Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 339,679	$ 341,872	$ 999,570	$ 1,021,520
Cost of revenues	267,006	268,430	794,340	800,898
Gross profit	72,673	73,442	205,230	220,622
Operating expenses	51,386	54,872	161,750	165,812
Goodwill impairment	1,389	45,390	1,389	45,390
Definite-lived intangible asset impairment	870	41,032	870	41,032
Acquisition and divestiture expenses	4,800	1,980	6,024	2,513
Restructuring and related charges	1,219	5,439	4,548	5,439
Operating income (loss)	13,009	(75,271)	30,649	(39,564)
Other income (expense):
Interest expense	(3,870)	(3,962)	(13,236)	(12,014)
Interest income	130	33	239	117
Other	(9,281)	(798)	(10,049)	(1,593)
Total other expense	(13,021)	(4,727)	(23,046)	(13,490)
Income (loss) before taxes on income	(12)	(79,998)	7,603	(53,054)
Taxes (benefit) on income (loss)	(153)	(5,954)	1,740	1,144
Net income (loss)	141	(74,044)	5,863	(54,198)
Non-controlling interests (income) loss	(588)	546	(458)	(2,414)
Net income (loss) attributable to Aegion Corporation	$ (447)	$ (73,498)	$ 5,405	$ (56,612)
Earnings (loss) per share attributable to Aegion Corporation:
Net income (loss) per share, basic (in dollars per share)	$ (0.01)	$ (2.23)	$ 0.17	$ (1.70)
Net income (loss) per share, diluted (in dollars per share)	$ (0.01)	$ (2.23)	$ 0.16	$ (1.70)