Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (66,235)	$ 29,160	$ (7,990)
Other comprehensive income (loss):
Currency translation adjustments		19,390	(6,343)	(25,379)
Deferred gain (loss) on hedging activity, net of tax	[1]	1,402	746	279
Pension activity, net of tax	[2]	93	(8)	145
Total comprehensive income (loss)		(45,350)	23,555	(32,945)
Comprehensive (income) loss attributable to non-controlling interests		(3,040)	294	1,686
Comprehensive income (loss) attributable to Aegion Corporation		$ (48,390)	$ 23,849	$ (31,259)

[1] Amounts presented net of tax of $22, $(2) and $37 for the years ended December 31, 2017, 2016, and 2015, respectively.

[2] Amounts presented net of tax of $930, $496 and $187 for the years ended December 31, 2017, 2016 and 2015, respectively.