Exit Activity Costs and Asset Impairments (Summary of Exit Activity Costs and Asset Impairments by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Total exit activity costs	$ 291	$ 219
Renewable Energy and Conservation
Restructuring Cost and Reserve [Line Items]
Total exit activity costs	18	94
Residential Products
Restructuring Cost and Reserve [Line Items]
Total exit activity costs	221	151
Industrial and Infrastructure Products
Restructuring Cost and Reserve [Line Items]
Total exit activity costs	(2)	(33)
Corporate
Restructuring Cost and Reserve [Line Items]
Total exit activity costs	$ 54	$ 7