Discontinued Operations - Loss From Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-cash asset impairments									$ 0.3	$ 0.8	$ 1.5
Loss from discontinued operations, net of tax	$ (0.4)	$ (27.8)	$ (83.7)	$ (42.8)	$ (119.9)	$ (4.3)	$ (3.5)	$ (2.9)	(154.7)	(130.6)	(17.6)
Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									124.3	214.4	205.7
Cost of sales									94.9	166.5	166.3
Selling, general and administrative expenses									35.1	56.5	57.2
Restructuring and other similar charges									0.0	4.7	5.5
Amortization of intangible assets									0.3	1.4	1.1
Non-cash asset impairments			$ 82.0	$ 44.0					126.0	111.2	0.0
Loss on sale of discontinued operations		$ 19.7							22.5	0.0	0.0
Other non-operating expenses, net									3.2	4.7	0.9
Loss from discontinued operations before income tax									(157.7)	(130.6)	(25.3)
Income tax benefit									3.0	0.0	7.7
Loss from discontinued operations, net of tax									$ (154.7)	$ (130.6)	$ (17.6)