Income Per Common Share Computations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net income	$ 8.7	$ 4.2	$ 81.3	$ 57.7
Participating Securities, Distributed and Undistributed Earnings (Loss), Basic	(0.1)	0.0	(1.4)	(0.9)
Income (Loss) from Continuing Operations, Basic	8.6	4.2	79.9	56.8
Net Income (Loss) Available to Common Stockholders, Diluted	$ 8.7	$ 4.2	$ 81.3	$ 57.7
Earnings Per Share, Basic and Diluted [Abstract]
Basic	16.4	17.3	16.5	17.3
Plus dilutive effect of stock options and restricted stock	0.2	0.2	0.2	0.1
Plus dilutive effect of participating securities	0.3	0.3	0.3	0.3
Diluted	16.9	17.8	17.0	17.7
Earnings Per Share, Diluted [Abstract]
Basic	$ 0.52	$ 0.24	$ 4.85	$ 3.28
Diluted	$ 0.52	$ 0.24	$ 4.79	$ 3.26