Commitments and Contingencies (Schedule of Lease Commitments) (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Maximum Commitment For All Active Development Projects	$ 31,295
Development in Process	(21,646)
Remaining Unfunded Development Commitment	9,649
Capital Improvement Commitment [Member]
Maximum Commitment For All Active Development Projects	2,800
Development in Process	(391)
Remaining Unfunded Development Commitment	2,409
Capital Improvement Commitment [Member] | Woodland Village [Member]
Maximum Commitment For All Active Development Projects	7,515
Development in Process	(7,425)
Remaining Unfunded Development Commitment	90
Capital Improvement Commitment [Member] | Senior Living Communities [Member]
Maximum Commitment For All Active Development Projects	9,930
Development in Process	(9,930)
Remaining Unfunded Development Commitment	0
Capital Improvement Commitment [Member] | Discovery Senior Living [Member]
Maximum Commitment For All Active Development Projects	900
Development in Process	(900)
Remaining Unfunded Development Commitment	0
Capital Improvement Commitment [Member] | Watermark Retirement [Member]
Maximum Commitment For All Active Development Projects	6,500
Development in Process	(3,000)
Remaining Unfunded Development Commitment	3,500
Capital Improvement Commitment [Member] | Navion Senior Solutions [Member]
Maximum Commitment For All Active Development Projects	3,650
Development in Process	0
Remaining Unfunded Development Commitment	$ 3,650