Real Property Acquisitions and Development (Purchase Price Calculation and Allocation to Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jul. 26, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Real property held for sale	$ 590,271		$ 734,147
Cash and cash equivalents	215,376		243,777
Restricted cash	$ 100,753		$ 65,526
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