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Shareholders' Equity and Equity Compensation (Additional Information) (Details)
12 Months Ended
Dec. 31, 2016
USD ($)
offering_periods
stock_purchase_right
$ / shares
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
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    
Stock-based compensation expense $ 11,275,000 $ 9,643,000 $ 7,533,000
Total intrinsic value of options exercised in period 2,100,000 6,700,000  
Cash received from exercise of options exercised 4,100,000 7,000,000  
Total grant-date fair value of stock options vested   200,000  
Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation expense $ 500,000 500,000 500,000
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    
Stock-based compensation expense   200,000 300,000
Performance Shares      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Nonvested awards, total compensation cost not yet recognized 5,900,000    
Stock-based compensation expense $ 4,600,000 3,200,000 2,300,000
Performance-based restricted stock measurement period 3 years    
Expected dividend yield 0.00%    
Future compensation cost, period of recognition 1 year 6 months    
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 $ 7,300,000    
Stock-based compensation expense $ 5,600,000 5,000,000 3,600,000
Future compensation cost, period of recognition 1 year 5 months    
Deferred Stock Units      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock-based compensation expense $ 700,000 $ 800,000 $ 800,000
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%