Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2023		Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,548,138		$ 3,323,407	$ 7,015,656	$ 6,616,363
Percentage of Net Revenue		100.00%		100.00%	100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 409,770		$ 401,516	$ 815,760	$ 818,137
Percentage of Net Revenue		12.00%		12.00%	12.00%	12.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 430,586		$ 377,462	$ 849,695	$ 773,560
Percentage of Net Revenue		12.00%		11.00%	12.00%	12.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 349,850		$ 368,009	$ 666,332	$ 699,248
Percentage of Net Revenue		10.00%		11.00%	9.00%	11.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 569,213		$ 526,263	$ 1,160,462	$ 1,032,065
Percentage of Net Revenue		16.00%		16.00%	17.00%	16.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,088,876		$ 1,003,486	$ 2,134,968	$ 2,007,586
Percentage of Net Revenue		31.00%		30.00%	30.00%	30.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 190,114		$ 173,231	$ 357,903	$ 349,323
Percentage of Net Revenue		5.00%		5.00%	5.00%	5.00%
Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 210,448		$ 200,118	$ 453,082	$ 412,961
Percentage of Net Revenue		6.00%		6.00%	6.00%	6.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 299,281		$ 523,483	$ 577,454	$ 273,322
Percentage of Net Revenue		8.00%		8.00%	8.00%	8.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,003,079		$ 1,875,516	$ 3,976,611	$ 3,787,832
Percentage of Net Revenue		100.00%		100.00%	100.00%	100.00%
Acute Care Hospital Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 334,073		$ 318,166	$ 663,519	$ 655,275
Percentage of Net Revenue		17.00%		17.00%	17.00%	17.00%
Acute Care Hospital Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 344,975		$ 306,585	$ 689,007	$ 638,833
Percentage of Net Revenue		17.00%		16.00%	17.00%	17.00%
Acute Care Hospital Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 134,521		$ 184,098	$ 244,530	$ 339,934
Percentage of Net Revenue		7.00%		10.00%	6.00%	9.00%
Acute Care Hospital Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 171,824		$ 162,092	$ 364,122	$ 333,729
Percentage of Net Revenue		9.00%		9.00%	9.00%	9.00%
Acute Care Hospital Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 702,499		$ 627,475	$ 1,357,294	$ 1,266,370
Percentage of Net Revenue		35.00%		33.00%	34.00%	33.00%
Acute Care Hospital Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 0		$ 0	$ 0	$ 0
Percentage of Net Revenue		0.00%		0.00%	0.00%	0.00%
Acute Care Hospital Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 74,290		$ 74,123	$ 195,247	$ 166,233
Percentage of Net Revenue		4.00%		4.00%	5.00%	4.00%
Acute Care Hospital Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 240,897		$ 387,458	$ 462,892	$ 202,977
Percentage of Net Revenue		12.00%		10.00%	12.00%	11.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	$ 1,542,194		$ 1,433,920	$ 3,032,683	$ 2,800,387
Percentage of Net Revenue		100.00%		100.00%	100.00%	100.00%
Behavioral Health Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 75,697		$ 83,350	$ 152,241	$ 162,862
Percentage of Net Revenue		5.00%		6.00%	5.00%	6.00%
Behavioral Health Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 85,611		$ 70,877	$ 160,688	$ 134,727
Percentage of Net Revenue		6.00%		5.00%	5.00%	5.00%
Behavioral Health Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 215,329		$ 183,911	$ 421,802	$ 359,314
Percentage of Net Revenue		14.00%		13.00%	14.00%	13.00%
Behavioral Health Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 397,389		$ 364,171	$ 796,340	$ 698,336
Percentage of Net Revenue		26.00%		25.00%	26.00%	25.00%
Behavioral Health Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 386,377		$ 376,011	$ 777,674	$ 741,216
Percentage of Net Revenue		25.00%		26.00%	26.00%	26.00%
Behavioral Health Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 190,114		$ 173,231	$ 357,903	$ 349,323
Percentage of Net Revenue		12.00%		12.00%	12.00%	12.00%
Behavioral Health Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 136,158		$ 125,995	$ 257,835	$ 246,728
Percentage of Net Revenue		9.00%		9.00%	9.00%	9.00%
Behavioral Health Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 55,519		$ 107,881	$ 108,200	$ 56,374
Percentage of Net Revenue		4.00%		4.00%	4.00%	4.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,865	[1]	$ 13,971	$ 6,362	$ 28,144
Other | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,865		$ 28,144	$ 6,362	$ 13,971

[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.