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Stock-Based Compensation Plans (Details)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2021
USD ($)
Type
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Restricted Stock and Performance Share Grants [Abstract]      
Number of types of restricted stock | Type 2    
Restricted Shares [Member] | Minimum [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Expiration of vesting period 3 years    
Restricted Shares [Member] | Employees [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Estimated forfeitures 5.00%    
Restricted Shares [Member] | Executives [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Estimated forfeitures 0.00%    
Restricted Shares [Member] | Directors [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Estimated forfeitures 0.00%    
Restricted Shares [Member] | Age 60 [Member] | Executives [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Vesting percentage 25.00%    
Vesting period before reaching age limit 2 months    
Restricted Shares [Member] | Age 63 [Member] | Executives [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Vesting percentage 25.00%    
Vesting period before reaching age limit 2 months    
Restricted Shares [Member] | Age 65 [Member] | Executives [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Vesting percentage 100.00%    
Vesting period before reaching age limit 2 months    
Performance-Based Shares [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Measuring period for performance-based shares 3 years    
Restricted and performance-based stock, shares [Roll Forward]      
Forfeited (in shares)   (50,250)  
Performance-Based Shares [Member] | Minimum [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Expiration of vesting period 3 years    
Restricted and Performance-Based Shares [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Unamortized compensation expense | $ $ 16.6 $ 15.2  
Restricted and performance-based stock, shares [Roll Forward]      
Beginning of period (in shares) 839,686 852,540  
Granted (in shares) 211,815 208,200  
Vested (in shares) (227,682) (161,054)  
Forfeited (in shares) (16,800) (60,000) [1]  
End of period (in shares) 807,019 839,686 852,540
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 $ 35.26  
Granted (in dollars per share) | $ / shares 38.51 38.21  
Vested (in dollars per share) | $ / shares 36.10 39.23  
Forfeited (in dollars per share) | $ / shares 39.39 42.25  
End of period (in dollars per share) | $ / shares $ 34.92 $ 34.77 $ 35.26
Weighted-average grant date fair value | $ $ 28.2 $ 29.2 $ 30.1
Restricted and Performance-Based Shares [Member] | Employees [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Weighted average period of recognition for unrecognized compensation expense 4 years 8 months 12 days 4 years 7 months 6 days  
Restricted and Performance-Based Shares [Member] | Directors [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Weighted average period of recognition for unrecognized compensation expense 4 months 24 days 3 months 18 days  
Restricted and Performance-Based Shares [Member] | Executives and Directors [Member] | Minimum [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Holding period for restricted and performance shares issued 1 year    
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 Stock and Performance Share Grants [Abstract]      
Holding period for restricted and performance shares issued 2 years    
Post vesting holding period for restricted and performance shares issued 2 years    
2016 Omnibus Incentive Plan [Member] | Restricted Shares [Member]      
Restricted and performance-based stock, shares [Roll Forward]      
Granted (in shares) 159,565    
2016 Omnibus Incentive Plan [Member] | Performance-Based Shares [Member]      
Restricted and performance-based stock, shares [Roll Forward]      
Granted (in shares) 52,250    
2016 Omnibus Incentive Plan [Member] | Restricted and Performance-Based Shares [Member]      
Restricted Stock and Performance Share Grants [Abstract]      
Restricted and performance-based stock grants issued, net of forfeitures (in shares) 1,121,445    
Common stock available for future grants (in shares) 928,555    
2016 Omnibus Incentive Plan [Member] | Employees and Directors [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]      
Shares authorized for issuance (in shares) 2,050,000    
2016 Omnibus Incentive Plan [Member] | Nonemployee Directors [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Abstract]      
Shares authorized for issuance (in shares) 350,000    
[1] Due to the lack of achievement of performance targets, performance-based shares forfeited in the year ended December 31, 2020 were 50,250 shares.