XML 56 R44.htm IDEA: XBRL DOCUMENT v3.21.1
Net Income Per Share of Class A and Class B Common Stock (Earnings Per Share Reconciliation) (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]    
Weighted average common shares outstanding - basic (in shares) 26.6 23.3
Weighted average common shares outstanding - diluted (in shares) 26.9 23.5
Net income per common share - basic (in dollars per share) $ 5.86 $ 1.99
Net income per common share - diluted (in dollars per share) $ 5.81 $ 1.97
Class A common stock    
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]    
Net income applicable to common stockholders - basic $ 155.8 $ 45.0
Reallocation of net income due to conversion of Class B to Class A common shares outstanding 0.0 0.2
Conversion of Class B common shares into Class A common shares 0.4 1.0
Net income applicable to common stockholders - diluted $ 156.2 $ 46.2
Weighted average common shares outstanding - basic (in shares) 26.6 22.7
Conversion of Class B common shares into Class A common shares (in shares) 0.1 0.6
Effect of employee stock purchases and restricted stock units on weighted average common shares (in shares) 0.2 0.2
Weighted average common shares outstanding - diluted (in shares) 26.9 23.5
Net income per common share - basic (in dollars per share) $ 5.86 $ 1.99
Net income per common share - diluted (in dollars per share) $ 5.81 $ 1.97
Class B common stock    
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]    
Net income applicable to common stockholders - basic $ 0.4 $ 1.2
Reallocation of net income due to conversion of Class B to Class A common shares outstanding 0.0 0.0
Conversion of Class B common shares into Class A common shares 0.0 0.0
Net income applicable to common stockholders - diluted $ 0.4 $ 1.2
Weighted average common shares outstanding - basic (in shares) 0.1 0.6
Conversion of Class B common shares into Class A common shares (in shares) 0.0 0.0
Effect of employee stock purchases and restricted stock units on weighted average common shares (in shares) 0.0 0.0
Weighted average common shares outstanding - diluted (in shares) 0.1 0.6
Net income per common share - basic (in dollars per share) $ 5.86 $ 1.99
Net income per common share - diluted (in dollars per share) $ 5.81 $ 1.97