Segment Information - Schedule of Operating Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total sales	$ 540.5	$ 491.5	$ 1,628.1	$ 1,461.6
Operating income	96.5	89.1	275.4	257.4
Depreciation and amortization	31.2	26.8	90.8	76.3
Stock-based compensation	2.0	2.2	14.0	15.5
Accrual basis additions to capital expenditures	43.5	47.9	133.5	218.0
Corporate & Other and Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	(17.2)	(16.4)	(56.7)	(48.6)
Operating income	(11.5)	(13.0)	(42.5)	(43.8)
Depreciation and amortization		0.1	0.1	0.1
Stock-based compensation	0.6	1.0	7.3	8.8
Composite Materials
Segment Reporting Information [Line Items]
Total sales	432.8	398.9	1,323.2	1,183.7
Composite Materials | Intersegment Elimination
Segment Reporting Information [Line Items]
Total sales	17.2	16.4	56.7	48.6
Composite Materials | Operating Segments
Segment Reporting Information [Line Items]
Total sales	450.0	415.3	1,379.9	1,232.3
Operating income	92.5	90.0	276.6	264.0
Depreciation and amortization	28.9	24.8	83.9	70.6
Stock-based compensation	1.2	1.1	5.7	5.7
Accrual basis additions to capital expenditures	41.4	47.4	130.1	208.5
Engineered Products
Segment Reporting Information [Line Items]
Total sales	107.7	92.6	304.9	277.9
Engineered Products | Operating Segments
Segment Reporting Information [Line Items]
Total sales	107.7	92.6	304.9	277.9
Operating income	15.5	12.1	41.3	37.2
Depreciation and amortization	2.3	1.9	6.8	5.6
Stock-based compensation	0.2	0.1	1.0	1.0
Accrual basis additions to capital expenditures	$ 2.1	$ 0.5	$ 3.4	$ 9.5