Segment Information - Schedule of Operating Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total sales	$ 310.3	$ 541.0
Other operating expense	12.1	14.7
Operating income	(10.2)	65.7
Depreciation and amortization	34.5	35.5
Stock-based compensation	9.0	14.4
Accrual basis additions to capital expenditures	4.0	21.9
Corporate & Other and Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	(13.8)	(25.3)
Other operating expense	0.1	13.8
Operating income	(22.3)	(32.3)
Stock-based compensation	8.2	8.5
Composite Materials
Segment Reporting Information [Line Items]
Total sales	237.2	438.5
Composite Materials | Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	13.2	24.8
Composite Materials | Operating Segments
Segment Reporting Information [Line Items]
Total sales	250.4	463.3
Other operating expense	12.7	0.6
Operating income	7.4	91.5
Depreciation and amortization	30.8	31.8
Stock-based compensation	0.6	4.7
Accrual basis additions to capital expenditures	3.6	20.2
Engineered Products
Segment Reporting Information [Line Items]
Total sales	73.1	102.5
Engineered Products | Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	0.6	0.5
Engineered Products | Operating Segments
Segment Reporting Information [Line Items]
Total sales	73.7	103.0
Other operating expense	(0.7)	0.3
Operating income	4.7	6.5
Depreciation and amortization	3.7	3.7
Stock-based compensation	0.2	1.2
Accrual basis additions to capital expenditures	$ 0.4	$ 1.7