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Stock Incentive Plans - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
May 21, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Award vesting period                 3 years      
Stock-based compensation cost $ 2.4 $ 3.1 $ 2.2 $ 1.9 $ 1.8 $ 2.0 $ 2.5 $ 1.9 $ 9.6 $ 8.2 $ 5.0  
Total unrecognized compensation cost related to non-vested share-based compensation arrangements $ 10.5               $ 10.5      
Expected period to recognize total unrecognized compensation cost related to non-vested share-based compensation arrangements                 1 year 4 months 24 days      
2019 LTIP                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Number of shares authorized (in shares)                       4,236,959
Shares available for issuance (in shares) 3,550,881               3,550,881      
2010 LTIP                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Shares available for issuance (in shares) 0               0      
Shares cliff vest percentage                 33.30%      
2007 LTIP                        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                        
Shares available for issuance (in shares) 0               0      
Shares cliff vest percentage                 33.30%      
Remaining period following first vesting commencement date                 2 years