Real Estate Activities - Assets Acquired (Detail) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Total assets acquired		$ 1,430,995	$ 2,246,788	$ 1,682,409
Equity investments and other assets		245,267	100,000	70,166
Liabilities assumed			(878)	(6,319)
Loans repaid	[1]	(764,447)		(193,262)
Total net assets acquired		666,548	2,246,788	1,489,147
Land [Member]
Business Acquisition [Line Items]
Total assets acquired		71,880	240,993	91,071
Building [Member]
Business Acquisition [Line Items]
Total assets acquired		686,739	985,219	655,324
Intangible Lease Assets - Subject to Amortization [Member]
Business Acquisition [Line Items]
Total assets acquired		90,651	181,004	94,167
Net Investments in Direct Financing Leases [Member]
Business Acquisition [Line Items]
Total assets acquired			40,450	178,000
Mortgage Loans [Member]
Business Acquisition [Line Items]
Total assets acquired			$ 700,000	$ 600,000
Other Loans [Member]
Business Acquisition [Line Items]
Total assets acquired		$ 336,458

[1] The 2018 column includes $0.8 billion of loans advanced to Steward in 2016 and repaid in 2018 as part of sale leaseback conversion described below. The 2016 column includes $93.3 million of loans advanced to Capella(2) in 2015 and repaid in 2016 as a part of the Capella transaction (2), along with $100.0 million of loans advanced to Prime Healthcare Services, Inc. (“Prime”) in 2015 and repaid in 2016 as part of the sale leaseback conversion of four properties in New Jersey.