Schedule of Disaggregates Revenue by Major Source (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Net revenues		$ 3,323,407	$ 3,197,880	$ 6,616,363	$ 6,210,867
Percentage of Net Revenue		100.00%	100.00%	100.00%	100.00%
Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 401,516	$ 400,938	$ 818,137	$ 824,943
Percentage of Net Revenue		12.00%	13.00%	12.00%	13.00%
Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 377,462	$ 335,925	$ 773,560	$ 669,027
Percentage of Net Revenue		11.00%	11.00%	12.00%	11.00%
Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 368,009	$ 397,229	$ 699,248	$ 662,010
Percentage of Net Revenue		11.00%	12.00%	11.00%	11.00%
Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 526,263	$ 495,463	$ 1,032,065	$ 965,719
Percentage of Net Revenue		16.00%	15.00%	16.00%	16.00%
Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,003,486	$ 960,952	$ 2,007,586	$ 1,908,506
Percentage of Net Revenue		30.00%	30.00%	30.00%	31.00%
UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 173,231	$ 172,220	$ 349,323	$ 336,886
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		$ 200,118	$ 213,101	$ 412,961	$ 427,634
Percentage of Net Revenue		6.00%	7.00%	6.00%	7.00%
Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 273,322	$ 222,052	$ 523,483	$ 416,142
Percentage of Net Revenue		8.00%	7.00%	8.00%	7.00%
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Net revenues		$ 1,875,516	$ 1,754,431	$ 3,787,832	$ 3,448,973
Percentage of Net Revenue		100.00%	100.00%	100.00%	100.00%
Acute Care Hospital Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 318,166	$ 308,211	$ 655,275	$ 643,724
Percentage of Net Revenue		17.00%	18.00%	17.00%	19.00%
Acute Care Hospital Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 306,585	$ 274,393	$ 638,833	$ 549,953
Percentage of Net Revenue		16.00%	16.00%	17.00%	16.00%
Acute Care Hospital Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 184,098	$ 169,705	$ 339,934	$ 281,346
Percentage of Net Revenue		10.00%	10.00%	9.00%	8.00%
Acute Care Hospital Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 162,092	$ 161,261	$ 333,729	$ 296,759
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		$ 627,475	$ 588,806	$ 1,266,370	$ 1,187,616
Percentage of Net Revenue		33.00%	34.00%	33.00%	34.00%
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		$ 74,123	$ 84,157	$ 166,233	$ 178,407
Percentage of Net Revenue		4.00%	5.00%	4.00%	5.00%
Acute Care Hospital Services | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 202,977	$ 167,898	$ 387,458	$ 311,168
Percentage of Net Revenue		11.00%	10.00%	10.00%	9.00%
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Net revenues	[1]	$ 1,433,920	$ 1,431,497	$ 2,800,387	$ 2,746,834
Percentage of Net Revenue		100.00%	100.00%	100.00%	100.00%
Behavioral Health Services | Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 83,350	$ 92,727	$ 162,862	$ 181,219
Percentage of Net Revenue		6.00%	6.00%	6.00%	7.00%
Behavioral Health Services | Managed Medicare
Disaggregation Of Revenue [Line Items]
Net revenues		$ 70,877	$ 61,532	$ 134,727	$ 119,074
Percentage of Net Revenue		5.00%	4.00%	5.00%	4.00%
Behavioral Health Services | Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 183,911	$ 227,524	$ 359,314	$ 380,664
Percentage of Net Revenue		13.00%	16.00%	13.00%	14.00%
Behavioral Health Services | Managed Medicaid
Disaggregation Of Revenue [Line Items]
Net revenues		$ 364,171	$ 334,202	$ 698,336	$ 668,960
Percentage of Net Revenue		25.00%	23.00%	25.00%	24.00%
Behavioral Health Services | Managed Care (HMO and PPOs)
Disaggregation Of Revenue [Line Items]
Net revenues		$ 376,011	$ 372,146	$ 741,216	$ 720,890
Percentage of Net Revenue		26.00%	26.00%	26.00%	26.00%
Behavioral Health Services | UK Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 173,231	$ 172,220	$ 349,323	$ 336,886
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		$ 125,995	$ 128,944	$ 246,728	$ 249,227
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		$ 56,374	$ 42,202	$ 107,881	$ 89,914
Percentage of Net Revenue		4.00%	3.00%	4.00%	3.00%
Other
Disaggregation Of Revenue [Line Items]
Net revenues		$ 13,971	$ 11,952	$ 28,144	$ 15,060
Other | Other Non-patient Revenue
Disaggregation Of Revenue [Line Items]
Net revenues		$ 13,971	$ 11,952	$ 28,144	$ 15,060

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $173 million and $172 million for the three-month periods ended June 30, 2022 and 2021, respectively, and approximately $349 million and $337 million for the six-month periods ended June 30, 2022 and 2021, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.220 billion and $1.369 billion as of June 30, 2022 and 2021, respectively.