Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Gross inpatient revenues		$ 9,022,136	$ 9,599,551	$ 19,369,147	$ 19,247,264
Gross outpatient revenues		3,610,854	4,671,001	8,552,334	9,195,161
Total net revenues		2,729,754	2,855,168	5,559,421	5,659,559
Income/(loss) before allocation of corporate overhead and income taxes		335,658	310,808	526,441	607,104
Allocation of corporate overhead		0	0	0	0
Income before income taxes		335,658	310,808	526,441	607,104
Total assets		12,148,499	11,752,650	12,148,499	11,752,650	$ 11,668,250
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Gross inpatient revenues		6,736,777	7,051,925	14,558,249	14,215,639
Gross outpatient revenues		3,394,680	4,402,308	8,076,421	8,659,922
Total net revenues		1,467,506	1,531,709	2,988,555	3,046,553
Income/(loss) before allocation of corporate overhead and income taxes		182,996	188,157	286,533	380,370
Allocation of corporate overhead		(55,983)	(57,528)	(111,956)	(115,028)
Income before income taxes		127,013	130,629	174,577	265,342
Total assets		4,467,698	4,413,509	4,467,698	4,413,509
Behavioral Health Services
Segment Reporting Information [Line Items]
Gross inpatient revenues	[1]	2,285,359	2,547,626	4,810,898	5,031,625
Gross outpatient revenues	[1]	216,174	268,693	475,913	535,239
Total net revenues	[1]	1,259,123	1,320,241	2,565,232	2,606,624
Income/(loss) before allocation of corporate overhead and income taxes	[1]	256,766	265,986	494,449	510,154
Allocation of corporate overhead	[1]	(42,750)	(41,638)	(85,480)	(83,285)
Income before income taxes	[1]	214,016	224,348	408,969	426,869
Total assets	[1]	6,819,694	6,933,825	6,819,694	6,933,825
Other
Segment Reporting Information [Line Items]
Gross inpatient revenues			0	0	0
Gross outpatient revenues			0	0	0
Total net revenues		3,125	3,218	5,634	6,382
Income/(loss) before allocation of corporate overhead and income taxes		(104,104)	(143,335)	(254,541)	(283,420)
Allocation of corporate overhead		98,733	99,166	197,436	198,313
Income before income taxes		(5,371)	(44,169)	(57,105)	(85,107)
Total assets		$ 861,107	$ 405,316	$ 861,107	$ 405,316

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $136 million and $144 million for the three-month periods ended June 30, 2020 and 2019, respectively, and approximately $273 million and $281 million for the six-month periods ended June 30, 2020 and 2019, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.192 billion and $1.217 billion as of June 30, 2020 and 2019, respectively.