Accounting Policies - VIE Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounting Policies [Abstract]
Revenue	$ 5,925	$ 16,051
Gross profit	1,635	3,310
Net income attributable to Aegion Corporation	$ 33	$ 1,248