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Share-Based Compensation - Additional Information (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2016
USD ($)
share-based_compensation_plan
shares
Dec. 31, 2015
USD ($)
shares
Dec. 31, 2014
USD ($)
shares
Dec. 31, 2017
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Number of share-based compensation plans | share-based_compensation_plan 2      
Number of shares authorized (in shares) | shares 15,600,000      
Number of shares available for future issuance (in shares) | shares 5,400,000      
Proceeds from stock option exercises $ 30,240 $ 19,217 $ 17,161  
Forecast        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares issued (in shares) | shares       89,288
Stock Option        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock option exercisable life 10 years      
Total intrinsic value of options exercised $ 26,500 16,900 20,000  
Proceeds from stock option exercises 30,200 19,200 17,200  
Tax benefit realized for the tax deductions from stock options exercised 9,600 6,100 $ 7,300  
Total unrecognized compensation cost $ 10,800      
Weighted-average period of total unrecognized compensation cost, in years 1 year 4 months 24 days      
Stock Option | Non-Employee Directors Cliff        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period of option 1 year      
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost $ 5,300      
Weighted-average period of total unrecognized compensation cost, in years 1 year 1 month 6 days      
Unvested shares, granted (in shares) | shares 76,970      
Cash-settled Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period of option 3 years      
Share based compensation, accrued expenses $ 3,000 3,200    
Share based compensation, other noncurrent liabilities $ 2,400 $ 1,800    
Unvested shares, granted (in shares) | shares 41,060      
Performance Shares Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost $ 6,300      
Weighted-average period of total unrecognized compensation cost, in years 1 year      
Award requisite service period 3 years      
Unvested shares, granted (in shares) | shares 85,130 91,030 54,065  
Performance Shares Units | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Target award 0.00%      
Performance Shares Units | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Target award 250.00%      
Target payout 100.00%