Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net revenues		$ 3,012,987	$ 2,829,667
Total assets		13,096,329	11,620,426	$ 13,476,879
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	[1]	1,315,337	1,306,109
Total assets	[1]	7,090,291	6,871,852
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues		165,000	137,000
Total assets		$ 1,355,000	$ 1,197,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $165 million and $137 million for the three-month periods ended March 31, 2021 and 2020, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.355 billion and $1.197 billion as of March 31, 2021 and 2020, respectively.