Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 3,291,213	$ 3,049,016
Goodwill acquired during the period		318,907	250,212
Goodwill divested during the period		(1,497)
Adjustments to goodwill	[1]	(12,509)	(8,015)
Goodwill, Ending Balance		3,596,114	3,291,213
Acute Care Services
Goodwill [Line Items]
Goodwill, Beginning Balance		387,099	383,011
Goodwill acquired during the period		2,480	4,088
Goodwill divested during the period		0
Adjustments to goodwill	[1]	(72)	0
Goodwill, Ending Balance		389,507	387,099
Behavioral Health Services
Goodwill [Line Items]
Goodwill, Beginning Balance		2,904,114	2,666,005
Goodwill acquired during the period		316,427	246,124
Goodwill divested during the period		(1,497)
Adjustments to goodwill	[1]	(12,437)	(8,015)
Goodwill, Ending Balance		$ 3,206,607	$ 2,904,114

[1] The decrease in the Behavioral Health Services’ goodwill consists primarily of foreign currency translation adjustments.