Segments (Schedule of Segment Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net sales:
Net sales	$ 360.4	$ 340.2	$ 228.3	$ 366.3	$ 379.5	$ 403.4	$ 415.3	$ 420.1	$ 1,295.2	$ 1,618.3	$ 1,658.1
Segment operating income:
Total segment operating income									15.7	83.1	97.3
Gain on sale of assets									0.0	0.0	1.9
Other components of pension income and other postretirement benefits expense, net									7.3	5.6	8.8
Interest expense, net									(30.3)	(33.8)	(34.3)
(Loss) income before income taxes									(7.3)	54.9	71.8
Capital expenditures									26.3	40.1	45.1
Depreciation and amortization expense									35.8	34.2	36.3
Identifiable assets	1,300.5				1,310.4				1,300.5	1,310.4	1,208.5
Supply Technologies
Net sales:
Net sales									510.1	611.5	636.8
Assembly Components
Net sales:
Net sales									441.5	539.5	578.3
Engineered Products
Net sales:
Net sales									343.6	467.3	443.0
Operating Segments
Segment operating income:
Total segment operating income									41.8	115.9	130.3
Capital expenditures									26.3	40.1	45.1
Depreciation and amortization expense									35.8	34.2	36.3
Operating Segments | Supply Technologies
Segment operating income:
Total segment operating income									30.2	42.0	49.0
Capital expenditures									6.5	6.1	5.2
Depreciation and amortization expense									5.1	4.8	5.3
Identifiable assets	347.6				355.9				347.6	355.9	330.1
Operating Segments | Assembly Components
Segment operating income:
Total segment operating income									8.1	36.2	42.9
Capital expenditures									13.1	19.5	24.3
Depreciation and amortization expense									20.7	20.1	22.2
Identifiable assets	401.1				413.4				401.1	413.4	378.3
Operating Segments | Engineered Products
Segment operating income:
Total segment operating income									3.5	37.7	38.4
Capital expenditures									6.5	14.3	15.4
Depreciation and amortization expense									9.6	8.8	8.4
Identifiable assets	439.7				455.1				439.7	455.1	433.1
Corporate
Segment operating income:
Corporate costs									(26.1)	(28.5)	(34.9)
Capital expenditures									0.2	0.2	0.2
Depreciation and amortization expense									0.4	0.5	0.4
Identifiable assets	$ 112.1				$ 86.0				112.1	86.0	67.0
Segment Reconciling Items
Segment operating income:
One-time net expense related to former President									0.0	(4.3)	0.0
Gain on sale of assets									$ 0.0	$ 0.0	$ 1.9