Segment Reporting (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Gross inpatient revenues	$ 5,294,869	$ 4,863,920	$ 16,190,953	$ 14,866,875
Gross outpatient revenues	2,259,152	1,902,280	6,690,163	5,663,033
Total net revenues	2,017,758	1,816,369	5,957,745	5,482,976
Income/(loss) before allocation of corporate overhead and income taxes	144,478	192,572	638,606	662,374
Allocation of corporate overhead	0	0	0	0
Income/(loss) after allocation of corporate overhead and before income taxes	144,478	192,572	638,606	662,374
Total assets	8,961,592	8,351,743	8,961,592	8,351,743	8,311,723
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	3,616,647	3,296,484	11,217,320	10,124,908
Gross outpatient revenues	2,058,148	1,712,290	6,083,715	5,072,065
Total net revenues	1,038,135	899,533	3,033,535	2,702,913
Income/(loss) before allocation of corporate overhead and income taxes	100,388	68,266	330,382	267,285
Allocation of corporate overhead	(44,698)	(46,112)	(134,088)	(138,333)
Income/(loss) after allocation of corporate overhead and before income taxes	55,690	22,154	196,294	128,952
Total assets	3,321,166	3,123,780	3,321,166	3,123,780
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	1,678,222	1,567,436	4,973,633	4,741,967
Gross outpatient revenues	192,032	179,783	580,627	559,288
Total net revenues	976,014	907,935	2,913,819	2,746,949
Income/(loss) before allocation of corporate overhead and income taxes	228,710	211,456	693,399	672,787
Allocation of corporate overhead	(24,750)	(22,265)	(74,055)	(67,093)
Income/(loss) after allocation of corporate overhead and before income taxes	203,960	189,191	619,344	605,694
Total assets	5,429,453	4,926,271	5,429,453	4,926,271
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues	0	0	0	0
Gross outpatient revenues	8,972	10,207	25,821	31,680
Total net revenues	3,609	8,901	10,391	33,114
Income/(loss) before allocation of corporate overhead and income taxes	(184,620)	(87,150)	(385,175)	(277,698)
Allocation of corporate overhead	69,448	68,377	208,143	205,426
Income/(loss) after allocation of corporate overhead and before income taxes	(115,172)	(18,773)	(177,032)	(72,272)
Total assets	$ 210,973	$ 301,692	$ 210,973	$ 301,692