Commitments and Contingencies - Schedule of Changes in General and Professional Liability and Workers Compensation Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	$ 322,824	$ 314,941	$ 298,222
Plus: Accrued insurance expense, net of commercial premiums paid	159,223	105,672	92,863
Less: Payments made in settlement of self-insured claims	(113,083)	(97,789)	(76,144)
Ending balance	368,964	322,824	314,941
General and Professional Liability
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	241,820	243,051	228,691
Plus: Accrued insurance expense, net of commercial premiums paid	91,518	56,452	54,387
Less: Payments made in settlement of self-insured claims	(69,559)	(57,683)	(40,027)
Ending balance	263,779	241,820	243,051
Workers’ Compensation
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	81,004	71,890	69,531
Plus: Accrued insurance expense, net of commercial premiums paid	67,705	49,220	38,476
Less: Payments made in settlement of self-insured claims	(43,524)	(40,106)	(36,117)
Ending balance	$ 105,185	$ 81,004	$ 71,890