Acquisitions (Details) £ in Millions, SFr in Millions, $ in Millions									3 Months Ended		6 Months Ended	9 Months Ended			10 Months Ended
	Jul. 03, 2017 USD ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2017 GBP (£)	Jan. 09, 2017 USD ($)	Oct. 03, 2016 USD ($)	Jun. 10, 2016 USD ($)	Feb. 19, 2016 USD ($)	Feb. 19, 2016 CHF (SFr)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Mar. 31, 2017 USD ($)	Jan. 31, 2017 GBP (£)	Dec. 31, 2016 USD ($)	Feb. 19, 2016 CHF (SFr)	Oct. 31, 2014 USD ($)
Acquisitions
Aggregate cash purchase price, net of cash acquired													$ 280.0	$ 103.1
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill										$ 1,212.8		$ 1,212.8	1,212.8				$ 1,081.2
Accella Performance Materials | Forecast
Acquisitions
Definitive purchase agreement amount									$ 670.0
Drexel Metals, Inc.
Acquisitions
Percentage of ownership interest acquired					100.00%
Aggregate cash purchase price, net of cash acquired	$ 55.8
Contribution to net sales since acquisition										12.8			12.8
Contribution to EBIT since acquisition										(0.9)			(0.9)
Useful life of finite lived intangible assets	9 years
Goodwill deductible for tax purposes	$ 0.0
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables	5.3
Inventories	8.8
Definite-lived intangible assets	19.0
Indefinite-lived intangible assets	10.4
Accounts payable	(5.8)
Deferred income tax liabilities	(10.8)
Goodwill	$ 26.9
Arbo
Acquisitions
Percentage of ownership interest acquired		100.00%														100.00%
Aggregate cash purchase price, net of cash acquired		$ 11.5	£ 9.1
Contribution to net sales since acquisition										4.1			10.3
Contribution to EBIT since acquisition										0.2			0.3
Contingent consideration		2.5														£ 2.0
Goodwill deductible for tax purposes		1.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables		1.5
Inventories		2.1
Definite-lived intangible assets		2.2
Indefinite-lived intangible assets		1.6
Accounts payable		(1.4)
Deferred income tax liabilities		(1.4)
Goodwill		$ 4.7
Arbo | Customer relationships
Acquisitions
Useful life of finite lived intangible assets		15 years	15 years
San Jamar
Acquisitions
Percentage of ownership interest acquired				100.00%
Contribution to net sales since acquisition										22.9			64.9
Contribution to EBIT since acquisition										2.8			3.5
Total consideration transferred												217.2
Goodwill deductible for tax purposes										5.0		5.0	5.0
Uncertain tax positions				$ 4.5
Indemnification asset				$ 3.6
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents										3.5		3.5	3.5
Receivables										9.1		9.1	9.1
Inventories										13.5		13.5	13.5
Prepaid expenses and other current assets										2.5		2.5	2.5
Property, plant and equipment										4.2		4.2	4.2
Definite-lived intangible assets										134.9		134.9	134.9
Indefinite-lived intangible assets										23.6		23.6	23.6
Other long-term assets										3.2		3.2	3.2
Accounts payable										(7.0)		(7.0)	(7.0)
Income tax payable										(0.5)		(0.5)	(0.5)
Accrued expenses										(5.2)		(5.2)	(5.2)
Other long-term liabilities										(4.5)		(4.5)	(4.5)
Deferred income tax liabilities										(49.6)		(49.6)	(49.6)
Total identifiable net assets										127.7		127.7	127.7
Goodwill										89.5		89.5	89.5
San Jamar | Customer relationships
Acquisitions
Useful life of finite lived intangible assets				13 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										97.8		97.8	97.8
San Jamar | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										36.4		36.4	36.4
San Jamar | Acquired Technology | Minimum
Acquisitions
Useful life of finite lived intangible assets				7 years
San Jamar | Acquired Technology | Maximum
Acquisitions
Useful life of finite lived intangible assets				10 years
San Jamar | Non-compete agreement
Acquisitions
Useful life of finite lived intangible assets				2 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										0.7		0.7	0.7
San Jamar | Preliminary Allocation
Acquisitions
Total consideration transferred				$ 217.2
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents				3.5
Receivables				9.1
Inventories				13.1
Prepaid expenses and other current assets				2.3
Property, plant and equipment				4.2
Definite-lived intangible assets				135.1
Indefinite-lived intangible assets				23.6
Other long-term assets				3.2
Accounts payable				(7.0)
Income tax payable				(0.5)
Accrued expenses				(4.3)
Other long-term liabilities				(4.8)
Deferred income tax liabilities				(47.2)
Total identifiable net assets				130.3
Goodwill				$ 86.9
San Jamar | Adjustment
Acquisitions
Total consideration transferred											$ 0.0
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables										0.0		0.0	0.0
Inventories										0.4		0.4	0.4
Prepaid expenses and other current assets										0.2		0.2	0.2
Definite-lived intangible assets										(0.2)		(0.2)	(0.2)
Other long-term assets										0.0		0.0	0.0
Accrued expenses										(0.9)		(0.9)	(0.9)
Other long-term liabilities										0.3		0.3	0.3
Deferred income tax liabilities										(2.4)		(2.4)	(2.4)
Total identifiable net assets										(2.6)		(2.6)	(2.6)
Goodwill										2.6		2.6	2.6
Star Aviation
Acquisitions
Percentage of ownership interest acquired					100.00%
Contribution to net sales since acquisition										11.8			27.8
Contribution to EBIT since acquisition										3.3			4.4
Total consideration transferred													82.7
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents										0.3		0.3	0.3
Receivables										5.8		5.8	5.8
Inventories										2.9		2.9	2.9
Prepaid expenses and other current assets										0.1		0.1	0.1
Property, plant and equipment										3.0		3.0	3.0
Definite-lived intangible assets										29.0		29.0	29.0
Accounts payable										(1.1)		(1.1)	(1.1)
Accrued expenses										(0.7)		(0.7)	(0.7)
Total identifiable net assets										39.3		39.3	39.3
Goodwill										43.4		43.4	43.4
Star Aviation | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										23.9		23.9	$ 23.9
Star Aviation | Customer relationships | Minimum
Acquisitions
Useful life of finite lived intangible assets													5 years
Star Aviation | Customer relationships | Maximum
Acquisitions
Useful life of finite lived intangible assets													10 years
Star Aviation | Acquired Technology
Acquisitions
Useful life of finite lived intangible assets													6 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										4.7		4.7	$ 4.7
Star Aviation | Non-compete agreement
Acquisitions
Useful life of finite lived intangible assets													5 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets										0.4		0.4	$ 0.4
Star Aviation | Preliminary Allocation
Acquisitions
Total consideration transferred					$ 82.7
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents					0.3
Receivables					5.9
Inventories					3.1
Prepaid expenses and other current assets					0.1
Property, plant and equipment					3.3
Definite-lived intangible assets					29.0
Accounts payable					(1.3)
Accrued expenses					(0.8)
Total identifiable net assets					39.6
Goodwill					$ 43.1
Star Aviation | Adjustment
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables										(0.1)		(0.1)	(0.1)
Inventories										(0.2)		(0.2)	(0.2)
Property, plant and equipment										(0.3)		(0.3)	(0.3)
Accounts payable										0.2		0.2	0.2
Accrued expenses										0.1		0.1	0.1
Total identifiable net assets										(0.3)		(0.3)	(0.3)
Goodwill										0.3		0.3	0.3
Micro-Coax
Acquisitions
Percentage of ownership interest acquired						100.00%
Contribution to net sales since acquisition										9.6			25.3
Contribution to EBIT since acquisition										1.9			(0.6)
Total consideration transferred															$ 96.6
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents											1.5
Receivables											6.3
Inventories											8.6
Prepaid expenses and other current assets											0.3
Property, plant and equipment											16.0
Definite-lived intangible assets											26.5
Indefinite-lived intangible assets											0.0
Other long-term assets											1.0
Accounts payable											(1.7)
Accrued expenses											(2.5)
Total identifiable net assets											56.0
Goodwill											40.6
Micro-Coax | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indefinite-lived intangible assets											0.9
Micro-Coax | Customer relationships
Acquisitions
Useful life of finite lived intangible assets															12 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets											14.5
Micro-Coax | Acquired Technology
Acquisitions
Useful life of finite lived intangible assets															7 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets											10.6
Micro-Coax | Preliminary Allocation
Acquisitions
Total consideration transferred						$ 97.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents						1.5
Receivables						6.3
Inventories						8.6
Prepaid expenses and other current assets						0.4
Property, plant and equipment						30.0
Definite-lived intangible assets						31.5
Indefinite-lived intangible assets						2.0
Other long-term assets						1.0
Accounts payable						(1.7)
Accrued expenses						(2.4)
Total identifiable net assets						77.2
Goodwill						$ 20.1
Micro-Coax | Preliminary Allocation | Trade names
Acquisitions
Useful life of finite lived intangible assets															10 years
Micro-Coax | Preliminary Allocation | Non-compete agreement
Acquisitions
Useful life of finite lived intangible assets															3 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets											0.5
Micro-Coax | Adjustment
Acquisitions
Total consideration transferred															$ (0.7)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Prepaid expenses and other current assets											(0.1)
Property, plant and equipment											(14.0)
Definite-lived intangible assets											(5.0)
Indefinite-lived intangible assets											(2.0)
Accrued expenses											(0.1)
Total identifiable net assets											(21.2)
Goodwill											$ 20.5
MS
Acquisitions
Percentage of ownership interest acquired							100.00%											100.00%
Contribution to net sales since acquisition										2.8			6.9
Contribution to EBIT since acquisition										(0.3)			(1.7)
Total consideration transferred							$ 12.4	SFr 12.3
Contingent consideration							4.3											SFr 4.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets							9.7
Indefinite-lived intangible assets							4.1
Deferred income tax liabilities							(2.2)
Goodwill							$ 2.9
MS | Customer relationships
Acquisitions
Useful life of finite lived intangible assets							10 years	10 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets							$ 1.4
MS | Acquired Technology
Acquisitions
Useful life of finite lived intangible assets							7 years	7 years
Recognized amounts of identifiable assets acquired and liabilities assumed:
Definite-lived intangible assets							$ 8.3
LHi Technology
Acquisitions
Indemnification asset										6.1		6.1	6.1						$ 8.7
Net change in indemnification asset										(4.6)
LHi Technology | Adjustment
Acquisitions
Contingent consideration										1.5		1.5	1.5	2.6
Indemnification asset										$ (1.5)		$ (1.5)	$ (1.5)	$ (2.6)