Real Estate and Other Activities - Net Assets Acquired (Detail) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Total assets acquired		$ 235,187	$ 1,332,962	$ 5,350,239
Liabilities assumed			(25,727)	(82,508)
Loans repaid	[1]	(22,900)		(1,103,410)
Total net assets acquired		212,287	1,332,962	4,246,829
Land and Land Improvements [Member]
Business Acquisition [Line Items]
Total assets acquired		28,916	135,301	642,312
Building [Member]
Business Acquisition [Line Items]
Total assets acquired		114,966	487,698	2,381,654
Intangible Lease Assets [Member]
Business Acquisition [Line Items]
Total assets acquired		16,305	45,394	262,385
Mortgage Loans [Member]
Business Acquisition [Line Items]
Total assets acquired	[1]		159,735	1,113,300
Other Loans [Member]
Business Acquisition [Line Items]
Total assets acquired		25,000
Investments in Unconsolidated Real Estate Joint Ventures [Member]
Business Acquisition [Line Items]
Total assets acquired			399,456
Investments In Unconsolidated Operating Entities [Member]
Business Acquisition [Line Items]
Total assets acquired		$ 50,000	$ 131,105	$ 1,033,096

[1] The 2023 column includes a $23 million mortgage loan that was converted to fee simple ownership of one property as described under the Lifepoint Transaction below. 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.