For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The amount of LIFO (last in first out) inventory present at the reporting date when inventory is also valued using different valuation methods.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Amount of lessee's right to use underlying asset under operating lease.

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The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Number of Reportable Segments	3
LIFO Inventory Amount	$ 51.1	$ 48.1
Percentage of LIFO Inventory	13.90%	17.50%
Software and Software Development Costs [Member]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member]
Property, Plant and Equipment, Useful Life	2 years
Minimum [Member] \| Accounting Standards Update 2016-02 [Member] \| Subsequent Event [Member]
Operating Lease, Right-of-Use Asset				$ 22.0
Operating Lease, Liability, Total				22.0
Minimum [Member] \| Software and Software Development Costs [Member]
Property, Plant and Equipment, Useful Life	2 years
Maximum [Member]
Property, Plant and Equipment, Useful Life	30 years
Maximum [Member] \| Accounting Standards Update 2016-02 [Member] \| Subsequent Event [Member]
Operating Lease, Right-of-Use Asset				27.0
Operating Lease, Liability, Total				$ 27.0
Maximum [Member] \| Software and Software Development Costs [Member]
Property, Plant and Equipment, Useful Life	5 years
Steel Requirements [Member] \| Supplier Concentration Risk [Member] \| Three Largest Suppliers [Member]
Concentration Risk, Percentage	52.00%	53.00%	54.00%
Sales Revenue, Goods, Net [Member] \| Customer Concentration Risk [Member] \| Top 20 [Member]
Concentration Risk, Percentage	29.00%	27.00%	29.00%
Sales Revenue, Goods, Net [Member] \| Customer Concentration Risk [Member] \| Largest Customer [Member]
Concentration Risk, Percentage	5.00%	4.00%	4.00%
Sales Revenue, Goods, Net [Member] \| Customer Concentration Risk [Member] \| Industrial Machinery and Equipment Manufacturers and Fabricators [Member]
Concentration Risk, Percentage	48.00%	51.00%	51.00%