Leases and Management Agreements with Five Star - Narrative (Details) $ in Thousands		1 Months Ended	3 Months Ended								12 Months Ended
	Apr. 01, 2019 USD ($)	Dec. 31, 2019 USD ($) living_unit community shares	Dec. 31, 2019 USD ($) community shares	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) community shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) living_unit community lease_agreement renewal_option shares	Dec. 31, 2018 USD ($) community shares	Dec. 31, 2017 USD ($) community	Jan. 01, 2020	Feb. 01, 2019 USD ($)
Concentration Risk [Line Items]
Common shares, shares issued (in shares) | shares		237,897,163	237,897,163				237,729,900				237,897,163	237,729,900
Unsecured revolving credit facility		$ 537,500	$ 537,500				$ 139,000				$ 537,500	$ 139,000
Total revenues			$ 256,039	$ 255,827	$ 262,003	$ 266,286	$ 285,222	$ 278,969	$ 277,202	$ 275,770	$ 1,040,155	1,117,164	$ 1,074,729
Subsequent Event | Five Star
Concentration Risk [Line Items]
Equity method investment ownership percentage														33.90%
Five Star
Concentration Risk [Line Items]
Common shares, shares issued (in shares) | shares		10,268,158	10,268,158								10,268,158
Five Star
Concentration Risk [Line Items]
Amounts of transaction											$ 75,000
Monthly minimum rent payable															$ 11,000
Management fees as a percentage of gross revenues		5.00%	5.00%								5.00%
Percentage of annual incentive fee		15.00%	15.00%								15.00%
Property management agreement, management fees		1.50%	1.50%								1.50%
Business and property management agreement, number of agreements | renewal_option											2
Percentage target EBITDA of new management agreement not earned											90.00%
Percentage target EBITDA of new management agreement not earned for all communities											20.00%
Unsecured revolving credit facility		$ 25,000	$ 25,000								$ 25,000
Increase in annual lease rent payable												1,433
Amount of improvements to communities											111,603
Payments to acquire property, plant, and equipment											49,155
Senior Living Communities
Concentration Risk [Line Items]
Real estate improvements by lessee purchased											1,739	5,420
Increase in annual lease rent payable											$ 90	$ 383
Number of living units | living_unit											31,618
Five Star
Concentration Risk [Line Items]
Number of communities leased by the company | community		166	166				184				166	184	185
Rents receivable		$ 1,989	$ 1,989				$ 18,697				$ 1,989	$ 18,697	$ 18,539
Real estate improvements by lessee purchased												17,956	39,800
Increase in annual lease rent payable												1,433	3,193
Expenses from property management agreement transactions with related party											$ 15,327	14,426	14,080
Five Star | Senior Living Communities
Concentration Risk [Line Items]
Number of communities managed | community											78
Expenses from property management agreement transactions with related party											$ 5,920	6,442	7,525
Shareholders | Five Star
Concentration Risk [Line Items]
Common shares, shares issued (in shares) | shares		16,118,849	16,118,849								16,118,849
Plano, Texas
Concentration Risk [Line Items]
Number of living units | living_unit		169
Purchase price, including closing costs		$ 50,300
Five Star
Concentration Risk [Line Items]
Number of leases with related party | lease_agreement											5
Annual rent as a percentage of gross revenues, percent		4.00%	4.00%								4.00%
Annual rent as a percentage of gross revenues, amount											$ 538	$ 5,525	$ 5,533
Five Star | Senior Living Communities
Concentration Risk [Line Items]
Number of communities managed | community											78	76	70
Five Star | Lease No. 1
Concentration Risk [Line Items]
Number of communities | community											73
Five Star | Lease No. 2
Concentration Risk [Line Items]
Number of communities | community											39
Five Star | Lease No. 3
Concentration Risk [Line Items]
Number of communities | community											17
Five Star | Lease No. 4
Concentration Risk [Line Items]
Number of communities | community											28
Five Star | Lease No. 5
Concentration Risk [Line Items]
Number of communities | community											9
Five Star | Senior Living Communities
Concentration Risk [Line Items]
Payments to acquire property, plant, and equipment	$ 49,155
SHOP
Concentration Risk [Line Items]
Total revenues											$ 571,495	$ 629,145	$ 604,246
Rental income
Concentration Risk [Line Items]
Total revenues											606,558	700,641	681,022
Rental income | SHOP
Concentration Risk [Line Items]
Total revenues											137,898	212,622	210,539
Rental income | SHOP | Five Star
Concentration Risk [Line Items]
Total revenues											$ 137,898	$ 212,622	$ 210,539