Real Property Acquisitions and Development (Schedule of Purchase Price Calculation and Allocation to Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jul. 26, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Land and land improvements	$ 472,500	$ 542,267		$ 116,506
Buildings and improvements	3,676,958	3,343,355		836,879
Acquired lease intangibles	259,930	130,007		87,926
Real property held for sale	1,253,008	590,271
Cash and cash equivalents	284,917	215,376
Restricted cash	100,849	100,753
Receivables and other assets	17,220	4,031		3,969
Total assets acquired	4,538,594	4,437,957		1,045,280
Accrued expenses and other liabilities	(44,917)	(46,558)		(70,718)
Total liabilities assumed	(493,819)	(350,466)		(96,426)
Noncontrolling interests	$ (73,203)	$ (527,131)		$ (21,056)
Quality Care Properties Inc. (QCP)
Business Acquisition [Line Items]
Land and land improvements			$ 417,983
Buildings and improvements			2,253,451
Acquired lease intangibles			12,820
Real property held for sale			418,297
Cash and cash equivalents			381,913
Restricted cash			4,981
Receivables and other assets			1,354
Total assets acquired			3,490,799
Accrued expenses and other liabilities			(13,199)
Total liabilities assumed			(13,199)
Noncontrolling interests			(512,741)
Net assets acquired			$ 2,964,859