Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Balance at	$ 292,390	$ 236,044
Acquired goodwill	12,283	57,180
Impairment	(929)		$ (104,565)
Foreign currency translation	288	(834)
Balance at	304,032	292,390	236,044
Residential Products
Goodwill [Roll Forward]
Balance at	181,285	181,285
Acquired goodwill	0	0
Impairment	0
Foreign currency translation	0	0
Balance at	181,285	181,285	181,285
Industrial and Infrastructure Products
Goodwill [Roll Forward]
Balance at	53,704	54,759
Acquired goodwill	0	0
Impairment	0
Foreign currency translation	180	(1,055)
Balance at	53,884	53,704	54,759
Renewable Energy & Conservation
Goodwill [Roll Forward]
Balance at	57,401	0
Acquired goodwill	12,283	57,180
Impairment	(929)
Foreign currency translation	108	221
Balance at	$ 68,863	$ 57,401	$ 0