Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 141	$ (74,044)	$ 5,863	$ (54,198)
Other comprehensive income (loss):
Currency translation adjustments		(6,701)	359	(10,983)	17,637
Deferred gain on hedging activity, net of tax	[1]	477	89	1,655	265
Pension activity, net of tax	[2]	2	(9)	7	(25)
Total comprehensive loss		(6,081)	(73,605)	(3,458)	(36,321)
Comprehensive (income) loss attributable to non-controlling interests		(660)	480	(283)	(2,500)
Comprehensive loss attributable to Aegion Corporation		$ (6,741)	$ (73,125)	$ (3,741)	$ (38,821)

[1] Amounts presented net of tax of $171 and $59 for the quarters ended September 30, 2018 and 2017, respectively, and $593 and $176 for the nine months ended September 30, 2018 and 2017, respectively.

[2] Amounts presented net of tax of $1 and $(2) for the quarters ended September 30, 2018 and 2017, respectively, and $2 and $(6) for the nine months ended September 30, 2018 and 2017, respectively.