Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts Receivable, allowances (in dollars)	$ 4.2	$ 4.2
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	139,531,171	138,601,327
Common stock, shares outstanding	138,491,860	138,562,016
Treasury stock, shares	51,390	0