Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,843,582	$ 3,467,518
Percentage of Net Revenue		100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 425,903	$ 405,990
Percentage of Net Revenue		11.00%	12.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 469,475	$ 419,109
Percentage of Net Revenue		12.00%	12.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 483,225	$ 316,482
Percentage of Net Revenue		13.00%	9.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 582,667	$ 591,249
Percentage of Net Revenue		15.00%	17.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,102,958	$ 1,046,092
Percentage of Net Revenue		29.00%	30.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 207,796	$ 167,789
Percentage of Net Revenue		5.00%	5.00%
Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 267,464	$ 242,634
Percentage of Net Revenue		7.00%	7.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 304,094	$ 278,173
Percentage of Net Revenue		8.00%	8.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,185,081	$ 1,973,532
Percentage of Net Revenue		100.00%	100.00%
Acute Care Hospital Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 349,087	$ 329,446
Percentage of Net Revenue		16.00%	17.00%
Acute Care Hospital Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 373,401	$ 344,032
Percentage of Net Revenue		17.00%	17.00%
Acute Care Hospital Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 234,862	$ 110,009
Percentage of Net Revenue		11.00%	6.00%
Acute Care Hospital Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 159,359	$ 192,298
Percentage of Net Revenue		7.00%	10.00%
Acute Care Hospital Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 698,785	$ 654,795
Percentage of Net Revenue		32.00%	33.00%
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		$ 123,333	$ 120,957
Percentage of Net Revenue		6.00%	6.00%
Acute Care Hospital Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 246,254	$ 221,995
Percentage of Net Revenue		11.00%	11.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	$ 1,656,067	$ 1,490,489
Percentage of Net Revenue		100.00%	100.00%
Behavioral Health Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 76,816	$ 76,544
Percentage of Net Revenue		5.00%	5.00%
Behavioral Health Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 96,074	$ 75,077
Percentage of Net Revenue		6.00%	5.00%
Behavioral Health Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 248,363	$ 206,473
Percentage of Net Revenue		15.00%	14.00%
Behavioral Health Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 423,308	$ 398,951
Percentage of Net Revenue		26.00%	27.00%
Behavioral Health Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 404,173	$ 391,297
Percentage of Net Revenue		24.00%	26.00%
Behavioral Health Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 207,796	$ 167,789
Percentage of Net Revenue		13.00%	11.00%
Behavioral Health Services | Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues		$ 144,131	$ 121,677
Percentage of Net Revenue		9.00%	8.00%
Behavioral Health Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 55,406	$ 52,681
Percentage of Net Revenue		3.00%	4.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,434	$ 3,497
Other | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 2,434	$ 3,497

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $208 million and $168 million for the three-month periods ended March 31, 2024 and 2023, respectively. Total assets at our U.K. behavioral health care facilities were approximately $1.336 billion and $1.265 billion as of March 31, 2024 and 2023, respectively.