Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net revenues		$ 2,687,516	$ 2,612,858
Total assets		11,023,517	10,448,259	$ 10,761,828
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	[1]	1,237,996	1,218,122
Total assets	[1]	6,649,732	6,517,608
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues		115,000	100,000
Total assets		$ 1,176,000	$ 992,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $115 million and $100 million for the three-month periods ended March 31, 2018 and 2017, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.176 billion and $992 million as of March 31, 2018 and 2017, respectively.