Summary of Changes in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 3,596,114	$ 3,291,213
Goodwill acquired during the period		234,658	318,907
Goodwill divested during the period			(1,497)
Adjustments to goodwill	[1]	(46,666)	(12,509)
Goodwill, Ending Balance		3,784,106	3,596,114
Acute Care Services
Goodwill [Line Items]
Goodwill, Beginning Balance		389,507	387,099
Goodwill acquired during the period		50,897	2,480
Goodwill divested during the period			0
Adjustments to goodwill	[1]	(110)	(72)
Goodwill, Ending Balance		440,294	389,507
Behavioral Health Services
Goodwill [Line Items]
Goodwill, Beginning Balance		3,206,607	2,904,114
Goodwill acquired during the period		183,761	316,427
Goodwill divested during the period			(1,497)
Adjustments to goodwill	[1]	(46,556)	(12,437)
Goodwill, Ending Balance		$ 3,343,812	$ 3,206,607

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