Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) $ in Thousands	9 Months Ended
Sep. 30, 2020 USD ($)
Goodwill [Roll Forward]
Balance at December 31, 2019	$ 329,705
Acquired goodwill	51,629
Adjustments to prior year acquisitions	579
Foreign currency translation	514
Balance at September 30, 2020	382,427
Renewable Energy and Conservation
Goodwill [Roll Forward]
Balance at December 31, 2019	77,602
Acquired goodwill	51,629
Adjustments to prior year acquisitions	579
Foreign currency translation	664
Balance at September 30, 2020	130,474
Residential Products
Goodwill [Roll Forward]
Balance at December 31, 2019	198,075
Acquired goodwill	0
Adjustments to prior year acquisitions	0
Foreign currency translation	0
Balance at September 30, 2020	198,075
Industrial and Infrastructure Products
Goodwill [Roll Forward]
Balance at December 31, 2019	54,028
Acquired goodwill	0
Adjustments to prior year acquisitions	0
Foreign currency translation	(150)
Balance at September 30, 2020	$ 53,878

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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