Accounting Policies - VIE Income Statement (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Accounting Policies [Abstract]
Revenue	$ 72,916	$ 35,409
Gross profit	11,704	2,713
Net income (loss) attributable to Aegion Corporation	$ 3,071	$ (3,869)