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Stock-Based Compensation - Narrative (Details) - USD ($)
12 Months Ended 20 Months Ended 36 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2017
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2016
Mar. 07, 2018
Mar. 06, 2018
Restricted Stock Units                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Share-based compensation arrangement by share-based payment award, equity instruments other than options, authorized in period (in shares) 37,235                  
Restricted stock units awarded (in shares) 37,235 57,089 22,000              
Stock-based compensation expense $ 1,100,000 $ 900,000 $ 900,000              
Vested (in shares) 78,469 173,240 26,399              
Weighted average remaining recognition period of unrecognized stock-based compensation costs (in years) 1 year 9 months 18 days 2 years 3 months 18 days 2 years 1 month 6 days              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 33.61 $ 35.28 $ 18.25              
Performance Shares                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Restricted stock units awarded (in shares) 173,594 55,640 29,494              
Vesting period 3 years 3 years       3 years        
Stock-based compensation expense $ 3,300,000 $ 1,400,000 $ 1,300,000              
Vested (in shares) 43,845 66,657 61,919              
Weighted average remaining recognition period of unrecognized stock-based compensation costs (in years) 1 year 9 months 18 days                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 33.80 $ 36.49 $ 29.51              
Performance Shares | Minimum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period 3 years                  
Performance Shares | Maximum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period 5 years                  
Unrecognized compensation costs related to unvested options $ 11,300,000         $ 11,300,000        
Performance Shares Adjustments                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Restricted stock units awarded (in shares) 48,632 45,075 59,091              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 36.05 $ 35.86 $ 26.07              
Long-term incentive plan                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Maximum number of shares of common stock available for awards (in shares)                 3,775,000 2,975,000
Shares remaining available for awards (in shares) 746,816         746,816        
Long-term incentive plan | Stock Options                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Granted (in shares)   0 0              
Stock-based compensation expense not recognized by employer   $ 0 $ 0   $ 0   $ 0      
Executive Officer | Restricted Stock Units                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Restricted stock units awarded (in shares)   0                
Vesting period 3 years                  
Executive Officer | Performance Shares                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period 3 years 3 years 3 years 3 years 3 years   3 years 3 years    
Stock-based compensation expense   $ 200,000 $ 200,000              
Shares recognized in period (in shares)   15,497 7,529              
Vested (in shares)   51,160 54,390              
Executive Officer | Long-term incentive plan | Retirement eligibility                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vested (in shares) 3,631                  
Executive Officer | Long-term incentive plan | Performance Shares                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period 3 years                  
Vested (in shares) 40,214                  
Tranche 1 | Executive Officer | Restricted Stock Units                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Restricted stock units awarded (in shares)   48,663                
Vesting period 3 years                  
Tranche 1 | Executive Officer | Restricted Stock Units | Minimum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period   3 years                
Tranche 1 | Executive Officer | Restricted Stock Units | Maximum                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Vesting period   5 years                
Tranche 2 | Executive Officer | Restricted Stock Units                    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                    
Restricted stock units awarded (in shares)   8,426                
Vesting period 5 years