Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Expense and Related Tax Effects (Details)

v3.20.4
Stock-Based Compensation - Expense and Related Tax Effects (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Payment Arrangement [Abstract]      
Stock-based compensation expense $ 2.7 $ 1.2 $ 4.7
Income tax benefit $ 0.0 $ 0.0 $ 1.1