Significant Accounting Policies (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 3,166,971	$ 3,042,235
Straight-Line Rent Receivable [Member] | Bickford Senior Living [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	74,864
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(60,708)
Straight-Line Rent Receivable [Member] | Senior Living Communities [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	97,404
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(93,401)
Straight-Line Rent Receivable [Member] | Senior Living Management [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	26,969
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(26,969)
Notes Receivable [Member] | Evolve Senior Living [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	9,958
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(9,958)
Notes Receivable [Member] | LCS Sagewood [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	178,697
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(142,586)
Notes Receivable [Member] | 41 Management [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	15,315
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(12,868)
Notes Receivable [Member] | Timber Ridge OpCo
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	4,586
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	(414)
Notes Receivable [Member] | Watermark Retirement [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	8,628
Variable Interest Entity, Reporting Entity Involvement, Carrying Amount	$ (3,628)