Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) facility loan	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) facility segment loan	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Accounting Policies [Abstract]
Accumulated amortization of deferred financing costs	$ 4,100		$ 4,100		$ 3,200
Straight-line rental income	300	$ 42	933	$ 115
Deferred straight-line rent receivable	$ 1,400		$ 1,400		500
Number of reportable segments | segment			1
Other Commitments [Line Items]
Number of loans to be funded | loan	2		2
Number of living facilities | facility	191		191
Unpaid Base Rents
Other Commitments [Line Items]
Reserve on receivables	$ 1,500		$ 1,500		800
Other Tenant Receivables
Other Commitments [Line Items]
Reserve on receivables	11,200		11,200		9,600
Lease Agreements
Other Commitments [Line Items]
Remaining contractual payments as lessee	$ 200		$ 200
Independent Living Facilities Owned and Operated by Company
Other Commitments [Line Items]
Number of living facilities | facility	3		3
Bridge Loan
Other Commitments [Line Items]
Loans receivable	$ 1,400		$ 1,400
Maximum | Eduro Healthcare LLC Loan | Bridge Loan
Other Commitments [Line Items]
Funding commitment	4,000		4,000
Maximum | Providence Group Loan | Bridge Loan
Other Commitments [Line Items]
Funding commitment	4,000		4,000
Pristine Senior Living LLC
Other Commitments [Line Items]
Reserve on receivables	$ 10,400		$ 10,400		$ 10,400