Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation Of Revenue [Line Items]
Net revenues	$ 4,283,816	$ 3,907,604	$ 8,383,536	$ 7,751,186
Percentage of Net Revenue	100.00%	100.00%	100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 449,247	$ 414,408	$ 917,286	$ 840,311
Percentage of Net Revenue	10.00%	11.00%	11.00%	11.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 519,172	$ 472,692	$ 1,039,471	$ 942,167
Percentage of Net Revenue	12.00%	12.00%	12.00%	12.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 644,120	$ 532,968	$ 1,171,028	$ 1,016,193
Percentage of Net Revenue	15.00%	14.00%	14.00%	13.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 619,608	$ 568,997	$ 1,222,437	$ 1,151,664
Percentage of Net Revenue	14.00%	15.00%	15.00%	15.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues	$ 1,227,853	$ 1,127,197	$ 2,412,654	$ 2,230,155
Percentage of Net Revenue	29.00%	29.00%	29.00%	29.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues	$ 246,906	$ 212,706	$ 473,974	$ 420,502
Percentage of Net Revenue	6.00%	5.00%	6.00%	5.00%
Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues	$ 310,054	$ 284,295	$ 620,127	$ 551,759
Percentage of Net Revenue	7.00%	7.00%	7.00%	7.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues	$ 266,856	$ 294,341	$ 526,559	$ 598,435
Percentage of Net Revenue	6.00%	8.00%	6.00%	8.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues	$ 2,401,034	$ 2,178,686	$ 4,750,263	$ 4,363,767
Percentage of Net Revenue	100.00%	100.00%	100.00%	100.00%
Acute Care Hospital Services \| Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 375,454	$ 338,635	$ 767,015	$ 687,722
Percentage of Net Revenue	16.00%	16.00%	16.00%	16.00%
Acute Care Hospital Services \| Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 412,153	$ 370,108	$ 832,015	$ 743,509
Percentage of Net Revenue	17.00%	17.00%	18.00%	17.00%
Acute Care Hospital Services \| Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 281,157	$ 240,577	$ 532,022	$ 475,439
Percentage of Net Revenue	12.00%	11.00%	11.00%	11.00%
Acute Care Hospital Services \| Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 170,180	$ 154,550	$ 328,594	$ 313,909
Percentage of Net Revenue	7.00%	7.00%	7.00%	7.00%
Acute Care Hospital Services \| Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues	$ 810,631	$ 706,268	$ 1,590,779	$ 1,405,053
Percentage of Net Revenue	34.00%	32.00%	33.00%	32.00%
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	$ 147,114	$ 134,201	$ 296,340	$ 257,534
Percentage of Net Revenue	6.00%	6.00%	6.00%	6.00%
Acute Care Hospital Services \| Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues	$ 204,345	$ 234,347	$ 403,498	$ 480,601
Percentage of Net Revenue	9.00%	11.00%	8.00%	11.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	$ 1,880,076	$ 1,726,032	$ 3,627,725	$ 3,382,099
Percentage of Net Revenue	100.00%	100.00%	100.00%	100.00%
Behavioral Health Services \| Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 73,793	$ 75,773	$ 150,271	$ 152,589
Percentage of Net Revenue	4.00%	4.00%	4.00%	5.00%
Behavioral Health Services \| Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues	$ 107,019	$ 102,584	$ 207,456	$ 198,658
Percentage of Net Revenue	6.00%	6.00%	6.00%	6.00%
Behavioral Health Services \| Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 362,963	$ 292,391	$ 639,006	$ 540,754
Percentage of Net Revenue	19.00%	17.00%	18.00%	16.00%
Behavioral Health Services \| Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues	$ 449,428	$ 414,447	$ 893,843	$ 837,755
Percentage of Net Revenue	24.00%	24.00%	25.00%	25.00%
Behavioral Health Services \| Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues	$ 417,222	$ 420,929	$ 821,875	$ 825,102
Percentage of Net Revenue	22.00%	24.00%	23.00%	24.00%
Behavioral Health Services \| UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues	$ 246,906	$ 212,706	$ 473,974	$ 420,502
Percentage of Net Revenue	13.00%	12.00%	13.00%	12.00%
Behavioral Health Services \| Other Patient Revenue and Adjustments, Net
Disaggregation Of Revenue [Line Items]
Net revenues	$ 162,940	$ 150,094	$ 323,787	$ 294,225
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	$ 59,805	$ 57,108	$ 117,513	$ 112,514
Percentage of Net Revenue	3.00%	3.00%	3.00%	3.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues	$ 2,706	$ 2,886	$ 5,548	$ 5,320
Other \| Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues	$ 2,706	$ 2,886	$ 5,548	$ 5,320