregate principal amount of mortgage debt								$ 4,338,000
Senior unsecured notes due 2018
Indebtedness
Debt face amount	$ 90,602,000
Number of properties mortgaged | property	12
Weighted average interest rate on debt (as a percent)	5.00%
Senior unsecured notes due 2019
Indebtedness
Debt face amount	$ 6,325,000
Interest rate (as a percent)	4.69%

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Recurring Fair Value Measurements
Unrealized gains and losses on equity securities, net	$ 35,137	$ 0	$ 85,643	$ 0
Impairment of assets	$ 4,525	$ 0	$ 5,073	5,082
Five Star
Recurring Fair Value Measurements
Equity securities investment (in shares)	4,235,000		4,235,000
Recurring | RMR Inc
Recurring Fair Value Measurements
Investments in affiliates, fair value	$ 244,751		$ 244,751
Recurring | Five Star
Recurring Fair Value Measurements
Investments in affiliates, fair value	3,643		3,643
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | RMR Inc
Recurring Fair Value Measurements
Investments in affiliates, fair value	244,751		244,751
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Five Star
Recurring Fair Value Measurements
Investments in affiliates, fair value	3,643		3,643
Recurring | Significant Other Observable Inputs (Level 2) | RMR Inc
Recurring Fair Value Measurements
Investments in affiliates, fair value	0		0
Recurring | Significant Other Observable Inputs (Level 2) | Five Star
Recurring Fair Value Measurements
Investments in affiliates, fair value	0		0
Recurring | Significant Unobservable Inputs (Level 3) | RMR Inc
Recurring Fair Value Measurements
Investments in affiliates, fair value	0		0
Recurring | Significant Unobservable Inputs (Level 3) | Five Star
Recurring Fair Value Measurements
Investments in affiliates, fair value	$ 0		$ 0
Class A common shares | RMR Inc
Recurring Fair Value Measurements
Equity securities investment (in shares)	2,637,408		2,637,408
Investment, original cost	$ 69,826		$ 69,826
Unrealized gains and losses on equity securities, net	$ 37,847		$ 88,353
Common Shares | Five Star
Recurring Fair Value Measurements
Equity securities investment (in shares)	4,235,000		4,235,000
Investment, original cost	$ 6,353		$ 6,353
Unrealized gains and losses on equity securities, net	$ (2,710)		$ (2,710)
Impairment of assets				$ 5,082

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Liabilities (Details) $ in Thousands	Sep. 30, 2018USD ($)debt_security	Dec. 31, 2017USD ($)
Liabilities:
Senior unsecured notes	$ 2,215,900	$ 1,725,662
Carrying Amount
Liabilities:
Senior unsecured notes	2,215,900	1,725,662
Secured debt	745,269	805,404
Debt instrument	2,961,169	2,531,066
Estimated Fair Value
Liabilities:
Senior unsecured notes	2,256,958	1,810,882
Secured debt	692,075	794,047
Debt instrument	$ 2,949,033	$ 2,604,929
Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Fair value measurement, number of debt securities | debt_security	2
Significant Other Observable Inputs (Level 2)
Liabilities:
Fair value measurement, number of debt securities | debt_security	5

Noncontrolling Interest (Detail

Noncontrolling Interest (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2017USD ($)buildingproperty	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Noncontrolling Interest [Line Items]
Number of properties included in joint venture agreement | property	1
Number of buildings included in joint venture agreement | building	2
Proceeds from noncontrolling interest, net	$ 255,931			$ 0	$ 255,813
Noncontrolling interest in variable interest equity	181,859
Adjustments to additional paid in capital, difference between net proceeds received and fair value of noncontrolling interest equity	74,072
Comprehensive income attributable to noncontrolling interest		$ (1,397)	$ (1,379)	(4,181)	(2,865)
Cash distribution for joint venture partners		5,151	$ 5,105	15,932	$ 8,587
Variable interest entity, consolidated, carrying amount, real estate assets		749,830		749,830
Variable interest entity, consolidated, carrying amount, mortgage debt		$ 620,000		$ 620,000
Third Party Investor
Noncontrolling Interest [Line Items]
Noncontrolling interest, increase from business combination	$ 261,009
Joint Venture
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by noncontrolling owners	45.00%
Noncontrolling interest, ownership percentage by parent	55.00%

Shareholders' Equity - Compensa

Shareholders' Equity - Compensation (Details) - $ / shares	Oct. 02, 2018	Sep. 24, 2018	Sep. 13, 2018	May 22, 2018	Mar. 29, 2018	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 29, 2017
Employees Of RMR LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares issued in period (in shares)			105,800				105,800	88,100
Shares purchased to satisfy tax withholding and payment obligations, price per share (in dollars per share)		$ 17.56	$ 19.11
Shares purchased to satisfy tax withholding and payment obligations (in shares)		18,121					18,121	16,654
Former Employees Of RMR LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased to satisfy tax withholding and payment obligations, price per share (in dollars per share)									$ 19.15
Shares purchased to satisfy tax withholding and payment obligations (in shares)						4,628
Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares issued in period (in shares)				3,000	3,000
Share-based compensation, equity instruments other than options, nonvested closing price (in dollars per share)					$ 15.66
Shares purchased to satisfy tax withholding and payment obligations, price per share (in dollars per share)				$ 16.56
Subsequent Event | Employees Of RMR LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased to satisfy tax withholding and payment obligations, price per share (in dollars per share)	$ 17.05
Shares purchased to satisfy tax withholding and payment obligations (in shares)	250

Shareholder's Equity - Distribu

Shareholder's Equity - Distribution to Common Shareholders (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 18, 2018	Aug. 16, 2018	Jul. 19, 2018	May 17, 2018	Apr. 19, 2018	Feb. 22, 2018	Jan. 19, 2018	Sep. 30, 2018	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Dividends paid (in dollars per share)		$ 0.39		$ 0.39		$ 0.39
Distributions to shareholders		$ 92,681		$ 92,676		$ 92,674		$ 278,031	$ 277,932
Subsequent Event [Line Items]
Distributions to common shareholders declared (in dollars per share)			$ 0.39		$ 0.39		$ 0.39
Distribution payable			$ 92,681		$ 92,676		$ 92,674
Subsequent Event
Subsequent Event [Line Items]
Distributions to common shareholders declared (in dollars per share)	$ 0.39
Distribution payable	$ 92,715

Segment Reporting (Details)

Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)segment	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			4
Number of reportable segments | segment			3
Revenues:
Total revenues	$ 278,969	$ 266,673	$ 831,942	$ 796,185
Expenses:
Property operating expenses	115,987	104,689	334,141	308,650
Depreciation and amortization	71,661	66,619	214,300	209,463
General and administrative	31,032	19,883	85,228	57,880
Acquisition and certain other transaction related costs	51	19	138	148
Impairment of assets	4,525	0	5,073	5,082
Total expenses	223,256	191,210	638,880	581,223
Gain on sale of properties	0	0	261,916	0
Dividend income	660	659	1,978	1,978
Unrealized gains and losses on equity securities, net	35,137	0	85,643	0
Interest and other income	248	128	362	323
Interest expense	(45,416)	(40,105)	(133,781)	(124,394)
Gain (loss) on early extinguishment of debt	108	(274)	(22)	(7,627)
Income (loss) from continuing operations before income tax expense and equity in earnings of an investee	46,450	35,871	409,158	85,242
Income tax expense	(79)	(109)	(444)	(300)
Equity in earnings of an investee	831	31	882	533
Net income (loss)	47,202	35,793	409,596	85,475
Net income attributable to noncontrolling interest	(1,397)	(1,379)	(4,181)	(2,865)
Net income (loss) attributable to common shareholders	45,805	34,414	405,415	82,610
Assets	7,453,444		7,453,444		$ 7,294,019
MOBs
Revenues:
Total revenues	104,492	96,116	309,497	285,413
Expenses:
Property operating expenses	32,652	29,158	94,773	83,980
Depreciation and amortization	35,223	32,351	105,934	95,890
General and administrative	0	0	0	0
Acquisition and certain other transaction related costs	0	0	0	0
Impairment of assets	0		0	0
Total expenses	67,875	61,509	200,707	179,870
Gain on sale of properties			0
Dividend income	0	0	0	0
Unrealized gains and losses on equity securities, net	0		0
Interest and other income	0	0	0	0
Interest expense	(6,172)	(6,172)	(18,194)	(18,742)
Gain (loss) on early extinguishment of debt	0	0	0	(59)
Income (loss) from continuing operations before income tax expense and equity in earnings of an investee	30,445	28,435	90,596	86,742
Income tax expense	0	0	0	0
Equity in earnings of an investee	0	0	0	0
Net income (loss)	30,445	28,435	90,596	86,742
Net income attributable to noncontrolling interest	(1,397)	(1,379)	(4,181)	(2,865)
Net income (loss) attributable to common shareholders	29,048	27,056	86,415	83,877
Assets	3,408,381		3,408,381		3,367,485
Triple Net Leased Senior Living Communities
Revenues:
Total revenues	64,538	67,662	198,626	202,340
Expenses:
Property operating expenses	0	0	0	0
Depreciation and amortization	20,148	20,629	60,529	61,434
General and administrative	0	0	0	0
Acquisition and certain other transaction related costs	0	0	0	0
Impairment of assets	4,525		5,073	0
Total expenses	24,673	20,629	65,602	61,434
Gain on sale of properties			261,916
Dividend income	0	0	0	0
Unrealized gains and losses on equity securities, net	0		0
Interest and other income	0	0	0	0
Interest expense	(327)	(655)	(1,463)	(8,205)
Gain (loss) on early extinguishment of debt	76	0	76	(7,294)
Income (loss) from continuing operations before income tax expense and equity in earnings of an investee	39,614	46,378	393,553	125,407
Income tax expense	0	0	0	0
Equity in earnings of an investee	0	0	0	0
Net income (loss)	39,614	46,378	393,553	125,407
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to common shareholders	39,614	46,378	393,553	125,407
Assets	2,121,134		2,121,134		2,251,756
Managed Senior Living Communities
Revenues:
Total revenues	105,321	98,325	309,981	294,748
Expenses:
Property operating expenses	83,335	75,531	239,368	224,670
Depreciation and amortization	15,341	12,691	44,993	49,295
General and administrative	0	0	0	0
Acquisition and certain other transaction related costs	0	0	0	0
Impairment of assets	0		0	0
Total expenses	98,676	88,222	284,361	273,965
Gain on sale of properties			0
Dividend income	0	0	0	0
Unrealized gains and losses on equity securities, net	0		0
Interest and other income	0	0	0	0
Interest expense	(997)	(1,172)	(3,580)	(3,523)
Gain (loss) on early extinguishment of debt	32	0	(98)	0
Income (loss) from continuing operations before income tax expense and equity in earnings of an investee	5,680	8,931	21,942	17,260
Income tax expense	0	0	0	0
Equity in earnings of an investee	0	0	0	0
Net income (loss)	5,680	8,931	21,942	17,260
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to common shareholders	5,680	8,931	21,942	17,260
Assets	1,351,382		1,351,382		1,273,757
All Other Operations
Revenues:
Total revenues	4,618	4,570	13,838	13,684
Expenses:
Property operating expenses	0	0	0	0
Depreciation and amortization	949	948	2,844	2,844
General and administrative	31,032	19,883	85,228	57,880
Acquisition and certain other transaction related costs	51	19	138	148
Impairment of assets	0		0	5,082
Total expenses	32,032	20,850	88,210	65,954
Gain on sale of properties			0
Dividend income	660	659	1,978	1,978
Unrealized gains and losses on equity securities, net	35,137		85,643
Interest and other income	248	128	362	323
Interest expense	(37,920)	(32,106)	(110,544)	(93,924)
Gain (loss) on early extinguishment of debt	0	(274)	0	(274)
Income (loss) from continuing operations before income tax expense and equity in earnings of an investee	(29,289)	(47,873)	(96,933)	(144,167)
Income tax expense	(79)	(109)	(444)	(300)
Equity in earnings of an investee	831	31	882	533
Net income (loss)	(28,537)	(47,951)	(96,495)	(143,934)
Net income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to common shareholders	(28,537)	(47,951)	(96,495)	(143,934)
Assets	572,547		572,547		$ 401,021
Rental income
Revenues:
Total revenues	173,648	168,348	521,961	501,437
Rental income | MOBs
Revenues:
Total revenues	104,492	96,116	309,497	285,413
Rental income | Triple Net Leased Senior Living Communities
Revenues:
Total revenues	64,538	67,662	198,626	202,340
Rental income | Managed Senior Living Communities
Revenues:
Total revenues	0	0	0	0
Rental income | All Other Operations
Revenues:
Total revenues	4,618	4,570	13,838	13,684
Residents fees and services
Revenues:
Total revenues	105,321	98,325	309,981	294,748
Residents fees and services | MOBs
Revenues:
Total revenues	0	0	0	0
Residents fees and services | Triple Net Leased Senior Living Communities
Revenues:
Total revenues	0	0	0	0
Residents fees and services | Managed Senior Living Communities
Revenues:
Total revenues	105,321	98,325	309,981	294,748
Residents fees and services | All Other Operations
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0

Leases and Management Agreeme_2

Leases and Management Agreements with Five Star (Details) - Five Star $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)living_unitcommunity	Sep. 30, 2017USD ($)community	Sep. 30, 2018USD ($)living_unitcommunitylease_agreement	Sep. 30, 2017USD ($)community	Nov. 30, 2018living_unit	Dec. 31, 2017USD ($)
Number of communities leased by the Company | community	184	185	184	185
Number of leases with related party | lease_agreement			5
Total rental income recognized	$ 51,757	$ 51,333	$ 155,207	$ 153,441
Related party transaction, annual rents due	1,386	1,353	4,050	4,190
Rents receivable	$ 17,256		17,256			$ 18,539
Real estate improvements purchased			14,749	30,698
Increase or decrease in annual lease rent payable			$ 1,177	2,464
Number of communities owned and managed by related party | living_unit	98		98
Property management agreement expense	$ 3,666	3,414	$ 10,694	$ 10,531
Rents from significant lessee | Revenues
Percentage of rental income	18.60%		18.70%
Rents from significant lessee | Investment
Percentage of rental income			27.00%
Senior Living Communities
Number of communities managed by related party | community			75	68
Rehabilitation Services
Expenses from transactions with related party	$ 1,584	$ 1,841	$ 4,944	$ 5,709
Subsequent Event
Number of communities owned and managed by related party | living_unit					238

Business and Property Managem_2

Business and Property Management Agreements with RMR LLC (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2018USD ($)	Sep. 30, 2018USD ($)employee	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)propertyemployeemanagement_agreement	Sep. 30, 2017USD ($)
Related person transactions
Number of employees | employee		0		0
Related party transaction business management agreement incentive fee paid	$ 55,740
Property management and construction supervision fees		$ 3,025	$ 2,736	$ 8,829	$ 8,034
Property management and construction supervision fees paid		3,440	2,353	9,391	7,116
Professional fees		35	72	173	206
RMR LLC
Related person transactions
Business management fees incurred		28,306	17,744	78,119	50,956
Related party transaction business management fees related to subsidiary level management		725	725	2,175	1,512
Related party transaction business management agreement, annual incentive fee estimate included in management fees		$ 18,751	$ 8,022	$ 50,708	$ 22,048
Related party transaction, incentive fee payable assessment period				3 years
Senior Living Communities | RMR Inc
Related person transactions
Number of consecutive renewal terms of agreement | management_agreement				2
Number of communities managed by related party | property				1

Related Person Transactions (De

Related Person Transactions (Details) $ in Thousands	Sep. 24, 2018shares	Sep. 13, 2018shares	Sep. 30, 2018USD ($)agreementshares	Sep. 30, 2017shares	Mar. 31, 2017building	Sep. 30, 2018USD ($)buildingagreementshares	Dec. 31, 2017USD ($)
Related person transactions
Number of buildings included in joint venture agreement | building					2
RMR Inc | Class A common shares
Related person transactions
Equity securities investment (in shares)			2,637,408			2,637,408
Number of management agreements | agreement			2			2
Five Star
Related person transactions
Equity securities investment (in shares)			4,235,000			4,235,000
Investment owned, percentage of total shares outstanding			8.40%			8.40%
Employees Of RMR LLC
Related person transactions
Shares issued in period (in shares)		105,800	105,800	88,100
Shares purchased to satisfy tax withholding and payment obligations (in shares)	18,121		18,121	16,654
AIC
Related person transactions
Property insurance annual premium | $						$ 4,413
Equity method investments | $			$ 9,157			$ 9,157	$ 8,185
RMR LLC | Five Star
Related person transactions
Investment owned, percentage of total shares outstanding			35.60%			35.60%
MOBs
Related person transactions
Standalone insurance policy coverage period						1 year
Number of buildings included in joint venture agreement | building						2

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income tax expense	$ (79)	$ (109)	$ (444)	$ (300)

Weighted Average Common Share_2

Weighted Average Common Shares (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Weighted average common shares for basic earnings per share (in shares)	237,511	237,421	237,492	237,404
Effect of dilutive securities: unvested share awards (in shares)	51	39	34	41
Weighted average common shares for diluted earnings per share (in shares)	237,562	237,460	237,526	237,445