Segments (Schedule of Segment Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales:
Net sales	$ 405.9	$ 414.3	$ 432.2	$ 405.7	$ 366.0	$ 352.2	$ 350.9	$ 343.8	$ 1,658.1	$ 1,412.9	$ 1,276.9
Segment operating income:
Total segment operating income									97.3	83.8	63.0
Gain on sale of assets			$ 1.9						1.9	0.0	0.0
Litigation settlement gain								$ 3.3	0.0	3.3	0.0
Asset impairment charge									0.0	0.0	(4.0)
Other components of pension income and other postretirement benefits expense, net									8.8	6.4	6.2
Interest expense, net									(34.3)	(31.5)	(28.2)
Loss on extinguishment of debt							$ (11.0)		0.0	(11.0)	0.0
Income before income taxes									71.8	47.7	41.0
Capital expenditures:									45.1	27.9	28.5
Depreciation and amortization expense:									36.3	31.5	29.5
Identifiable assets:	1,208.5				1,132.5				1,208.5	1,132.5	974.3
Operating Segments
Net sales:
Net sales									1,658.1	1,412.9	1,276.9
Segment operating income:
Total segment operating income									130.3	110.6	94.9
Segment Reconciling Items
Segment operating income:
Total segment operating income									97.3	83.8	63.0
Corporate costs									(34.9)	(30.1)	(27.9)
Gain on sale of assets									1.9	0.0	0.0
Litigation settlement gain									0.0	3.3	0.0
Other components of pension income and other postretirement benefits expense, net									8.8	6.4	6.2
Interest expense, net									(34.3)	(31.5)	(28.2)
Loss on extinguishment of debt									0.0	(11.0)	0.0
Corporate
Segment operating income:
Capital expenditures:									0.2	0.3	0.0
Depreciation and amortization expense:									0.4	0.5	0.6
Identifiable assets:	67.0				83.1				67.0	83.1	74.5
Supply Technologies
Net sales:
Net sales									636.8	561.8
Segment operating income:
Capital expenditures:									5.2	3.3	6.1
Depreciation and amortization expense:									5.3	4.7	4.7
Identifiable assets:	330.1				344.4				330.1	344.4	262.0
Supply Technologies | Operating Segments
Net sales:
Net sales									636.8	561.8	502.1
Segment operating income:
Total segment operating income									49.0	43.3	37.5
Assembly Components
Net sales:
Net sales									578.3	524.5
Segment operating income:
Capital expenditures:									24.3	18.6	16.9
Depreciation and amortization expense:									22.2	20.7	20.1
Identifiable assets:	378.3				351.4				378.3	351.4	332.9
Assembly Components | Operating Segments
Net sales:
Net sales									578.3	524.5	529.4
Segment operating income:
Total segment operating income									42.9	47.8	48.0
Engineered Products
Net sales:
Net sales									443.0	326.6
Segment operating income:
Capital expenditures:									15.4	5.7	5.5
Depreciation and amortization expense:									8.4	5.6	4.1
Identifiable assets:	$ 433.1				$ 353.6				433.1	353.6	304.9
Engineered Products | Operating Segments
Net sales:
Net sales									443.0	326.6	245.4
Segment operating income:
Total segment operating income									$ 38.4	$ 19.5	$ 9.4