Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Additional Information (Detail)

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Commitments and Contingencies - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]      
Rent expense for operating leases $ 23,800,000 $ 21,800,000 $ 19,200,000
Exposure per occurrence, employees compensation 250,000    
Aggregate self insured exposure per employer's liability 500,000    
Exposure per occurrence 500,000    
Aggregate self insured exposure per occurrence, foreign employees compensation 100,000    
Aggregate self insured exposure per employer's liability, foreign 1,000,000    
Auto liability claims 100,000    
Gross self insurance accruals 3,200,000 3,900,000  
Related insurance recoveries $ 1,900,000 $ 1,500,000  
Employment agreement, automatic renewal period 1 year    
Employment agreements, termination lump sum payments, period following change in control of company 2 years