Segments (Schedule of Segment Information) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017
Net sales:
Total revenues	$ 414.3	$ 352.2		$ 1,252.2	$ 1,046.9
Segment operating income:
Total segment operating income	24.8	19.0		74.1	62.3
Gain on sale of assets	0.0	0.0		1.9	0.0
Litigation settlement gain	0.0	0.0	$ 3.3	0.0	3.3
Other components of pension income and other postretirement benefits expense, net	2.0	1.7		6.4	4.7
Interest expense, net	(8.9)	(7.8)		(26.1)	(23.1)
Loss on extinguishment of debt	0.0	0.0		0.0	(11.0)
Income before income taxes	17.9	12.9		54.4	32.9
Supply Technologies
Net sales:
Total revenues	155.1	140.2		482.2	415.8
Assembly Components
Net sales:
Total revenues	146.1	127.9		444.7	393.2
Engineered Products
Net sales:
Total revenues	113.1	84.1		325.3	237.9
Operating Segments
Net sales:
Total revenues	414.3	352.2		1,252.2	1,046.9
Segment operating income:
Total segment operating income	32.8	26.5		98.3	80.4
Operating Segments | Supply Technologies
Net sales:
Total revenues	155.1	140.2		482.2	415.8
Segment operating income:
Total segment operating income	11.3	10.2		37.3	32.8
Operating Segments | Assembly Components
Net sales:
Total revenues	146.1	127.9		444.7	393.2
Segment operating income:
Total segment operating income	9.3	10.7		33.6	35.2
Operating Segments | Engineered Products
Net sales:
Total revenues	113.1	84.1		325.3	237.9
Segment operating income:
Total segment operating income	12.2	5.6		27.4	12.4
Segment Reconciling Items
Segment operating income:
Total segment operating income	24.8	19.0		74.1	62.3
Corporate costs	(8.0)	(7.5)		(26.1)	(21.4)
Gain on sale of assets	0.0	0.0		1.9	0.0
Litigation settlement gain	0.0	0.0		0.0	3.3
Other components of pension income and other postretirement benefits expense, net	2.0	1.7		6.4	4.7
Interest expense, net	(8.9)	(7.8)		(26.1)	(23.1)
Loss on extinguishment of debt	$ 0.0	$ 0.0		$ 0.0	$ (11.0)