Note 2 - Accounting Policies (Details) - Financial Data for Investments in Affiliated Companies (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Financial Data for Investments in Affiliated Companies [Abstract]
Current assets	$ 0	[1]	$ 10,220	[2]
Non-current assets	0	[1]	10,022	[2]
Current liabilities	0	[1]	1,743	[2]
Non-current liabilities	0	[1]	0	[2]
income statement data
Revenue	9,088	[1]	89,157	[2]	141,233	[2]
Gross profit	3,489	[1]	27,336	[2]	40,342	[2]
Net income	2,413	[1]	17,946	[2]	22,009	[2]
Equity in earnings of affiliated companies	$ 570	[1]	$ 5,159	[2]	$ 6,359	[2]

[1] Bayou Coating was sold in March 2014. Income statement data in 2014 includes only those results up to the date of its sale.

[2] Includes the financial data of Insituform-Germany through the date of its sale in June 2013.