Note 9 - Segment Reporting (Detail) - Financial Information by Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues	$ 265,155	$ 246,218	$ 753,281	$ 681,790
Gross profit	62,774	52,629	177,886	139,643
Operating income (loss)	26,142	9,498	55,404	22,827
Energy And Mining [Member]
Revenues	139,674	114,014	385,655	309,871
Gross profit	33,553	27,392	93,630	75,307
Operating income (loss)	20,703	7,118	41,600	20,493
North American Water and Wastewater [Member]
Revenues	77,818	95,200	231,647	266,606
Gross profit	17,183	15,882	48,850	40,292
Operating income (loss)	6,289	4,413	16,361	2,563
European Water and Wastewater [Member]
Revenues	18,748	22,176	52,343	66,545
Gross profit	4,450	5,899	12,158	16,533
Operating income (loss)	821	1,261	1,240	3,584
Asia-Pacific Water and Wastewater [Member]
Revenues	9,018	11,163	28,369	35,103
Gross profit	(1,560)	1,915	(2,555)	5,970
Operating income (loss)	(4,016)	(346)	(8,782)	(865)
Commercial And Structural [Member]
Revenues	19,897	3,665	55,267	3,665
Gross profit	9,148	1,541	25,803	1,541
Operating income (loss)	$ 2,345	$ (2,948)	$ 4,985	$ (2,948)