Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 Segment	Dec. 31, 2011	Dec. 31, 2010
Segment Information
Number of reporting segments									2
Segment information
Third-Party Sales	$ 387.3	$ 391.6	$ 399.2	$ 400.1	$ 355.3	$ 351.8	$ 353.7	$ 331.6	$ 1,578.2	$ 1,392.4	$ 1,173.6
Operating income (loss)	54.3	60.0	73.9	60.6	49.4	46.0	49.4	47.2	248.8	192.0	129.8
Depreciation									57.2	55.3	53.2
Equity in earnings from affiliated companies									0.7	1.6	0.5
Other (income) expense, net			(9.5)			2.7		(5.7)	(9.5)	(3.0)	3.5
Segment assets	1,603.1				1,376.1				1,603.1	1,376.1	1,258.1
Investments in affiliated companies	22.6				21.7				22.6	21.7	19.9
Accrual basis additions to property, plant and equipment									241.3	184.5	60.7
Composite Materials
Segment information
Third-Party Sales									1,230.9	1,074.5	904.5
Intersegment sales									56.8	53.8	38.7
Operating income (loss)									257.3	194.5	139.6
Depreciation									52.6	50.8	49.1
Other (income) expense, net									(14.5)	(5.7)
Segment assets	1,295.4				1,076.0				1,295.4	1,076.0	919.9
Accrual basis additions to property, plant and equipment									228.6	176.6	57.3
Engineered Products
Segment information
Third-Party Sales									347.3	317.9	269.1
Intersegment sales									2.0	1.6	0.6
Operating income (loss)									50.6	51.6	45.7
Depreciation									4.5	4.3	3.9
Equity in earnings from affiliated companies									0.7	1.6	0.5
Segment assets	215.2				192.3				215.2	192.3	176.8
Investments in affiliated companies	22.6				21.7				22.6	21.7	19.9
Accrual basis additions to property, plant and equipment									12.5	6.9	3.3
Corporate and Other
Segment information
Intersegment sales									(58.8)	(55.4)	(39.3)
Operating income (loss)									(59.1)	(54.1)	(55.5)
Depreciation									0.1	0.2	0.2
Other (income) expense, net									5.0	2.7	3.5
Segment assets	92.5				107.8				92.5	107.8	161.4
Accrual basis additions to property, plant and equipment									$ 0.2	$ 1.0	$ 0.1