Dispositions and Special Charges - Reconciliation of Pretax Loss on Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Net sales	$ 0.0	$ 0.0	$ 0.0	$ 117.0
Cost of sales	0.0	0.0	0.0	102.9
Gross profit	0.0	0.0	0.0	14.1
Selling, distribution & administrative expenses	(0.4)	1.4	0.0	20.0
Special charges	0.0	4.4	(0.7)	28.3
Operating income (loss) from discontinued operations	0.4	(5.8)	0.7	(34.2)
Interest and other (income) expenses, net	(0.1)	0.2	(0.3)	0.5
Income (loss) from discontinued operations before income taxes	0.5	(6.0)	1.0	(34.7)
Provision (benefit) for income taxes	0.1	(0.5)	0.2	(0.4)
Net income (loss) from discontinued operations	$ 0.4	$ (5.5)	$ 0.8	$ (34.3)
Net income (loss) per share – basic (in dollars per share)	$ 0.01	$ (0.15)	$ 0.02	$ (0.93)
Net income (loss) per share – diluted (in dollars per share)	$ 0.01	$ (0.15)	$ 0.02	$ (0.92)