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Stock-Based Compensation Plans - Stock Options Narrative (Details) - Stock options
$ in Millions
12 Months Ended
Dec. 31, 2020
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting percentage per year 25.00%
Vesting period 4 years
Contractual term 10 years
Compensation expense for stock options $ 5.6
Unrecognized compensation cost related to unvested options $ 21.6
Unrecognized compensation cost related to unvested options, weighted-average period of recognition 3 years 2 months 8 days