Exit Activity Costs and Asset Impairments (Summary of Exit Activity Costs and Asset Impairments by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment recoveries, net	$ (1,820)	$ 164	$ (2,737)	$ 1,074
Exit activity costs	2,026	945	5,945	1,733
Net asset impairment and exit activity charges (gains)	206	1,109	3,208	2,807
Residential Products
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment recoveries, net	(126)	118	(147)	806
Exit activity costs	207	140	392	470
Net asset impairment and exit activity charges (gains)	81	258	245	1,276
Industrial and Infrastructure Products
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment recoveries, net	(1,694)	46	(2,590)	268
Exit activity costs	315	805	2,971	1,263
Net asset impairment and exit activity charges (gains)	(1,379)	851	381	1,531
Renewable Energy & Conservation
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment recoveries, net	0	0	0	0
Exit activity costs	1,369	0	2,419	0
Net asset impairment and exit activity charges (gains)	1,369	0	2,419	0
Corporate
Restructuring Cost and Reserve [Line Items]
Inventory write-downs &/or asset impairment recoveries, net	0	0	0	0
Exit activity costs	135	0	163	0
Net asset impairment and exit activity charges (gains)	$ 135	$ 0	$ 163	$ 0