Real Estate and Lending Activities - Net Assets Acquired (Parenthetical) (Detail) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Loans repaid	[1]	$ 737,242
Steward [Member]
Business Acquisition [Line Items]
Loans repaid		$ 737,000
Intangible Lease Assets - Subject to Amortization [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired intangible lease assets (in years)		27 years 7 months 6 days	18 years 8 months 12 days

[1] The 2020 column includes $737 million of loans advanced to Steward Health Care, Inc. (“Steward”) in 2017 and exchanged for the fee simple real estate of two hospitals as described below.