Schedule of Disaggregates Revenue by Major Source (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Revenues		$ 2,912,541	$ 2,822,453	$ 8,471,962	$ 8,482,012
Acute Care Hospital Services
Disaggregation Of Revenue [Line Items]
Revenues		1,610,003	1,528,535	4,598,558	4,575,088
Acute Care Hospital Services | CARES Act and Other Grant Income
Disaggregation Of Revenue [Line Items]
Revenues		4,000		161,000
Behavioral Health Services
Disaggregation Of Revenue [Line Items]
Revenues	[1]	1,299,591	$ 1,291,816	3,864,823	$ 3,898,440
Behavioral Health Services | CARES Act and Other Grant Income
Disaggregation Of Revenue [Line Items]
Revenues		$ 9,000		$ 52,000

[1] Includes net revenues generated from our behavioral health care facilities located in the U.K. amounting to approximately $156 million and $135 million for the three-month periods ended September 30, 2020 and 2019, respectively, and approximately $429 million and $415 million for the nine-month periods ended September 30, 2020 and 2019, respectively.  Total assets at our U.K. behavioral health care facilities were approximately $1.257 billion and $1.175 billion as of September 30, 2020 and 2019, respectively.