Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Current assets
Allowance for doubtful accounts	$ 10.0	$ 5.8
Stockholders' equity
Treasury Stock, shares	0.8	0.9
Preferred Stock [Member]
Stockholders' equity
Preferred Stock, par value per share	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10.0	10.0
Preferred Stock, shares issued	0.0	0.0
Preferred Stock, shares outstanding	0.0	0.0
Perpetual Preferred Stock [Member]
Stockholders' equity
Preferred Stock, shares authorized	0.8	0.8
Preferred Stock, shares issued	0.0	0.0
Preferred Stock, shares outstanding	0.0	0.0
Series Common Stock [Member]
Stockholders' equity
Common Stock, par value per share	$ 0.01	$ 0.01
Common Stock, shares authorized	40.0	40.0
Common Stock, shares issued	0.0	0.0
Common Stock, shares outstanding	0.0	0.0
Common Stock [Member]
Stockholders' equity
Common Stock, par value per share	$ 0.01	$ 0.01
Common Stock, shares authorized	53.3	53.3
Common Stock, shares issued	19.3	19.0
Common Stock, shares outstanding	18.5	18.1