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Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Additional disclosures [Abstract]      
Stock-based compensation expense $ 4,581 $ 4,210 $ 3,936
Number of shares available for future grant (in shares) 781,123    
Stock Options [Member]      
Share-based compensation [Abstract]      
Stock awards termination period 10 years    
Stock options [Roll Forward]      
Outstanding, beginning of period (in shares) 33,145    
Exercised (in shares) (8,845)    
Expired (in shares) (10,500)    
Outstanding, end of period (in shares) 13,800 33,145  
Exercisable, end of period (in shares) 13,800    
Stock options, weighted average exercise price [Abstract]      
Outstanding, beginning of period (in dollars per share) $ 23.73    
Exercised (in dollars per share) 20.87    
Expired (in dollars per share) 20.74    
Outstanding, end of period (in dollars per share) 27.83 $ 23.73  
Exercisable, end of period (in dollars per share) $ 27.83    
Additional disclosures [Abstract]      
Weighted average remaining contractual term, outstanding, end of period 3 years 4 months 9 days    
Weighted average remaining contractual term, exercisable, end of period 3 years 4 months 9 days    
Aggregate intrinsic value, outstanding, end of period $ 75    
Aggregate intrinsic value, exercisable, end of period 75    
Stock-based compensation expense 0 $ 1 11
Proceeds from stock options exercised 185 725 999
Tax benefits related to stock options exercised 41 123 173
Intrinsic value of stock options exercised 165 490 692
Fair value of shares vested during the year 0 13 16
Restricted Stock [Member]      
Additional disclosures [Abstract]      
Stock-based compensation expense $ 4,600 $ 4,200 3,900
Restricted Stock [Member] | Employees [Member] | Minimum [Member]      
Share-based compensation [Abstract]      
Stock awards vesting period 3 years    
Restricted Stock [Member] | Employees [Member] | Maximum [Member]      
Share-based compensation [Abstract]      
Stock awards vesting period 5 years    
Restricted Stock [Member] | Non-employee Directors [Member]      
Share-based compensation [Abstract]      
Stock awards vesting period 3 years    
Restricted Stock Units (RSUs) [Member]      
Restricted stock and restricted stock units [Roll Forward]      
Unvested, beginning of period (in shares) 555,440    
Forfeited (in shares) (2,315)    
Vested (in shares) (115,432)    
Granted (in shares) 147,562    
Unvested, end of period (in shares) 585,255 555,440  
Restricted stock and restricted stock units, weighted average grant date fair value [Abstract]      
Unvested, beginning of period (in dollars per share) $ 30.11    
Forfeited (in dollars per share) 34.82    
Vested (in dollars per share) 29.93    
Granted (in dollars per share) 28.61    
Unvested, end of period (in dollars per share) $ 29.78 $ 30.11  
Restricted Stock Awards and Stock Units [Member]      
Additional disclosures [Abstract]      
Tax benefit on restricted stock awards $ 1,000 $ 1,100 $ 1,200
Unrecognized compensation cost $ 5,100    
Unrecognized compensation cost, weighted average period of recognition 1 year 6 months