Note 2 - Summary of Accounting Policies (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2012
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax (in Dollars)	$ 16,300,000		$ 6,900,000
Research and Development Expense (in Dollars)	1,800,000		2,200,000	2,700,000
Provision for Loss on Contracts (in Dollars)	600,000		900,000	800,000
Long-Term Growth Rate Assumption, Minimum					3.00%
Five-Year Compound Annual Growth Rate Assumption, Maximum					15.00%
Five-Year Compound Annual Growth Rate Assumption, Minimum					1.00%
Long-Term Growth Rate Assumption, Maximum					3.50%
Discount Rate Assumption, Minimum					13.00%
Discount Rate Assumption, Maximum					17.50%
Fair Value, Percent of Carrying Value	35.00%
Goodwill (in Dollars)	273,661,000	[1]	249,888,000
Reporting Unit Information, Increase (Decrease) Fair Value of Reporting Unit (in Dollars)	(17,200,000)
Reporting Unit Information Increase (Decrease) Fair Value of Reporting Unit, Percent	17.40%
Equity Method Investment, Minimum Threshold	20.00%
Equity Method Investment, Maximum Threshold	50.00%
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures (in Dollars)	19,181,000		19,314,000
Minimum [Member] | Goodwill [Member]
Number of Reportable Segments	5
Maximum [Member] | Goodwill [Member]
Number of Reportable Segments	5
Goodwill [Member]
Number of Reportable Segments	10
Benchmark 1 [Member]
Fair Value as Percentage of Carrying Value Benchmark					15.00%
Reporting Units with Fair Value within 15% of Carrying Value [Member]
Goodwill (in Dollars)					139,000,000
European Sewer and Water Rehabilitation [Member]
Fair Value as Percentage of Carrying Value Benchmark	2.60%
Goodwill (in Dollars)	$ 22,300,000	[1]	$ 21,800,000
WCU [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.00%
Bayou Coating [Member]
Equity Method Investment, Ownership Percentage	49.00%
Bayou Delta [Member]
Equity Method Investment, Ownership Percentage	41.00%
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares)	223,536		189,202	265,268
Retainage [Member]
Retainage Balance Greater Than 365 Days, Percent	9.00%
Minimum [Member]
Municipalities Collection Term	60 years
Percent of Contract Value Withheld Pending Project Completion	5.00%
Other Customers Collections Term	30 years
Maximum [Member]
Municipalities Collection Term	90 years
Percent of Contract Value Withheld Pending Project Completion	15.00%
Other Customers Collections Term	45 years

[1] The Company does not have any accumulated impairment charges.