Variable Interest Entities - Schedule of Variable Interest Entities (Details) $ in Thousands	Dec. 31, 2018 USD ($)
VIE tenants-DFLs
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	$ 600,230
VIE tenants-operating leases
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	7,396
CCRC OpCo
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	176,236
Unconsolidated development joint ventures
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	15,176
Loan - seller financing
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	10,000
CMBS and LLC investment
Variable Interest Entity [Line Items]
Maximum loss exposure and carrying amount	$ 34,263