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Note 9 - Debt (Details Textual) $ in Thousands				12 Months Ended
Note 9 - Debt (Details Textual) $ in Thousands	Dec. 14, 2020 USD ($)	Jan. 10, 2019	Mar. 01, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2011 USD ($)
Prepaid Expense and Other Assets, Current				$ 5,069	$ 6,997
Interest Paid, Excluding Capitalized Interest, Operating Activities				7,002	10,951	$ 10,241
Long-term Debt, Gross				$ 188,400	$ 257,600	$ 275,300
Industrial Revenue Bond Member [Member]
Repayments of Long-term Debt, Total			$ 900
All Debt, Excluding Deferred Financing Fees and Deferred Commitment Fees [Member]
Debt Instrument, Interest Rate, Effective Percentage				3.25%	4.00%	3.70%
Chicago Tube and Iron Company Acquisition [Member] \| Industrial Revenue Bond Member [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt							$ 5,900
Interest Rate Swap [Member]
Debt Instrument, Term (Year)		5 years
Amortized Banking Fees [Member]
Prepaid Expense and Other Assets, Current				$ 900	$ 1,300
ABL Credit Facility [Member]
Derivative, Term of Contract (Year)				5 years
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 445,000
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, Current Borrowing Capacity	475,000
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				$ 47,500
Line of Credit Facility Covenant Terms Percentage of Aggregate Borrowing Base	10.00%
Line of Credit Facility Covenant Terms Aggregate Borrowing Base				$ 28,500
Line of Credit Facility Covenant Terms EBITDA Ratio				1.00
Line of Credit Facility, Remaining Borrowing Capacity				$ 120,700
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Base Rate [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate				0.00%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| Base Rate [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate				0.25%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate				1.25%
Asset Based Revolving Credit Facility Due December 8, 2022 [Member] \| ABL Credit Facility [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument, Basis Spread on Variable Rate				2.75%