Real Estate and Other Activities - Investments in Unconsolidated Operating Entities - Additional Information (Details) £ in Millions, SFr in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2024 GBP (£)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 CHF (SFr)
Swiss Medical Network [Member]
Business Acquisition [Line Items]
Favorable fair market value adjustment on investment | SFr					SFr 20
PHP Holdings Equity Investment [Member]
Business Acquisition [Line Items]
Favorable fair market value adjustment on investment				$ 45.0
Syndicated Term Loan [Member]
Business Acquisition [Line Items]
Proceed from sale of interest in syndicated term loan	$ 115.0	£ 90
Gain (loss) on sale of interest in syndicated term loan	(7.8)	£ (6)
Other [Member]
Business Acquisition [Line Items]
Unfavorable fair market value adjustment on investment	$ 225.0		$ 550.0
COVID-19 Pandemic [Member] | Other [Member]
Business Acquisition [Line Items]
Favorable non-cash fair value adjustment on investment				$ 45.0
Unfavorable non-cash fair value adjustment on investment			$ 794.0