Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of cash paid for interest. Includes, but is not limited to, payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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The minimum commitments or obligations by the company that would require the Company to maintain certain EBITDA ratios under the revolver commitments.

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Effectof swap interest rate agreement.

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Note 6 - Debt (Details Textual) $ in Thousands			12 Months Ended
Note 6 - Debt (Details Textual) $ in Thousands	Dec. 08, 2017 USD ($)	Apr. 03, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 31, 2011 USD ($)
Prepaid Expense and Other Assets, Current			$ 8,333	$ 6,197
Debt Instrument, Interest Rate, Effective Percentage			3.00%	2.40%	2.10%
Interest Paid			$ 6,400	$ 4,300	$ 5,100
Long-term Debt, Gross			$ 200,600	$ 152,500	$ 211,200
Industrial Revenue Bonds [Member]
Repayments of Long-term Debt		$ 900
Debt Instrument, Interest Rate, Effective Percentage			1.71%
Effect of Swap Interest Rate Agreement			3.46%
Industrial Revenue Bonds [Member] \| Chicago Tube and Iron Company Acquisition [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt						$ 5,900
Amortized Banking Fees [Member]
Prepaid Expense and Other Assets, Current			$ 1,900
ABL Credit Facility [Member]
Debt Instrument, Term			5 years
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 370,000
Letters of Credit, Maximum Borrowing Capacity	20,000
Maximum First In, Last Out Revolving Credit Facility	30,000
Line of Credit Facility, Additional Commitments, Maximum	200,000
Line Of Credit Facility Covenant Terms Monetary	$ 30,000
Line of Credit Facility Covenant Terms Percentage of Revolver Commitments	10.00%
Balance Required for Compliance with Revolver Commitments			$ 40,000
Line of Credit Facility Covenant Terms Percentage of Aggregate Borrowing Base	10.00%
Line of Credit Facility Covenant Terms Aggregate Borrowing Base			32,900
Line of Credit Facility Covenant Terms EBITDA Ratio	1
Line of Credit Facility, Remaining Borrowing Capacity			$ 128,900
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Minimum [Member] \| Base Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Minimum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Maximum [Member] \| Base Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Maximum [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate	2.75%