Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Trade accounts receivable, allowance	$ 6.5	$ 5.8
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	10,000,000	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	300,000,000	300,000,000
Common stock, outstanding (in shares)	72,685,612	72,176,324