Variable Interest Entities - Schedule of Consolidated VIEs Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 140,367	$ 133,813
Accounts receivable, net	299,022	281,332
Other current assets	90,710	79,886
Total current assets	530,099	495,031
Property and equipment, net	1,795,791	1,771,159
Goodwill	2,200,659	2,199,937
Intangible assets, net	70,319	70,145
Operating lease right-of-use assets	139,264	133,761
Total assets	4,834,639	4,768,078
Accounts payable	104,209	98,575
Accrued salaries and benefits	138,092	137,845
Current portion of operating lease liabilities	25,170	23,348
Other accrued liabilities	122,030	126,499
Total current liabilities	410,751	404,861
Operating lease liabilities	120,560	116,841
Other liabilities	117,062	110,505
Total liabilities	2,189,825	2,185,201
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	27,159	26,360
Accounts receivable, net	19,854	20,144
Other current assets	1,570	1,304
Total current assets	48,583	47,808
Property and equipment, net	236,765	220,793
Goodwill	34,945	34,945
Intangible assets, net	10,490	10,490
Operating lease right-of-use assets	6,524	6,603
Total assets	337,307	320,639
Accounts payable	3,736	3,690
Accrued salaries and benefits	6,139	5,656
Current portion of operating lease liabilities	206	197
Other accrued liabilities	8,325	6,818
Total current liabilities	18,406	16,361
Operating lease liabilities	6,614	6,666
Other liabilities	1,083	1,083
Total liabilities	$ 26,103	$ 24,110