Inventories (Schedule Of Inventory Costs) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventories [Abstract]
Raw materials	$ 305,603	$ 300,439
Work in process	7,524	7,321
Finished goods	2,436	2,215
Inventories	$ 315,563	$ 309,975

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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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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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