XML 84 R74.htm IDEA: XBRL DOCUMENT v3.21.2
Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2021
Mar. 31, 2021
Jun. 30, 2020
Mar. 31, 2020
Jun. 30, 2021
Jun. 30, 2020
Numerator:            
Net income $ 146.5 $ 122.3 $ 73.7 $ 69.1 $ 268.8 $ 142.8
Denominator:            
Shares used in net income per common share – basic 55.4   55.1   55.3 55.0
Effect of dilutive securities:            
Restricted stock units and stock appreciation rights 0.3   0.2   0.3 0.3
Shares used in net income per common share – diluted 55.7   55.3   55.6 55.3
Net income per common share:            
Basic $ 2.64   $ 1.34   $ 4.86 $ 2.60
Diluted $ 2.63   $ 1.33   $ 4.83 $ 2.58