Exit Activity Costs and Asset Impairments (Summary of Exit Activity Costs and Asset Impairments by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment (recoveries) charges, net	$ 479	$ 1,750	$ 479	$ 1,088
Exit activity costs	3,504	1,910	5,859	2,264
Total exit activity costs & asset impairments	3,983	3,660	6,338	3,352
Renewable Energy and Conservation
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment (recoveries) charges, net	(9)	0	(9)	84
Exit activity costs	46	(156)	45	(107)
Total exit activity costs & asset impairments	37	(156)	36	(23)
Residential Products
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment (recoveries) charges, net	478	1,392	478	1,349
Exit activity costs	2,937	485	3,307	333
Total exit activity costs & asset impairments	3,415	1,877	3,785	1,682
Industrial and Infrastructure Products
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment (recoveries) charges, net	10	358	10	(345)
Exit activity costs	275	1,417	1,588	1,607
Total exit activity costs & asset impairments	285	1,775	1,598	1,262
Corporate
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment (recoveries) charges, net	0	0	0	0
Exit activity costs	246	164	919	431
Total exit activity costs & asset impairments	$ 246	$ 164	$ 919	$ 431