Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Goodwill [Roll Forward]
Balance at	$ 321,074
Foreign currency translation	698
Balance at	321,772
Residential Products
Goodwill [Roll Forward]
Balance at	198,075
Foreign currency translation	0
Balance at	198,075
Industrial and Infrastructure Products
Goodwill [Roll Forward]
Balance at	54,280
Foreign currency translation	(163)
Balance at	54,117
Renewable Energy & Conservation
Goodwill [Roll Forward]
Balance at	68,719
Foreign currency translation	861
Balance at	$ 69,580