Leases and Management Agreements with Five Star - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
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
Basic housing and support services
Disaggregation of Revenue [Line Items]
Total revenues									353,699
Medicare and Medicaid programs
Disaggregation of Revenue [Line Items]
Total revenues									31,324
Private pay and other third party payer SNF services
Disaggregation of Revenue [Line Items]
Total revenues									48,574
Residents fees and services
Disaggregation of Revenue [Line Items]
Total revenues									$ 433,597	$ 416,523	$ 393,707