Segment Reporting (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net revenues		$ 2,541,864	$ 2,409,872	$ 7,767,078	$ 7,290,525
Total assets		10,639,360	9,673,639	10,639,360	9,673,639	$ 10,317,802
Behavioral Health Services
Segment Reporting Information [Line Items]
Net revenues	[1]	1,224,548	1,153,880	3,685,230	3,489,681
Total assets	[1]	6,610,811	5,927,564	6,610,811	5,927,564
Behavioral Health Services | Located in U.K.
Segment Reporting Information [Line Items]
Net revenues		111,000	60,000	317,000	185,000
Total assets		$ 1,094,000	$ 485,000	$ 1,094,000	$ 485,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $111 million and $60 million for the three-month periods ended September 30, 2017 and 2016, respectively, and approximately $317 million and $185 million for the nine-month periods ended September 30, 2017 and 2016, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.094 billion and $485 million as of September 30, 2017 and 2016, respectively.