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Note 16 - Segment Information (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Customer One [Member]
Concentration Risk, Percentage				16.00%	15.00%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Customer Two [Member]
Concentration Risk, Percentage				10.00%
Water Transmission Group [Member]
Goodwill, Impairment Loss	$ 5,300,000		$ 5,300,000
Tubular Products [Member]
Goodwill, Impairment Loss		$ 16,100,000		$ 16,100,000	$ 0
MEXICO
Property, Plant and Equipment, Net		4,200,000	4,300,000	4,200,000
Goodwill, Impairment Loss			5,282,000	16,066,000
Property, Plant and Equipment, Net		$ 132,595,000	$ 131,848,000	$ 132,595,000

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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+ References

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