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Share-Based Compensation - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Common shares available for issuance under share-based compensation plan (shares) 3,400,000    
Total share-based compensation expense $ 16,376 $ 11,911 $ 12,042
Recognized tax benefits from share-based compensation expense 4,300 4,600 4,500
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Unrecognized compensation would be recognized based on accelerated vesting provisions $ 1,400    
Restricted Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period (in years) 3 years    
Total unrecognized compensation cost related to nonvested awards $ 21,700    
Total unrecognized compensation cost related to nonvested awards, period for recognition 2 years 2 months 12 days    
Value of stock that vested during the period $ 19,500 $ 11,900 $ 11,000
Restricted Stock | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period (in years) 1 year    
Restricted Stock | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period (in years) 5 years    
Performance Shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period (in years) 3 years    
Total unrecognized compensation cost related to nonvested awards $ 1,700    
Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period (in years) 3 years    
Stock option grants in period (shares) 0 0 0
Stock Options | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award expiration period, years 7 years    
Stock Options | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award expiration period, years 10 years