Segment Information - Schedule of Operating Segment Reporting Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Sales	$ 295,800,000	$ 286,900,000	$ 378,700,000	$ 541,000,000.0	$ 564,300,000	$ 572,500,000	$ 609,000,000.0	$ 609,900,000	$ 1,502,400,000	$ 2,355,700,000	$ 2,189,100,000
Operating income (loss)	(20,400,000)	$ (37,600,000)	$ 6,400,000	$ 65,700,000	97,400,000	$ 109,900,000	$ 115,100,000	$ 102,800,000	14,100,000	425,200,000	371,200,000
Depreciation and amortization									140,900,000	141,700,000	123,100,000
Equity in earnings from affiliated companies									(1,600,000)	3,700,000	5,600,000
Other operating expense									57,900,000	0	7,700,000
Segment assets	2,917,800,000				3,128,600,000				2,917,800,000	3,128,600,000	2,824,100,000
Investments in affiliated companies	44,700,000				46,500,000				44,700,000	46,500,000	48,700,000
Accrual basis additions to property, plant and equipment									42,500,000	191,000,000.0	179,100,000
Corporate & Other and Intersegment Elimination
Segment Reporting Information [Line Items]
Sales									(56,400,000)	(84,200,000)	(74,700,000)
Operating income (loss)									(56,000,000.0)	(58,100,000)	(53,200,000)
Depreciation and amortization									100,000	100,000	100,000
Equity in earnings from affiliated companies									(200,000)	(300,000)
Other operating expense									16,000,000.0
Segment assets	61,700,000				(6,200,000)				61,700,000	(6,200,000)	49,300,000
Investments in affiliated companies	7,700,000				8,200,000				7,700,000	8,200,000	14,200,000
Composite Materials
Segment Reporting Information [Line Items]
Sales									1,185,900,000	1,863,100,000	1,770,500,000
Composite Materials | Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)									60,700,000	411,300,000	373,800,000
Depreciation and amortization									125,500,000	126,500,000	113,900,000
Equity in earnings from affiliated companies									(300,000)	(300,000)
Other operating expense									32,100,000
Segment assets	2,382,300,000				2,669,600,000				2,382,300,000	2,669,600,000	2,501,900,000
Investments in affiliated companies	2,000,000.0				2,200,000				2,000,000.0	2,200,000	2,400,000
Accrual basis additions to property, plant and equipment									38,600,000	185,800,000	173,500,000
Composite Materials | Intersegment Elimination
Segment Reporting Information [Line Items]
Sales									53,900,000	83,400,000	74,600,000
Engineered Products
Segment Reporting Information [Line Items]
Sales									316,500,000	492,600,000	418,600,000
Engineered Products | Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)									9,400,000	72,000,000.0	50,600,000
Depreciation and amortization									15,300,000	15,100,000	9,100,000
Equity in earnings from affiliated companies									(1,100,000)	4,300,000	5,600,000
Other operating expense									9,800,000		7,700,000
Segment assets	473,800,000				465,200,000				473,800,000	465,200,000	272,900,000
Investments in affiliated companies	$ 35,000,000.0				$ 36,100,000				35,000,000.0	36,100,000	32,100,000
Accrual basis additions to property, plant and equipment									3,900,000	5,200,000	5,600,000
Engineered Products | Intersegment Elimination
Segment Reporting Information [Line Items]
Sales									$ 2,500,000	$ 800,000	$ 100,000