General - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenues	$ 326,057	$ 302,869
Net income (loss) attributable to Aegion Corporation	$ 5,698	$ (3,330)
Diluted earnings (loss) per share (in dollars per share)	$ 0.17	$ (0.09)

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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