Quarterly report pursuant to Section 13 or 15(d)

Workers' Compensation Claims - Additional Information (Detail)

v3.20.2
Workers' Compensation Claims - Additional Information (Detail) - USD ($)
6 Months Ended 12 Months Ended
Jul. 01, 2020
Jun. 30, 2020
Dec. 31, 2019
Jun. 29, 2020
Mar. 31, 2020
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Worker's compensation risk claim maximum   $ 5,000,000.0            
Balance in Chubb trust accounts   264,600,000 $ 393,500,000 $ 115,700,000        
Collateral securities maintain to cover potential workers compensation claims losses   59,700,000 59,700,000          
Surety bonds and standby letters of credit   59,700,000            
Claim payments receivable from Chubb   2,200,000            
Estimated future liability for unsettled workers' compensation   336,504,000 438,986,000   $ 445,310,000 $ 430,736,000 $ 422,872,000 $ 413,397,000
Reserves incurred in excess of retention limits   3,400,000 3,300,000          
Other Assets [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Accrual for costs incurred in excess of retention limits offset by a receivable   3,400,000 $ 3,300,000          
Wells Fargo Bank, National Association [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Letter of credit   63,700,000            
Subsequent Event [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Worker's compensation risk claim maximum $ 3,000,000.0              
Maryland [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Reinsurance coverage   1,000,000.0            
Maryland [Member] | Subsequent Event [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Reinsurance coverage 1,000,000.0              
Colorado [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Reinsurance coverage   2,000,000.0            
Colorado [Member] | Subsequent Event [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Reinsurance coverage $ 2,000,000.0              
California [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Surety bonds and standby letters of credit   $ 39,200,000