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Stock-Based Compensation Plans (Details)
$ / shares in Units, $ in Thousands
9 Months Ended
Sep. 30, 2021
USD ($)
Type
$ / shares
shares
Sep. 30, 2020
USD ($)
May 31, 2021
shares
Restricted and Performance Stock Grants [Abstract]      
Number of types of restricted stock | Type 2    
Additional Disclosures [Abstract]      
Compensation expense, gross | $ $ 7,189 $ 6,067  
Restricted Shares [Member] | Minimum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Expiration of vesting period 3 years    
Restricted Shares [Member] | Employees [Member]      
Restricted and Performance Stock Grants [Abstract]      
Estimated forfeitures 5.00%    
Restricted Shares [Member] | Executives [Member]      
Restricted and Performance Stock Grants [Abstract]      
Estimated forfeitures 0.00%    
Restricted Shares [Member] | Directors [Member]      
Restricted and Performance Stock Grants [Abstract]      
Estimated forfeitures 0.00%    
Restricted Shares [Member] | Age 60 [Member] | Executives [Member]      
Restricted and Performance Stock Grants [Abstract]      
Vesting percentage 25.00%    
Vesting period before reaching age limit 2 months    
Restricted Shares [Member] | Age 63 [Member] | Executives [Member]      
Restricted and Performance Stock Grants [Abstract]      
Vesting percentage 25.00%    
Vesting period before reaching age limit 2 months    
Restricted Shares [Member] | Age 65 [Member] | Executives [Member]      
Restricted and Performance Stock Grants [Abstract]      
Vesting percentage 100.00%    
Vesting period before reaching age limit 2 months    
Performance-based Shares [Member]      
Restricted and Performance Stock Grants [Abstract]      
Measuring period for performance-based shares 3 years    
Performance-based Shares [Member] | Minimum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Expiration of vesting period 3 years    
Restricted and Performance-Based Shares [Member]      
Restricted and performance-based stock, shares [Roll Forward]      
Beginning of period (in shares) 839,686    
Granted (in shares) 211,375    
Vested (in shares) (64,298)    
Forfeited (in shares) (12,125)    
End of period (in shares) 974,638    
Restricted and performance-based stock, weighted average grant date fair value per share [Roll Forward]      
Beginning of period (in dollars per share) | $ / shares $ 34.77    
Granted (in dollars per share) | $ / shares 38.49    
Vested (in dollars per share) | $ / shares 31.60    
Forfeited (in dollars per share) | $ / shares 39.21    
End of period (in dollars per share) | $ / shares $ 35.61    
Additional Disclosures [Abstract]      
Compensation expense, gross | $ $ 6,800 5,700  
Compensation expense, net of tax | $ 5,100 $ 4,300  
Unamortized compensation expense | $ $ 18,300    
Restricted and Performance-Based Shares [Member] | Employees [Member]      
Additional Disclosures [Abstract]      
Weighted average period of recognition for unrecognized compensation expense 3 years 10 months 24 days    
Restricted and Performance-Based Shares [Member] | Directors [Member]      
Additional Disclosures [Abstract]      
Weighted average period of recognition for unrecognized compensation expense 7 months 6 days    
Restricted and Performance-Based Shares [Member] | Executives and Directors [Member] | Minimum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Post vesting holding period for restricted and performance shares issued 1 year    
Restricted and Performance-Based Shares [Member] | Executives and Directors [Member] | Maximum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Post vesting holding period for restricted and performance shares issued 2 years    
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     950,000
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member] | Minimum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     1,100,000
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member] | Maximum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     2,050,000
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member] | Non-employee Directors [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     100,000
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member] | Non-employee Directors [Member] | Minimum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     250,000
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member] | Non-employee Directors [Member] | Maximum [Member]      
Restricted and Performance Stock Grants [Abstract]      
Shares authorized for issuance (in shares)     350,000