Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,292,956	$ 3,012,987
Percentage of Net Revenue		100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 416,621	$ 424,005
Percentage of Net Revenue		13.00%	14.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 396,098	$ 333,102
Percentage of Net Revenue		12.00%	11.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 331,239	$ 264,781
Percentage of Net Revenue		10.00%	9.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 505,802	$ 470,256
Percentage of Net Revenue		15.00%	16.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,004,100	$ 947,554
Percentage of Net Revenue		30.00%	31.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 176,092	$ 164,666
Percentage of Net Revenue		5.00%	5.00%
Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 212,843	$ 214,533
Percentage of Net Revenue		6.00%	7.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 250,161	$ 194,090
Percentage of Net Revenue		8.00%	6.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,912,316	$ 1,694,542
Percentage of Net Revenue		100.00%	100.00%
Acute Care Hospital Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 337,109	$ 335,513
Percentage of Net Revenue		18.00%	20.00%
Acute Care Hospital Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 332,248	$ 275,560
Percentage of Net Revenue		17.00%	16.00%
Acute Care Hospital Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 155,836	$ 111,641
Percentage of Net Revenue		8.00%	7.00%
Acute Care Hospital Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 171,637	$ 135,498
Percentage of Net Revenue		9.00%	8.00%
Acute Care Hospital Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 638,895	$ 598,810
Percentage of Net Revenue		33.00%	35.00%
Acute Care Hospital Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 0	$ 0
Percentage of Net Revenue		0.00%	0.00%
Acute Care Hospital Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 92,110	$ 94,250
Percentage of Net Revenue		5.00%	6.00%
Acute Care Hospital Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 184,481	$ 143,270
Percentage of Net Revenue		10.00%	8.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	$ 1,366,467	$ 1,315,337
Percentage of Net Revenue		100.00%	100.00%
Behavioral Health Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 79,512	$ 88,492
Percentage of Net Revenue		6.00%	7.00%
Behavioral Health Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 63,850	$ 57,542
Percentage of Net Revenue		5.00%	4.00%
Behavioral Health Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 175,403	$ 153,140
Percentage of Net Revenue		13.00%	12.00%
Behavioral Health Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 334,165	$ 334,758
Percentage of Net Revenue		24.00%	25.00%
Behavioral Health Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 365,205	$ 348,744
Percentage of Net Revenue		27.00%	27.00%
Behavioral Health Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 176,092	$ 164,666
Percentage of Net Revenue		13.00%	13.00%
Behavioral Health Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 120,733	$ 120,283
Percentage of Net Revenue		9.00%	9.00%
Behavioral Health Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 51,507	$ 47,712
Percentage of Net Revenue		4.00%	4.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues		$ 14,173	$ 3,108
Other | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 14,173	$ 3,108

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $176 million and $165 million for the three-month periods ended March 31, 2022 and 2021, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.320 billion and $1.355 billion as of March 31, 2022 and 2021, respectively.