Commitments and Contingencies - Schedule of Changes in General and Professional Liability and Workers Compensation Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	$ 298,222	$ 274,815	$ 271,476
Liabilities assumed in acquisition			661
Plus: Accrued insurance expense, net of commercial premiums paid	92,863	102,595	84,638
Less: Payments made in settlement of self-insured claims	(76,144)	(79,188)	(81,960)
Ending balance	314,941	298,222	274,815
General and Professional Liability
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	228,691	207,459	203,973
Liabilities assumed in acquisition			0
Plus: Accrued insurance expense, net of commercial premiums paid	54,387	65,049	54,671
Less: Payments made in settlement of self-insured claims	(40,027)	(43,817)	(51,185)
Ending balance	243,051	228,691	207,459
Workers’ Compensation
Commitments and Contingencies Disclosure [Line Items]
Beginning balance	69,531	67,356	67,503
Liabilities assumed in acquisition			661
Plus: Accrued insurance expense, net of commercial premiums paid	38,476	37,546	29,967
Less: Payments made in settlement of self-insured claims	(36,117)	(35,371)	(30,775)
Ending balance	$ 71,890	$ 69,531	$ 67,356