Industry Segments and Geographic Area Information - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) group	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Concentration Risk [Line Items]
Export sales from United States | $	$ 261.9	$ 217.2	$ 213.8
Net Sales Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	11.00%	10.00%
Long-lived assets Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	8.00%	11.00%	10.00%
Canada | Net Sales Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	27.00%
Canada | Long-lived assets Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	13.00%
United Kingdom | Net Sales Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	33.00%
United Kingdom | Long-lived assets Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	33.00%
Mexico | Long-lived assets Total | Geographic Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	18.00%
Electrical
Concentration Risk [Line Items]
Number of business groups | group	3