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, 2013		Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Data - Income Statement [Abstract]
Revenues	$ 315,679	[1]	$ 307,665	[1]	$ 242,100	$ 225,976	$ 271,595	[2]	$ 262,867	[2]	$ 254,490	[2]	$ 227,879	$ 1,091,420	$ 1,016,831	$ 925,766
Gross profit	70,905	[1]	69,411	[1]	58,568	48,137	66,032	[2]	62,931	[2]	62,219	[2]	52,572	247,021	243,754	202,679
Operating income	22,209	[1]	22,032	[1]	15,823	6,818	25,097	[2]	26,865	[2]	18,654	[2]	11,187	66,882	81,803	45,707
Income from continuing operations	14,730	[1]	14,623	[1]	18,396	4,258	17,859	[2]	21,170	[2]	12,191	[2]	7,342
Loss from discontinued operations	(5)	[1]	(558)	[1]	(4,977)	(921)	(833)	[2]	(435)	[2]	(253)	[2]	(192)
Net income attributable to Aegion Corporation	$ 14,725	[1]	$ 14,065	[1]	$ 13,419	$ 3,337	$ 17,026	[2]	$ 20,735	[2]	$ 11,938	[2]	$ 7,150	$ 44,351	$ 52,661	$ 26,547
Basic earnings per share:
Income from continuing operations (in Dollars per share)	$ 0.38	[1]	$ 0.37	[1]	$ 0.47	$ 0.10	$ 0.40	[2]	$ 0.51	[2]	$ 0.30	[2]	$ 0.17	$ 1.31	$ 1.38	$ 0.68
Loss from discontinued operations (in Dollars per share)	$ 0.00	[1]	$ (0.01)	[1]	$ (0.13)	$ (0.03)	$ (0.02)	[2]	$ (0.01)	[2]	$ (0.01)	[2]	$ 0.00	$ (0.17)	$ (0.04)	$ (0.01)
Net income (in Dollars per share)	$ 0.38	[1]	$ 0.36	[1]	$ 0.34	$ 0.07	$ 0.38	[2]	$ 0.50	[2]	$ 0.29	[2]	$ 0.17	$ 1.14	$ 1.34	$ 0.67
Diluted earnings per share
Income from continuing operations (in Dollars per share)	$ 0.37	[1]	$ 0.37	[1]	$ 0.47	$ 0.09	$ 0.40	[2]	$ 0.50	[2]	$ 0.30	[2]	$ 0.17	$ 1.30	$ 1.37	$ 0.68
Loss from discontinued operations (in Dollars per share)	$ 0.00	[1]	$ (0.01)	[1]	$ (0.13)	$ (0.03)	$ (0.02)	[2]	$ (0.01)	[2]	$ (0.01)	[2]	$ 0.00	$ (0.17)	$ (0.04)	$ (0.01)
Net income (in Dollars per share)	$ 0.37	[1]	$ 0.36	[1]	$ 0.34	$ 0.06	$ 0.38	[2]	$ 0.49	[2]	$ 0.29	[2]	$ 0.17	$ 1.13	$ 1.33	$ 0.67

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

[2] (2) Includes the financial results of Fyfe Asia, which was acquired in April 2012.