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Share-Based Compensation - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
May 24, 2016
May 22, 2007
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock authorized to be issued under plan (in shares) 3,800,000.0        
Unrecognized pre-tax compensation cost     $ 8,300    
Weighted average recognition period (in years)     2 years 3 months 15 days    
Total intrinsic value of options exercised during period     $ 4,500 $ 4,900 $ 7,400
Cash received from options exercised during period     2,259 $ 2,063 $ 2,795
2007 Long-Term Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock authorized to be issued under plan (in shares) 400,000.0 3,300,000.0      
Exercise price of shares granted may not be less than fair market value (percentage)   100.00%      
2007 Long-Term Incentive Plan | Restricted Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized pre-tax compensation cost     $ 6,500    
Weighted average recognition period (in years)     1 year 10 months 6 days    
Annual vesting, percentage     20.00%    
2016 Long-Term Incentive Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock authorized to be issued under plan (in shares) 3,400,000.0        
Exercise price of shares granted may not be less than fair market value (percentage) 100.00%