Selected Balance Sheet Data (Schedule Of Inventories) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Inventory [Line Items]
Raw materials	$ 15,652	$ 14,764
Work-in process	2,430	2,467
Finished products and components	2,254	2,282
Total	20,336	19,513
Domestic [Member]
Inventory [Line Items]
Raw materials	12,256	11,371
Work-in process	1,191	1,499
Finished products and components	2,138	2,149
Total	15,585	15,019
Foreign [Member]
Inventory [Line Items]
Raw materials	3,396	3,393
Work-in process	1,239	968
Finished products and components	116	133
Total	$ 4,751	$ 4,494

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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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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Carrying amount, net of reserves and adjustments, as of the balance sheet date of merchandise or goods which are partially completed. This inventory is generally comprised of raw materials, labor and factory overhead costs, which require further materials, labor and overhead to be converted into finished goods, and which generally require the use of estimates to determine percentage complete and pricing.

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