Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 11,592,749	$ 10,347,011
Gross outpatient revenues		4,827,484	4,941,480
Total net revenues		3,012,987	2,829,667
Income/(loss) before allocation of corporate overhead and income taxes		272,877	190,783
Allocation of corporate overhead		0	0
Income before income taxes		272,877	190,783
Total assets		13,096,329	11,620,426	$ 13,476,879
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		9,119,184	7,821,472
Gross outpatient revenues		4,580,720	4,681,741
Total net revenues		1,694,542	1,521,049
Income/(loss) before allocation of corporate overhead and income taxes		173,118	103,537
Allocation of corporate overhead		(58,107)	(55,973)
Income before income taxes		115,011	47,564
Total assets		4,957,253	4,387,355
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,473,565	2,525,539
Gross outpatient revenues	[1]	246,764	259,739
Total net revenues	[1]	1,315,337	1,306,109
Income/(loss) before allocation of corporate overhead and income taxes	[1]	231,325	237,683
Allocation of corporate overhead	[1]	(42,950)	(42,730)
Income before income taxes	[1]	188,375	194,953
Total assets	[1]	7,090,291	6,871,852
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues			0
Gross outpatient revenues			0
Total net revenues		3,108	2,509
Income/(loss) before allocation of corporate overhead and income taxes		(131,566)	(150,437)
Allocation of corporate overhead		101,057	98,703
Income before income taxes		(30,509)	(51,734)
Total assets		$ 1,048,785	$ 361,219

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $165 million and $137 million for the three-month periods ended March 31, 2021 and 2020, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.355 billion and $1.197 billion as of March 31, 2021 and 2020, respectively.