Acquisitions - Summary of Assets Acquired and Liabilities Assumed Coldenhove Acquisition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Nov. 01, 2017
Assets Acquired
Acquired goodwill (a)	$ 84.0			$ 84.0	$ 85.3	$ 70.4
Liabilities Assumed
Adjustment to goodwill				1.1
Acquisition related adjustments	(0.8)	$ (3.1)		3.9	0.0	$ 0.0
W.A. Sanders Coldenhove Holding B.V.
Assets Acquired
Cash and cash equivalents					4.9
Accounts receivable					4.7
Inventories (a)					12.7
Deferred income taxes					0.4
Prepaid and other current assets					0.2
Property, plant and equipment (a)					31.2
Non-amortizable intangible assets					1.2
Amortizable intangible assets					4.7
Acquired goodwill (a)					10.0
Other assets					0.1
Total assets acquired					70.1
Liabilities Assumed
Accounts payable					4.1
Accrued expenses					5.4
Contingent liability (b)	0.8			0.8	2.3		$ 2.3
Deferred income taxes (a)					3.5
Noncurrent employee benefits					4.9
Long-term debt					1.8
Other noncurrent obligations					0.1
Total liabilities assumed					22.1
Net assets acquired					$ 48.0
Adjustment to inventory and fixed assets			$ 1.5
Adjustment to goodwill			$ 1.1
Separately recognized transactions	$ 2.4			2.4
Acquisition related adjustments				$ 3.9