Note 9 - Segment Reporting (Detail) - Financial Information by Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues	$ 231,652	$ 230,594
Gross profit	47,059	52,684
Operating income (loss)	5,281	10,899
Energy And Mining [Member]
Revenues	114,366	115,038
Gross profit	23,188	26,899
Operating income (loss)	3,914	7,440
North American Water and Wastewater [Member]
Revenues	77,641	74,338
Gross profit	14,450	14,571
Operating income (loss)	3,725	4,190
International Water and Wastewater [Member]
Revenues	26,155	26,671
Gross profit	4,711	3,606
Operating income (loss)	(1,163)	(2,078)
Commercial And Structural [Member]
Revenues	13,490	14,547
Gross profit	4,710	7,608
Operating income (loss)	$ (1,195)	$ 1,347