Revenue - Schedule of U.S. Revenue and Percentage Generated by Each Payor Type (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 833,304	$ 777,251	$ 2,366,425	$ 2,327,230
U.S. Facilities [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 547,961	$ 509,383	$ 1,548,653	$ 1,507,156
Revenue, Percentage	100.00%	100.00%	100.00%	100.00%
U.S. Facilities [Member] | Commercial [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 156,741	$ 140,315	$ 439,911	$ 426,659
Revenue, Percentage	28.60%	27.50%	28.40%	28.30%
U.S. Facilities [Member] | Medicare [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 96,536	$ 76,906	$ 244,721	$ 223,027
Revenue, Percentage	17.60%	15.10%	15.90%	14.80%
U.S. Facilities [Member] | Medicaid [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 261,341	$ 256,370	$ 767,075	$ 750,631
Revenue, Percentage	47.70%	50.30%	49.40%	49.80%
U.S. Facilities [Member] | Self-Pay [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 26,060	$ 30,626	$ 75,570	$ 91,982
Revenue, Percentage	4.80%	6.00%	4.90%	6.10%
U.S. Facilities [Member] | Other [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Revenue	$ 7,283	$ 5,166	$ 21,376	$ 14,857
Revenue, Percentage	1.30%	1.10%	1.40%	1.00%