Inventories (Schedule of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory [Line Items]
Raw material	$ 66,018	$ 42,030
Work-in-process	5,382	5,023
Finished goods	31,205	18,460
Gross inventory	102,605	65,513
Less reserves	(4,298)	(3,556)
Total inventories	98,307	$ 61,957
Thermo Energy Systems Inc., Delta Separations, LLC, Architectural Mailboxes LLC , Sunfig Corporation, and TerraSmart LLC
Inventory [Line Items]
Total inventories	$ 30,000

Amount of inventory reserves for last-in first-out (LIFO) and other inventory valuation methods.

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Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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