Goodwill and Purchased Intangible Assets - Schedule of Gross Goodwill and Other Purchased Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Changes in the carrying amount of gross goodwill and other purchased intangibles
Balance at the beginning of the period	$ 280.4	$ 142.3
Amortization expense	(6.9)	(6.9)
Additions		145.1
Currency translation adjustments and other	4.3	(0.1)
Balance at the end of the period	277.8	280.4
Composite Materials
Changes in the carrying amount of gross goodwill and other purchased intangibles
Balance at the beginning of the period	96.2	98.2
Amortization expense	(1.9)	(2.0)
Currency translation adjustments and other	4.4
Balance at the end of the period	98.7	96.2
Engineered Products
Changes in the carrying amount of gross goodwill and other purchased intangibles
Balance at the beginning of the period	184.2	44.1
Amortization expense	(5.0)	(4.9)
Additions		145.1
Currency translation adjustments and other	(0.1)	(0.1)
Balance at the end of the period	$ 179.1	$ 184.2