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Stock-Based Compensation (Additional Information) (Details)
3 Months Ended 9 Months Ended 63 Months Ended
Sep. 30, 2017
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
offering_periods
Sep. 30, 2016
USD ($)
Jun. 30, 2017
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Proceeds from the exercise of stock options, net     $ 1,926,000 $ 2,058,000  
Deferred Stock Units          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense (income) $ 100,000 $ 0 $ 1,000,000 700,000  
Employee Stock Option          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock options, contractual term (years)     10 years    
Stock options, grants in period, gross | shares         0
Options exercised, total intrinsic value     $ 3,000,000    
Performance-Based Restricted Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted stock award program, measurement period (years)     3 years    
Expected dividend yield (percent)     0.00%    
Compensation expense (income) 1,400,000 1,100,000 $ 2,900,000 3,200,000  
Performance-Based Restricted Stock | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted stock award program, awarded shares as a percentage of the original award amount (percent)     0.00%    
Performance-Based Restricted Stock | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Restricted stock award program, awarded shares as a percentage of the original award amount (percent)     200.00%    
Time Based Restricted Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense (income) 1,600,000 1,600,000 $ 4,200,000 4,300,000  
Employee Stock Purchase Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Compensation expense (income) $ 100,000 $ 300,000 $ 100,000 $ 300,000  
Employee stock purchase plan, number of offering (offering period) | offering_periods     2    
Employee stock purchase plan, offering period (months)     6 months    
Employee stock purchase plan, purchase price discount (percent)     15.00%