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Stock-Based Compensation - Additional Information (Details)
1 Months Ended 3 Months Ended 9 Months Ended
May 31, 2018
shares
Sep. 30, 2019
USD ($)
plan
$ / shares
shares
Sep. 30, 2018
USD ($)
Sep. 30, 2019
USD ($)
plan
$ / shares
shares
Sep. 30, 2018
USD ($)
$ / shares
Dec. 31, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Number of compensation plans | plan   2   2    
Granted (shares) | shares       0    
Total intrinsic value of stock options exercised   $ 1,000,000.0 $ 4,700,000 $ 1,300,000 $ 7,500,000  
Fair value of stock options vested   600,000 100,000 4,900,000 3,200,000  
Allocated share-based compensation expense   $ 3,117,000 2,025,000 $ 7,933,000 $ 5,097,000  
Black-Scholes Option Valuation Model            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option weighted average grant date fair value (in dollars per share) | $ / shares         $ 23.43  
Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Weighted average fair value (USD per share) | $ / shares   $ 47.81   $ 47.81   $ 42.66
Award vesting period       3 years    
Performance Shares            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Weighted average fair value (USD per share) | $ / shares   $ 66.16   $ 66.16    
Award vesting period       3 years    
Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares outstanding (in shares) | shares   644,943   644,943   792,943
Restricted Stock and Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Allocated share-based compensation expense   $ 3,400,000 $ 2,300,000 $ 8,700,000 $ 5,700,000  
Unrecognized stock-based compensation expense   $ 12,200,000   $ 12,200,000    
Weighted average, expected recognition period       2 years 1 month 6 days    
2019 Awards | Year One | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2019 Awards | Year One | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2019 Awards | Year Two | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2019 Awards | Year Two | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2019 Awards | Year Three | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2019 Awards | Year Three | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year One | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year One | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year Two | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year Two | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year Three | Restricted Stock Units            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2018 Awards | Year Three | Employee Stock Option            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Vesting installment (as a percent)       33.33%    
2014 Plan            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Additional shares authorized (in shares) | shares 1,000,000          
Shares authorized (in shares) | shares 2,974,543          
Shares outstanding (in shares) | shares   0   0    
2004 Equity Incentive Plan            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Shares authorized (in shares) | shares 891,960          
Directors Plan | Restricted Stock            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Term for value of shares to be granted upon election       $ 100,000    
Directors Plan | Restricted Stock | Independent Chairman of the Board            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Term for value of shares to be granted upon election       50,000    
Directors Plan | Restricted Stock | Lead Director            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Term for value of shares to be granted upon election       $ 40,000