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Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($)		3 Months Ended	12 Months Ended
	Jul. 12, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill			$ 534,700,000	$ 531,400,000
Period increase (decrease) in goodwill			3,300,000
Impairment of goodwill		$ (114,400,000)	0	(114,400,000)	$ 0
Accumulated goodwill impairment			241,000,000	241,000,000
Addaero Manufacturing [Member]
Goodwill [Line Items]
Goodwill			6,000,000
Payments to Acquire Businesses, Gross	$ 10,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles			2,000,000
High Performance Materials & Components
Goodwill [Line Items]
Goodwill			534,700,000
Impairment of goodwill			0	$ (114,400,000)	$ 0
Goodwill, Foreign Currency Translation Gain (Loss)			$ (2,700,000)
High Performance Materials & Components | First Reporting Unit [Member]
Goodwill [Line Items]
Percentage of fair value in excess of carrying value					12.00%

X

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The amount of identifiable intangible assets recognized as of the acquisition date.

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