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Shareholders' Equity and Equity Compensation (Additional Information) (Details)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2015
USD ($)
stock_purchase_right
offering_periods
$ / shares
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Lower limit of exercise price range 50.00%    
Vesting period 4 years    
Expiration period 10 years    
Stock purchase right | stock_purchase_right 1    
Stock repurchase right exercise price (in dollars per share) | $ / shares $ 240.00    
Class of warrant or right, exercise price of warrants or rights (in dollars per share) | $ / shares $ 0.01    
Total intrinsic value of options exercised in period $ 6,700 $ 9,400  
Cash received from exercise of options exercised 7,000 20,500  
Total grant-date fair value of stock options vested 0 300  
Stock-based compensation expense 9,643 7,533 $ 5,393
Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation expense $ 500 500 500
Employee stock purchase plan number of offering periods | offering_periods 2    
Employee stock purchase plan length of offering periods 6 months    
Discount from market price percentage 15.00%    
Equity Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expiration period 10 years    
Annual forfeiture rate 3.00%    
Nonvested awards, total compensation cost not yet recognized $ 0    
Future compensation cost, period of recognition 1 month    
Stock-based compensation expense $ 200 300 400
Performance Shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected dividend yield 0.00%    
Nonvested awards, total compensation cost not yet recognized $ 6,000    
Future compensation cost, period of recognition 1 year 5 months    
Stock-based compensation expense $ 3,200 2,300 1,300
Performance-based restricted stock measurement period 3 years    
Performance Shares | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance-based restricted stock award percentage target 200.00%    
Performance Shares | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance-based restricted stock award percentage target 0.00%    
Time Based Restricted Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Nonvested awards, total compensation cost not yet recognized $ 7,900    
Future compensation cost, period of recognition 1 year 6 months    
Stock-based compensation expense $ 5,000 3,600 2,500
Deferred Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation expense $ 800 $ 800 $ 700
Director      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expiration period 10 years    
Vesting on the second anniversary after the grant date | Employee stock option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options vesting percentage 33.33%    
Vesting on the third anniversary after the grant date | Employee stock option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options vesting percentage 33.33%    
Vesting on the fourth anniversary after the grant date | Employee stock option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options vesting percentage 33.34%