XML 130 R114.htm IDEA: XBRL DOCUMENT v3.21.1
Stock-Based Compensation Plans - Restricted Stock Units Narrative (Details) - Restricted Stock Units (RSUs)
$ in Millions
12 Months Ended
Dec. 31, 2020
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 4 years
Compensation expense for stock options $ 7.4
Unrecognized compensation cost related to unvested options $ 41.8
Unrecognized compensation cost related to unvested options, weighted-average period of recognition 3 years 5 months 12 days