Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) $ in Thousands	6 Months Ended
Jun. 30, 2020 USD ($)
Goodwill [Roll Forward]
Balance at December 31, 2019	$ 329,705
Acquired goodwill	49,001
Adjustments to prior year acquisitions	579
Foreign currency translation	(545)
Balance at June 30, 2020	378,740
Renewable Energy and Conservation
Goodwill [Roll Forward]
Balance at December 31, 2019	77,602
Acquired goodwill	49,001
Adjustments to prior year acquisitions	579
Foreign currency translation	(281)
Balance at June 30, 2020	126,901
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 June 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	(264)
Balance at June 30, 2020	$ 53,764

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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