Real Estate Activities - Net Assets Acquired (Parenthetical) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Weighted-average useful life of acquired intangible lease assets (in years)		21 years 3 months 18 days
Loans repaid	[1]	$ 834,743		$ 764,447
Steward [Member]
Business Acquisition [Line Items]
Loans repaid		750,000		$ 800,000
Ernest [Member]
Business Acquisition [Line Items]
Loans repaid		$ 100,000
Intangible Lease Assets - Subject to Amortization [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired intangible lease assets (in years)		27 years 6 months	19 years 1 month 6 days	27 years 10 months 24 days

[1] The 2020 column includes approximately $750 million of loans advanced to Steward in 2017 and exchanged for the fee simple real estate of two hospitals as described below, as well as approximately $100 million of loans advanced to Ernest Health, Inc. (“Ernest”) in 2012 and exchanged for the fee simple real estate of four hospitals as described below. 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.