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Goodwill and Related Intangible Assets (Schedule of Changes in Carrying Amount of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Balance at	$ 307,355	$ 301,580
Acquired goodwill	205,243	5,857
Adjustments to prior year acquisitions	578	(172)
Foreign currency translation	1,103	90
Balance at	514,279	307,355
Renewable Energy & Conservation
Goodwill [Roll Forward]
Balance at	77,602	71,827
Acquired goodwill	197,866	5,857
Adjustments to prior year acquisitions	578	(172)
Foreign currency translation	1,103	90
Balance at	277,149	77,602
Residential Products
Goodwill [Roll Forward]
Balance at	198,075	198,075
Acquired goodwill	7,377	0
Adjustments to prior year acquisitions	0	0
Foreign currency translation	0	0
Balance at	205,452	198,075
Infrastructure Products
Goodwill [Roll Forward]
Balance at	31,678	31,678
Acquired goodwill	0	0
Adjustments to prior year acquisitions	0	0
Foreign currency translation	0	0
Balance at	$ 31,678	$ 31,678

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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-Publisher FASB
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-Topic 805
-SubTopic 10
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