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Stock-Based Compensation - Restricted Stock Activity (Details) - Restricted Stock - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Period for share issuance after vesting 30 days    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding (in shares) 297,797    
Granted (in shares) 148,120 185,054  
Vested (in shares) (97,095)    
Forfeited (in shares) (15,856)    
Outstanding (in shares) 332,966 297,797  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]      
Outstanding, weighted-average grant date fair value (in dollars per share) $ 47.95    
Granted, weighted-average grant date fair value (in dollars per share) 53.41 $ 46.90 $ 51.68
Vested, weighted-average grant date fair value (in dollars per share) 48.97    
Forfeited, weighted-average grant date fair value (in dollars per share) 53.00    
Outstanding, weighted-average grant date fair value (in dollars per share) $ 49.84 $ 47.95  
Total compensation cost not yet recognized $ 10.0 $ 9.1  
Total compensation cost not yet recognized, period for recognition 2 years 8 months 12 days 2 years 6 months  
Total fair value of shares vested $ 5.4 $ 6.5 $ 4.3
Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 3 years    
Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 4 years