Segment Information - Schedule of Operating Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Total sales	$ 547.5	$ 491.3	$ 1,087.6	$ 970.1
Operating income	96.5	89.7	178.9	168.3
Depreciation and amortization	29.8	25.1	59.6	49.5
Stock-based compensation	2.1	2.4	12.0	13.3
Accrual basis additions to capital expenditures	44.7	77.2	90.0	170.1
Corporate & Other and Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	(20.3)	(15.1)	(39.5)	(32.2)
Operating income	(12.5)	(14.5)	(31.0)	(30.8)
Stock-based compensation	1.1	1.0	6.7	7.8
Composite Materials
Segment Reporting Information [Line Items]
Total sales	445.8	397.3	890.4	784.8
Composite Materials | Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	20.3	15.1	39.5	32.2
Composite Materials | Operating Segments
Segment Reporting Information [Line Items]
Total sales	466.1	412.4	929.9	817.0
Operating income	93.1	92.1	184.1	174.0
Depreciation and amortization	27.5	23.3	55.0	45.8
Stock-based compensation	0.9	1.2	4.5	4.6
Accrual basis additions to capital expenditures	43.4	74.5	88.7	161.1
Engineered Products
Segment Reporting Information [Line Items]
Total sales	101.7	94.0	197.2	185.3
Engineered Products | Operating Segments
Segment Reporting Information [Line Items]
Total sales	101.7	94.0	197.2	185.3
Operating income	15.9	12.1	25.8	25.1
Depreciation and amortization	2.3	1.8	4.6	3.7
Stock-based compensation	0.1	0.2	0.8	0.9
Accrual basis additions to capital expenditures	$ 1.3	$ 2.7	$ 1.3	$ 9.0