Accounting Policies - VIE Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Revenue	$ 16,051	$ 34,061
Gross profit	3,310	5,530
Net income attributable to Aegion Corporation	$ 1,248	$ 1,272