Schedule III - Supplemental Financial Information (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Income Tax Expenses (Benefits) Related to US Tax Cuts and Jobs Act		$ 6,200
Tubular and Pipe Products [Member]
Inventory, LIFO Reserve, Effect on Income, Net, Total	$ 8,408	$ 2,707

The difference between the change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods and any LIFO decrement which have been reflected in the statement of income during the period.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration