Acquisitions (Details) £ in Millions, $ in Millions					3 Months Ended		6 Months Ended
	Nov. 01, 2017 USD ($)	Jul. 03, 2017 USD ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2017 GBP (£)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Jan. 31, 2017 GBP (£)
Acquisitions
Total consideration							$ 20.0
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					$ 1,448.0		1,448.0		$ 1,452.1
Aggregate cash purchase price, net of cash acquired							19.3	$ 225.9
Accella Performance Materials
Acquisitions
Percentage of ownership interest acquired	100.00%
Total consideration	$ 671.4
Contribution to net sales since acquisition					121.9		228.4
Contribution to EBIT since acquisition					1.7		0.1
Unaudited pro forma revenue						$ 1,092.6		1,953.0
Unaudited pro forma income from continuing operations						90.3		140.9
Additional depreciation and amortization related to fair value adjustments						$ 2.7		$ 6.8
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables					66.8		66.8
Inventories					47.5		47.5
Definite-lived intangible assets					240.0		240.0
Other long-term assets					15.6		15.6
Accounts payable					45.5		45.5
Deferred income tax liabilities					83.5		83.5
Goodwill					380.8		380.8
Gross contractual accounts receivable acquired	68.5
Receivables not expected to be acquired	1.7
Goodwill deductible for tax purposes	38.5
Indemnification asset	25.0
Accella Performance Materials | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 66.0
Accella Performance Materials | Acquired Technology | Minimum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	3 years
Accella Performance Materials | Acquired Technology | Maximum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	14 years
Accella Performance Materials | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 146.0
Accella Performance Materials | Customer relationships | Minimum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	9 years
Accella Performance Materials | Customer relationships | Maximum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	12 years
Accella Performance Materials | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 28.0
Accella Performance Materials | Trade names | Minimum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	4 years
Accella Performance Materials | Trade names | Maximum
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	14 years
Drexel Metals, Inc.
Acquisitions
Percentage of ownership interest acquired		100.00%
Contribution to net sales since acquisition					19.0		31.0
Contribution to EBIT since acquisition					1.8		2.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables		$ 5.3
Inventories		8.8
Definite-lived intangible assets		19.0
Accounts payable		5.8
Deferred income tax liabilities		10.8
Goodwill		26.9
Goodwill deductible for tax purposes		$ 0.0
Useful life of finite lived intangible assets		9 years
Aggregate cash purchase price, net of cash acquired		$ 55.8
Indefinite-lived intangible assets		$ 10.4
Arbo
Acquisitions
Percentage of ownership interest acquired			100.00%							100.00%
Contribution to net sales since acquisition					4.9		9.4
Contribution to EBIT since acquisition					$ 0.3		$ 0.5
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables			$ 1.5
Inventories			2.1
Definite-lived intangible assets			2.2
Accounts payable			1.4
Deferred income tax liabilities			1.4
Goodwill			4.7
Goodwill deductible for tax purposes			1.3
Aggregate cash purchase price, net of cash acquired			11.5	£ 9.1
Indefinite-lived intangible assets			1.6
Contingent consideration			$ 2.5							£ 2.0
Arbo | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets			15 years	15 years