Note 13 - Selected Quarterly Data (Details) - Income Statement (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Data - Income Statement [Abstract]
Revenues	$ 352,181	[1]	$ 350,138	[2]	$ 322,868	$ 306,234	$ 315,679	[3]	$ 307,665	[3]	$ 242,100	$ 225,976	$ 1,331,421	[4]	$ 1,091,420	[4]	$ 1,016,831	[4]
Gross profit	83,063	[1]	63,939	[2]	71,918	61,063	70,905	[3]	69,411	[3]	58,568	48,137	279,983		247,021		243,754
Operating income	(35,631)	[1]	(13,934)	[2]	20,619	9,134	22,209	[3]	22,032	[3]	15,823	6,818	(19,812)		66,882		81,803
Income from continuing operations	(32,800)	[1]	(16,101)	[2]	12,776	4,560	14,730	[3]	14,623	[3]	18,396	4,258
Loss from discontinued operations	(3,221)	[1]	(130)	[2]	(364)	(132)	(5)	[3]	(558)	[3]	(4,977)	(921)
Net income attributable to Aegion Corporation	(36,021)	[1]	(16,231)	[2]	12,412	4,428	14,725	[3]	14,065	[3]	13,419	3,337	(37,167)		44,351		52,661
Basic earnings per share:
Income from continuing operations (in Dollars per share)	$ (0.90)	[1]	$ (0.45)	[2]	$ 0.34	$ 0.12	$ 0.38	[3]	$ 0.37	[3]	$ 0.47	$ 0.09	$ (0.88)		$ 1.31		$ 1.38
Loss from discontinued operations (in Dollars per share)	$ (0.09)	[1]	$ 0.00	[2]	$ (0.01)	$ 0.00	$ 0.00	[3]	$ (0.01)	[3]	$ (0.13)	$ (0.02)	$ (0.10)		$ (0.17)		$ (0.04)
Net income (in Dollars per share)	$ (0.99)	[1]	$ (0.45)	[2]	$ 0.33	$ 0.12	$ 0.38	[3]	$ 0.36	[3]	$ 0.34	$ 0.07	$ (0.98)		$ 1.14		$ 1.34
Diluted earnings per share
Income from continuing operations (in Dollars per share)	$ (0.90)	[1]	$ (0.45)	[2]	$ 0.33	$ 0.12	$ 0.37	[3]	$ 0.37	[3]	$ 0.47	$ 0.09	$ (0.88)		$ 1.30		$ 1.37
Loss from discontinued operations (in Dollars per share)	$ (0.09)	[1]	$ 0.00	[2]	$ (0.01)	$ 0.00	$ 0.00	[3]	$ (0.01)	[3]	$ (0.13)	$ (0.02)	$ (0.10)		$ (0.17)		$ (0.04)
Net income (in Dollars per share)	$ (0.99)	[1]	$ (0.45)	[2]	$ 0.32	$ 0.12	$ 0.37	[3]	$ 0.36	[3]	$ 0.34	$ 0.07	$ (0.98)		$ 1.13		$ 1.33
Restructuring charges	9,500		40,000										687		0		0
Asset Impairment Charges	$ 52,700												$ 11,870		$ 0		$ 0

[1] Includes expenses of $9.5 million related to our 2014 Restructuring Plan and $52.7 million related to certain goodwill and definite-lived intangible asset impairments (see Notes 2, 3 and 5).

[2] Includes expenses of $40.0 million related to our 2014 Restructuring Plan (see Note 3).

[3] Includes the financial results of Brinderson, which was acquired in July 2013 (see Note 1).

[4] Revenues and long-lived assets are attributed to the country of origin for the Company’s legal entities. For a significant majority of its legal entities, the country of origin relates to the country or geographic area that it services.