Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2023		Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 13,631,215		$ 12,268,284	$ 27,660,696	$ 24,943,989
Gross outpatient revenues		7,796,816		6,474,528	15,365,303	12,507,180
Total net revenues		3,548,138		3,323,407	7,015,656	6,616,363
Income/(loss) before allocation of corporate overhead and income taxes		224,695		209,730	438,796	409,713
Allocation of corporate overhead		0		0	0	0
Income before income taxes		224,695		209,730	438,796	409,713
Total assets		13,732,309		13,296,103	13,732,309	13,296,103	$ 13,494,188
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		10,960,845		9,706,731	22,362,336	19,945,962
Gross outpatient revenues		7,515,780		6,206,039	14,811,896	11,981,578
Total net revenues		2,003,079		1,875,516	3,976,611	3,787,832
Income/(loss) before allocation of corporate overhead and income taxes		130,527		95,059	263,823	243,739
Allocation of corporate overhead		(66,326)		(63,213)	133,588	125,497
Income before income taxes		64,201		31,846	130,235	118,242
Total assets		6,108,389		5,785,470	6,108,389	5,785,470
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,670,370		2,561,553	5,298,360	4,998,027
Gross outpatient revenues	[1]	281,036		268,489	553,407	525,602
Total net revenues	[1]	1,542,194		1,433,920	3,032,683	2,800,387
Income/(loss) before allocation of corporate overhead and income taxes	[1]	263,693		249,958	530,049	455,746
Allocation of corporate overhead	[1]	(46,679)		(45,063)	93,321	90,064
Income before income taxes	[1]	217,014		204,895	436,728	365,682
Total assets	[1]	7,365,545		7,251,966	7,365,545	7,251,966
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues
Gross outpatient revenues
Total net revenues		2,865	[1]	13,971	6,362	28,144
Income/(loss) before allocation of corporate overhead and income taxes		(169,525)		(135,287)	(355,076)	(289,772)
Allocation of corporate overhead		113,005		108,276	(226,909)	(215,561)
Income before income taxes		(56,520)		(27,011)	(128,167)	(74,211)
Total assets		$ 258,375		$ 258,667	$ 258,375	$ 258,667

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $190 million and $173 million for the three-month periods ended June 30, 2023 and 2022, respectively, and approximately $358 million and $349 million for the six-month periods ended June 30, 2023 and 2022, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.295 billion and $1.220 billion as of June 30, 2023 and 2022, respectively.