Segment Reporting (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Total net revenues		$ 4,495,245	$ 3,963,027	$ 12,878,781	$ 11,714,213
Salaries, wages and benefits		2,071,898	1,912,308	6,037,953	5,611,304
Other segment item operating expenses		1,294,721	1,090,197	3,563,039	3,165,483
Depreciation and amortization expense		155,060	149,567	455,409	438,050
Other (income) expense, net		(13,629)	(2,028)	(27,767)	3,315
Reportable segment income before income taxes		496,886	341,533	1,390,699	1,059,625
Interest expense, net		38,431	44,660	113,851	146,385
Operating Segments
Segment Reporting Information [Line Items]
Total net revenues		4,490,324	3,960,431	12,868,312	11,706,297
Material Reconciling Items
Segment Reporting Information [Line Items]
Total net revenues		4,921	2,596	10,469	7,916
Reportable segment income before income taxes		645,371	518,180	1,867,518	1,615,785
Corporate Nonsegment
Segment Reporting Information [Line Items]
Total net revenues		4,921	2,596	10,469	7,916
Other segment item operating expenses	[1]	130,507	137,341	395,090	418,053
Other (income) expense, net		(13,739)	(640)	(17,032)	6,077
Reportable segment income before income taxes		496,886	341,533	1,390,699	1,059,625
Interest expense, net		36,638	42,542	109,230	139,946
Acute Care Hospital Services
Segment Reporting Information [Line Items]
Total net revenues		2,630,065	2,253,819	7,380,328	6,617,586
Acute Care Hospital Services | Operating Segments
Segment Reporting Information [Line Items]
Total net revenues		2,630,065	2,253,819	7,380,328	6,617,586
Acute Care Hospital Services | Material Reconciling Items
Segment Reporting Information [Line Items]
Salaries, wages and benefits		973,680	899,375	2,821,509	2,620,069
Other segment item operating expenses	[2]	1,258,986	1,058,086	3,490,402	3,095,859
Depreciation and amortization expense		97,389	94,747	288,406	279,420
Interest (income) expense, net		528	1,077	1,177	3,363
Other (income) expense, net		(623)	(527)	(9,806)	(354)
Reportable segment income before income taxes		300,105	201,061	788,640	619,229
Behavioral Health Services
Segment Reporting Information [Line Items]
Total net revenues		1,860,259	1,706,612	5,487,984	5,088,711
Behavioral Health Services | Operating Segments
Segment Reporting Information [Line Items]
Total net revenues	[3]	1,860,259	1,706,612	5,487,984	5,088,711
Behavioral Health Services | Material Reconciling Items
Segment Reporting Information [Line Items]
Salaries, wages and benefits	[3]	995,570	914,477	2,900,892	2,682,167
Other segment item operating expenses	[2],[3]	462,131	422,609	1,345,738	1,258,743
Depreciation and amortization expense	[3]	55,294	52,227	159,961	150,577
Interest (income) expense, net	[3]	1,265	1,041	3,444	3,076
Other (income) expense, net	[3]	733	(861)	(929)	(2,408)
Reportable segment income before income taxes	[3]	345,266	317,119	1,078,878	996,556
Other
Segment Reporting Information [Line Items]
Total net revenues		$ 4,921	$ 2,596	$ 10,469	$ 7,916

[1] Non-segment operating expenses for each period includes salaries, wages and benefits, other operating expenses, supplies expense and lease and rental expense.

[2] Other segment operating expenses for each period includes other operating expenses, supplies expense and lease and rental expense.

[3] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $264 million and $230 million for the three-month periods ended September 30, 2025 and 2024, respectively, and approximately $738 million and $651 million for the nine-month periods ended September 30, 2025 and 2024, respectively.