Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Goodwill [Roll Forward]
Balance at	$ 323,671
Adjustments to prior year acquisitions	(172)
Foreign currency translation	74
Balance at	323,573
Residential Products
Goodwill [Roll Forward]
Balance at	198,075
Adjustments to prior year acquisitions	0
Foreign currency translation	0
Balance at	198,075
Industrial and Infrastructure Products
Goodwill [Roll Forward]
Balance at	53,769
Adjustments to prior year acquisitions	0
Foreign currency translation	116
Balance at	53,885
Renewable Energy & Conservation
Goodwill [Roll Forward]
Balance at	71,827
Adjustments to prior year acquisitions	(172)
Foreign currency translation	(42)
Balance at	$ 71,613