XML 135 R119.htm IDEA: XBRL DOCUMENT v3.20.4
Net Income Per Share - Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Numerator:                      
Net income $ 115.6 $ 91.7 $ 73.7 $ 69.1 $ 42.8 $ 47.4 $ 37.7 $ 12.5 $ 350.1 $ 140.4 $ 392.9
Denominator:                      
Shares used in net income per common share – basic                 55,095,000 54,711,000 54,406,000
Effect of dilutive securities                 255,000 400,000 586,000
Shares used in net income per common share – diluted                 55,350,000 55,111,000 54,992,000
Net income per common share:                      
Basic $ 2.10 $ 1.66 $ 1.34 $ 1.26 $ 0.78 $ 0.86 $ 0.69 $ 0.23 $ 6.36 $ 2.57 $ 7.22
Diluted $ 2.08 $ 1.66 $ 1.33 $ 1.25 $ 0.77 $ 0.86 $ 0.69 $ 0.23 $ 6.33 $ 2.55 $ 7.14