CONDENSED CONSOLIDATED BALANCE SHEET (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Current assets
Trade receivables, allowance (in dollars)	$ 11.2	$ 9.5
Stockholders’ equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common authorized (in shares)	300,000,000.0	300,000,000.0
Common issued (in shares)	83,400,000	82,900,000
Treasury stock (in shares)	14,200,000	14,300,000