Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Workers Compensation Reserve [Abstract]
Workers' compensation claims liabilities, Beginning balance	$ 241,510	$ 315,733	$ 279,407	$ 357,746
Add: claims expense accrual
Current period	4,854	2,394	13,678	71,407
Prior periods	(1,360)	(823)	(10,737)	(7,486)
Total expense accrual	3,494	1,571	2,941	63,921
Less: claim payments related to
Current period	1,714	6,149	2,742	11,129
Prior periods	16,846	14,018	53,136	113,022
Total paid	18,560	20,167	55,878	124,151
Change in claims incurred in excess of retention limits	899	(138)	873	(517)
Workers' compensation claims liabilities, Ending balance	227,343	296,999	227,343	296,999
Incurred but not reported (IBNR)	$ 117,587	$ 162,382	$ 117,587	$ 162,382
Ratio of IBNR to workers' compensation claims liabilities	52.00%	55.00%	52.00%	55.00%