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Acquisitions (Narrative) (Details) $ in Thousands					3 Months Ended	6 Months Ended
	Dec. 11, 2020 USD ($)	Oct. 15, 2020 USD ($)	Feb. 13, 2020 USD ($)	Jan. 15, 2020 USD ($)	Mar. 31, 2021 business	Jun. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Number of businesses acquired | business					5
Goodwill							$ 508,660	$ 514,279
Renewables
Business Acquisition [Line Items]
Number of businesses acquired | business					2
Goodwill							187,214	192,527
Agtech
Business Acquisition [Line Items]
Number of businesses acquired | business					2
Goodwill							84,316	84,622
Residential
Business Acquisition [Line Items]
Number of businesses acquired | business					1
Goodwill							$ 205,452	205,452
TerraSmart LLC
Business Acquisition [Line Items]
Acquisition purchase price						$ 223,900
Goodwill								$ 139,106
Sunfig Corporation
Business Acquisition [Line Items]
Acquisition purchase price	$ 3,800
Goodwill	$ 3,500
Architectural Mailboxes, LLC
Business Acquisition [Line Items]
Acquisition purchase price		$ 26,900
Goodwill		$ 7,400
Delta Separations, LLC
Business Acquisition [Line Items]
Acquisition purchase price			$ 47,100
Goodwill			$ 32,200
Thermo Energy Systems
Business Acquisition [Line Items]
Acquisition purchase price				$ 7,300
Goodwill				$ 18,700

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