Restructuring Costs and Other - By Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.4	$ 3.3	$ 3.1	$ 13.5
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.0	2.2	2.2	9.6
Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.4	1.1	0.9	3.9
Electrical Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.4	2.8	2.1	11.5
Electrical Segment | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.9	1.9	2.0	8.2
Electrical Segment | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.5	0.9	0.1	3.3
Power Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1.0	0.5	1.0	2.0
Power Segment | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.1	0.3	0.2	1.4
Power Segment | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.9	$ 0.2	$ 0.8	$ 0.6