Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Balance at	$ 304,032
Acquired goodwill	16,931
Adjustments to prior year acquisitions	(832)
Foreign currency translation	717
Balance at	320,848
Accumulated impairment losses	235,419	$ 234,490
Residential Products
Goodwill [Roll Forward]
Balance at	181,285
Acquired goodwill	16,931
Adjustments to prior year acquisitions	0
Foreign currency translation	0
Balance at	198,216
Industrial and Infrastructure Products
Goodwill [Roll Forward]
Balance at	53,884
Acquired goodwill	0
Adjustments to prior year acquisitions	0
Foreign currency translation	197
Balance at	54,081
Renewable Energy & Conservation
Goodwill [Roll Forward]
Balance at	68,863
Acquired goodwill	0
Adjustments to prior year acquisitions	(832)
Foreign currency translation	520
Balance at	$ 68,551