Real Estate and Other Activities - Net Assets Acquired (Parenthetical) (Detail) $ in Thousands, £ in Millions		12 Months Ended
		Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) Hospital	Dec. 31, 2019 USD ($) Hospital	Jun. 30, 2021 Property	Mar. 31, 2021 GBP (£)
Business Acquisition [Line Items]
Weighted-average useful life of acquired intangible lease assets (in years)		22 years 10 months 24 days
Advanced to the mortgage loan	[1]	$ 1,103,410	$ 834,743
Ernest [Member]
Business Acquisition [Line Items]
Number of facilities acquired | Hospital				4
Priory Group [Member]
Business Acquisition [Line Items]
Number of real estate assets acquired | Property					35
Steward Health Care System LLC [Member]
Business Acquisition [Line Items]
Number of facilities acquired | Hospital			2
Mortgage Loans [Member] | Ernest [Member]
Business Acquisition [Line Items]
Advanced to the mortgage loan				$ 100,000
Mortgage Loans [Member] | Priory Group [Member]
Business Acquisition [Line Items]
Advanced to the mortgage loan | £						£ 800
Mortgage Loans [Member] | Steward Health Care System LLC [Member]
Business Acquisition [Line Items]
Advanced to the mortgage loan			$ 740,000
Intangible Lease Assets {Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired intangible lease assets (in years)		34 years 6 months	27 years 6 months	19 years 1 month 6 days

[1] The 2021 column includes an £800 million mortgage loan advanced to the Priory Group (“Priory”) in the first quarter of 2021 and converted to fee simple ownership in a portfolio of 35 properties in the second quarter of 2021 as described below. The 2020 column includes approximately $740 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.