Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Accounts Receivable, allowances (in dollars)	$ 9.8	$ 10.3
Preferred stock authorized (in shares)	3,500,000	3,500,000
Par value of preferred stock per share (in dollars per share)	$ 0.01	$ 0.01
Preferred stock outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	75,000,000	75,000,000
Common stock, shares issued (in shares)	40,793,983	40,793,983
Common stock, shares outstanding (in shares)	35,349,046	35,588,833
Treasury stock (in shares)	5,444,937	5,205,150