Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Net revenues	$ 4,495,245	$ 3,963,027	$ 12,878,781	$ 11,714,213
Total assets	15,343,924		15,343,924		$ 14,469,749
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	1,860,259	1,706,612	5,487,984	5,088,711
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues	$ 264,000	$ 230,000	$ 738,000	$ 651,000