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Stock-Based Compensation (Details) - Long Term Incentive Plan
$ / shares in Units, $ in Millions
6 Months Ended
Jun. 30, 2017
USD ($)
$ / shares
shares
Performance Shares  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares granted (in shares) 32,680
Weighted-average grant date fair value (in dollars per share) | $ / shares $ 57.05
Unrecognized compensation costs | $ $ 2.8
Performance Shares | Minimum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Conversion ratio, percent of target 0.00%
Performance Shares | Maximum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Conversion ratio, percent of target 200.00%
Award vesting period 3 years
Restricted Stock Units (RSUs)  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Award vesting period 4 years
Unrecognized compensation costs | $ $ 3.3
Number of RSUs granted in period (in shares) 28,488
Weighted-average grant date fair value (in dollars per share) | $ / shares $ 59.78
Number of common shares to be issued per award (in shares) 1
Unrecognized compensation cost, period for recognition through 2021