Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues	$ 1,359,019	$ 1,221,920	$ 1,333,570
Cost of revenues	1,074,207	968,756	1,057,783
Gross profit	284,812	253,164	275,787
Operating expenses	225,826	197,099	209,477
Goodwill impairment	45,390	0	43,484
Definite-lived intangible asset impairment	41,032	0	0
Gain on litigation settlement	0	(6,625)	0
Acquisition and divestiture expenses	2,923	2,696	1,912
Restructuring and related charges	12,814	9,168	968
Operating income (loss)	(43,173)	50,826	19,946
Other income (expense):
Interest expense	(16,001)	(15,029)	(16,044)
Interest income	145	166	218
Other	(2,201)	(694)	(2,905)
Total other expense	(18,057)	(15,557)	(18,731)
Income (loss) before taxes on income	(61,230)	35,269	1,215
Taxes on income (loss)	5,005	6,109	9,205
Net income (loss)	(66,235)	29,160	(7,990)
Non-controlling interests (income) loss	(2,819)	328	(77)
Net income (loss) attributable to Aegion Corporation	$ (69,054)	$ 29,488	$ (8,067)
Basic:
Basic (in USD per share)	$ (2.08)	$ 0.85	$ (0.22)
Diluted:
Diluted (in USD per share)	$ (2.08)	$ 0.84	$ (0.22)