Note 4 - Costs and Estimated Earnings in Excess of Billings on Uncompleted Contracts and Billings in Excess of Costs and Estimated Earnings - Uncompleted Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Costs incurred on uncompleted contracts	$ 227,048	$ 238,050
Estimated earnings	9,722	7,247
Sum of costs incurred and estimated earnings on uncompleted contracts	236,770	245,297
Less billings to date	(194,867)	(203,672)
Costs and estimated earnings in excess of billings on uncompleted contracts, net	41,903	41,625
Costs and estimated earnings in excess of billings on uncompleted contracts	44,502	43,663
Billings in excess of costs and estimated earnings on uncompleted contracts	(2,599)	(2,038)
Costs and estimated earnings in excess of billings on uncompleted contracts, net	$ 41,903	$ 41,625

Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method that are expected to be realized within one year or one operating cycle, whichever is longer, from the reporting date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57788-111642

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57807-111642

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 35
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68068069&loc=d3e57795-111642

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