Segment Reporting (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Gross inpatient revenues	$ 4,863,920	$ 4,423,652	$ 14,866,875	$ 13,568,872
Gross outpatient revenues	1,902,280	1,683,524	5,663,033	5,120,771
Total net revenues	1,816,369	1,680,353	5,482,976	5,196,473
Income/(loss) before allocation of corporate overhead and income taxes	192,572	123,505	662,374	530,267
Allocation of corporate overhead	0	0	0	0
Income/(loss) after allocation of corporate overhead and before income taxes	192,572	123,505	662,374	530,267
Total assets	8,351,743	7,781,066	8,351,743	7,781,066	8,200,843
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	3,296,484	3,013,482	10,124,908	9,326,344
Gross outpatient revenues	1,712,290	1,517,261	5,072,065	4,606,680
Total net revenues	899,533	828,399	2,702,913	2,598,527
Income/(loss) before allocation of corporate overhead and income taxes	68,266	51,591	267,285	245,718
Allocation of corporate overhead	(46,112)	(39,360)	(138,333)	(118,082)
Income/(loss) after allocation of corporate overhead and before income taxes	22,154	12,231	128,952	127,636
Total assets	3,123,780	2,925,327	3,123,780	2,925,327
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	1,567,436	1,410,170	4,741,967	4,242,528
Gross outpatient revenues	179,783	151,788	559,288	474,623
Total net revenues	907,935	841,669	2,746,949	2,572,256
Income/(loss) before allocation of corporate overhead and income taxes	211,456	199,275	672,787	623,524
Allocation of corporate overhead	(22,265)	(20,727)	(67,093)	(62,665)
Income/(loss) after allocation of corporate overhead and before income taxes	189,191	178,548	605,694	560,859
Total assets	4,926,271	4,448,775	4,926,271	4,448,775
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues	0	0	0	0
Gross outpatient revenues	10,207	14,475	31,680	39,468
Total net revenues	8,901	10,285	33,114	25,690
Income/(loss) before allocation of corporate overhead and income taxes	(87,150)	(127,361)	(277,698)	(338,975)
Allocation of corporate overhead	68,377	60,087	205,426	180,747
Income/(loss) after allocation of corporate overhead and before income taxes	(18,773)	(67,274)	(72,272)	(158,228)
Total assets	$ 301,692	$ 406,964	$ 301,692	$ 406,964