Quarterly report pursuant to Section 13 or 15(d)

Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail)

v3.20.2
Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Workers Compensation Reserve [Abstract]        
Workers' compensation claims liabilities, Beginning balance $ 336,504 $ 430,736 $ 438,986 $ 413,397
Add: claims expense accrual        
Current period 35,138 37,404 106,359 118,934
Prior periods (2,977) (5,593) (5,163) (10,245)
Total expense accrual 32,161 31,811 101,196 108,689
Less: claim payments related to        
Current period 7,046 8,609 13,123 14,213
Prior periods 15,640 23,815 181,170 77,619
Total paid 22,686 32,424 194,293 91,832
Change in claims incurred in excess of retention limits 1,369 (77) 1,459 (208)
Workers' compensation claims liabilities, Ending balance 347,348 430,046 347,348 430,046
Incurred but not reported (IBNR) $ 203,595 $ 274,344 $ 203,595 $ 274,344
Ratio of IBNR to workers' compensation claims liabilities 59.00% 64.00% 59.00% 64.00%