Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 7,780,852	$ 6,925,107
Gross outpatient revenues		3,540,637	2,988,972
Total net revenues		2,612,858	2,449,798
Income/(loss) before allocation of corporate overhead and income taxes		318,426	326,724
Allocation of corporate overhead		0	0
Income/(loss) after allocation of corporate overhead and before income taxes		318,426	326,724
Total assets		10,448,259	9,565,009	$ 10,317,802
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		5,597,850	4,965,537
Gross outpatient revenues		3,294,177	2,767,329
Total net revenues		1,389,547	1,287,147
Income/(loss) before allocation of corporate overhead and income taxes		187,804	185,918
Allocation of corporate overhead		(45,676)	(42,649)
Income/(loss) after allocation of corporate overhead and before income taxes		142,128	143,269
Total assets		3,757,311	3,498,240
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,183,002	1,959,570
Gross outpatient revenues	[1]	246,460	221,643
Total net revenues	[1]	1,218,122	1,161,046
Income/(loss) before allocation of corporate overhead and income taxes	[1]	251,931	265,577
Allocation of corporate overhead	[1]	(39,661)	(38,716)
Income/(loss) after allocation of corporate overhead and before income taxes	[1]	212,270	226,861
Total assets	[1]	6,517,608	5,929,802
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues		0	0
Gross outpatient revenues		0	0
Total net revenues		5,189	1,605
Income/(loss) before allocation of corporate overhead and income taxes		(121,309)	(124,771)
Allocation of corporate overhead		85,337	81,365
Income/(loss) after allocation of corporate overhead and before income taxes		(35,972)	(43,406)
Total assets		$ 173,340	$ 136,967

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $101 million and $61 million for the three-month periods ended March 31, 2017 and 2016, respectively, and total U.K. behavioral health care facilities assets of approximately $992 million and $515 million as of March 31, 2017 and 2016, respectively.