Restructuring Costs and Other - By Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.7	$ 5.5
Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.8	4.2
Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(0.1)	1.3
Electrical Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.7	4.7
Electrical Segment | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.8	3.7
Electrical Segment | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(0.1)	1.0
Power Segment
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0	0.8
Power Segment | Cost of goods sold
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0	0.5
Power Segment | Selling & administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.0	$ 0.3