Segment Reporting (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Gross inpatient revenues	$ 5,410,821	$ 4,919,537	$ 10,896,084	$ 10,002,955
Gross outpatient revenues	2,280,891	1,912,528	4,431,011	3,760,753
Total net revenues	2,019,821	1,834,975	3,939,987	3,666,607
Income/(loss) before allocation of corporate overhead and income taxes	258,345	265,818	494,128	469,802
Allocation of corporate overhead	0	0	0	0
Income/(loss) after allocation of corporate overhead and before income taxes	258,345	265,818	494,128	469,802
Total assets	8,548,072	8,317,253	8,548,072	8,317,253	8,311,723
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	3,724,309	3,321,154	7,600,673	6,828,424
Gross outpatient revenues	2,068,076	1,708,200	4,025,567	3,359,775
Total net revenues	1,024,011	894,639	1,995,400	1,803,373
Income/(loss) before allocation of corporate overhead and income taxes	118,345	118,390	229,994	199,019
Allocation of corporate overhead	(44,693)	(46,109)	(89,390)	(92,221)
Income/(loss) after allocation of corporate overhead and before income taxes	73,652	72,281	140,604	106,798
Total assets	3,319,048	3,126,223	3,319,048	3,126,223
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	1,686,512	1,598,383	3,295,411	3,174,531
Gross outpatient revenues	204,480	193,703	388,595	379,505
Total net revenues	992,348	929,470	1,937,805	1,839,014
Income/(loss) before allocation of corporate overhead and income taxes	243,540	240,556	464,688	461,331
Allocation of corporate overhead	(23,136)	(22,461)	(49,305)	(44,828)
Income/(loss) after allocation of corporate overhead and before income taxes	220,404	218,095	415,383	416,503
Total assets	4,995,534	4,919,566	4,995,534	4,919,566
Other
Segment Reporting Information [Line Items]
Gross outpatient revenues	8,335	10,625	16,849	21,473
Total net revenues	3,462	10,866	6,782	24,220
Income/(loss) before allocation of corporate overhead and income taxes	(103,540)	(93,128)	(200,554)	(190,548)
Allocation of corporate overhead	67,829	68,570	138,695	137,049
Income/(loss) after allocation of corporate overhead and before income taxes	(35,711)	(24,558)	(61,859)	(53,499)
Total assets	$ 233,490	$ 271,464	$ 233,490	$ 271,464