Schedule IV - Changes in Mortgage Loans Excluding Allowance for Credit Loss (Parenthetical) (Detail) $ in Thousands, £ in Millions		Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2021 GBP (£)	Dec. 31, 2020 USD ($)
Mortgage Loans on Real Estate [Line Items]
Advanced to the mortgage loan	[1]		$ 1,103,410		$ 834,743
Mortgage Loans [Member]
Mortgage Loans on Real Estate [Line Items]
Advanced to the mortgage loan		$ 835,000
Mortgage Loans [Member] | Priory Group [Member]
Mortgage Loans on Real Estate [Line Items]
Advanced to the mortgage loan | £				£ 800

[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 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.