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Employee Stock Purchase Plan, Stock Options and Warrants - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Compensation cost not yet recognized $ 28.6    
Compensation cost not yet recognized, period of recognition 3 years    
Options granted in period (in shares) 1,200,000 692,000 1,300,000
Fair value of options, net of forfeitures $ 20.9 $ 11.1 $ 12.4
Options granted in period, weighted average grant date fair value (in dollars per share) $ 16.78 $ 16.05 $ 9.57
2018 Incentive Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for grant (in shares) 1,714,323    
2018 Incentive Plan | Stock Options      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Option contractual life 7 years    
2018 Incentive Plan | Stock Options | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 3 years    
2018 Incentive Plan | Stock Options | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 5 years    
ESPP      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Shares available for grant (in shares) 69,877    
Purchase price for ESPP, percent of market price 95.00%