Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 1,333,568	$ 1,359,019	$ 1,221,920
Cost of revenues	1,066,642	1,074,207	967,993
Gross profit	266,926	284,812	253,927
Operating expenses	219,823	226,173	197,897
Goodwill impairment	1,389	45,390	0
Definite-lived intangible asset impairment	2,169	41,032	0
Gain on litigation settlement	0	0	(6,625)
Acquisition and divestiture expenses	7,004	2,923	2,696
Restructuring and related charges	6,894	12,814	9,168
Operating income (loss)	29,647	(43,520)	50,791
Other income (expense):
Interest expense	(17,327)	(16,001)	(15,029)
Interest income	516	145	166
Other	(9,881)	(2,201)	(694)
Total other expense	(26,692)	(18,057)	(15,557)
Income (loss) before taxes on income	2,955	(61,577)	35,234
Taxes (benefit) on income (loss)	(132)	5,005	6,109
Net income (loss)	3,087	(66,582)	29,125
Non-controlling interests (income) loss	(159)	(2,819)	328
Net income (loss) attributable to Aegion Corporation	$ 2,928	$ (69,401)	$ 29,453
Earnings (loss) per share attributable to Aegion Corporation:
Basic (in USD per share)	$ 0.09	$ (2.09)	$ 0.85
Diluted (in USD per share)	$ 0.09	$ (2.09)	$ 0.84