Real Estate Investments, Net - Rental Income (Details)	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) operator
Lessor, Lease, Description [Line Items]
Contractual rent due	$ 190,100,000	$ 171,309,000	$ 166,056,000
Straight-line rent	32,000	77,000	1,385,000
Adjustment for collectibility	0	0	(11,774,000)
Recovery of previously reserved rent	0	1,047,000	0
Lease termination revenue	63,000	1,179,000	0
Total	190,195,000	173,612,000	$ 155,667,000
Number of operators for which collectability not probable | operator			5
Contractual rent
Lessor, Lease, Description [Line Items]
Adjustment for collectibility			$ (7,800,000)
Straight-line rent
Lessor, Lease, Description [Line Items]
Adjustment for collectibility			(3,500,000)
Property taxes
Lessor, Lease, Description [Line Items]
Adjustment for collectibility			$ (500,000)
Metron
Lessor, Lease, Description [Line Items]
Recovery of previously reserved rent		1,000,000
Lease termination revenue	$ 100,000	$ 1,200,000