Revenue (Summary of Disaggregation of Revenue by Product Line) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 432.2	$ 350.9	$ 837.9	$ 694.7
Supply Technologies Segment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	166.2	142.4	327.1	275.6
Supply Technologies Segment | Supply Technologies
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	146.1	121.7	284.9	233.7
Supply Technologies Segment | Engineered specialty fasteners and other products
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	20.1	20.7	42.2	41.9
Assembly Components Segment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	153.2	126.0	298.6	265.3
Assembly Components Segment | Fuel, rubber and plastic products
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	99.2	96.8	198.4	192.6
Assembly Components Segment | Aluminum products
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	54.0	29.2	100.2	72.7
Engineered Products Segment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	112.8	82.5	212.2	153.8
Engineered Products Segment | Industrial equipment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	78.5	70.3	153.0	128.9
Engineered Products Segment | Forged and machined products
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenues	$ 34.3	$ 12.2	$ 59.2	$ 24.9