Note 1 - Description of Business	12 Months Ended
Dec. 31, 2019
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	1. DESCRIPTION OF BUSINESS Aegion Corporation combines innovative technologies with market leading expertise to maintain, rehabilitate and strengthen pipelines and other infrastructure around the world. For nearly 50 years, the Company has played a pioneering role in finding transformational solutions to rehabilitate aging infrastructure, primarily pipelines in the wastewater, water, energy, mining and refining industries. The Company also maintains the efficient operation of refineries and other industrial facilities and provide innovative solutions for the strengthening of buildings, bridges and other structures. Aegion is committed to Stronger. Safer. Infrastructure^®. The Company believes that the depth and breadth of its products and services platform make Aegion a leading “one-stop” provider for the world’s infrastructure rehabilitation and protection needs. The Company is primarily built on the premise that it is possible to use technology to extend the structural design life and maintain, if not improve, the performance of infrastructure, mostly pipe. The Company is proving that this expertise can be applied in a variety of markets to protect pipelines in oil, gas, mining, wastewater and water applications and extending this to the rehabilitation and maintenance of commercial structures and the provision of professional services in energy-related industries. Many types of infrastructure must be protected from the corrosive and abrasive materials that pass through or near them. The Company’s expertise in non-disruptive corrosion engineering and abrasion protection is now wide-ranging, opening new markets for growth. The Company has a long history of product development and intellectual property management. The Company manufactures most of the engineered solutions it creates as well as the specialized equipment required to install them. Finally, decades of experience give the Company an advantage in understanding municipal, energy, mining, industrial and commercial customers. Strong customer relationships and brand recognition allow the Company to support the expansion of existing and innovative technologies into new high growth end markets. The Company’s predecessor was originally incorporated in Delaware in 1980 to act as the exclusive United States licensee of the Insituform^® cured-in-place pipe (“CIPP”) process, which Insituform’s founder invented in 1971. The Insituform^® CIPP process served as the first trenchless technology for rehabilitating sewer pipelines and has enabled municipalities and private industry to avoid the extraordinary expense and extreme disruption that can result from conventional “dig-and-replace” methods. For nearly 50 years, the Company has maintained its leadership position in the CIPP market from manufacturing to technological innovations and market share. In order to strengthen the Company’s ability to service the emerging demands of the infrastructure protection market and to better position the Company for sustainable growth, the Company embarked on a diversification strategy in 2009 to expand its product and service portfolio and its geographical reach. Through a series of strategic initiatives and key acquisitions, the Company now possesses a broad portfolio of cost-effective solutions for rehabilitating and maintaining aging or deteriorating infrastructure, protecting new infrastructure from corrosion worldwide and providing integrated professional services in engineering, procurement, construction, maintenance, and turnaround services for oil and natural gas companies, primarily in the midstream and downstream markets. Recognizing that the breadth of offerings expanded beyond the Company’s flagship Insituform^®brand, which constituted less than half of the Company’s revenues in 2011, the Company reorganized Insituform Technologies, Inc. (“Insituform”), the parent company at the time, into a new holding company structure in October 2011. Aegion became the new parent company and Insituform became a wholly-owned subsidiary of Aegion. Aegion reflects the Company’s mission of extending its leadership capabilities to furnish products and services to provide: (i) long-term protection for water and wastewater pipes, oil and gas pipelines and infrastructure as well as commercial and governmental structures and transportation infrastructure; and (ii) integrated professional services to energy companies. Strategic Initiatives/Acquisitions/Divestitures Restructuring Activities On July 28, 2017, the Company’s board of directors approved a comprehensive global realignment and restructuring plan (the “Restructuring”). As part of the Restructuring, the Company announced plans to: (i) divest the Company’s pipe coating and insulation businesses in Louisiana, The Bayou Companies, LLC and Bayou Wasco Insulation, LLC (collectively “Bayou”); (ii) exit all non-pipe related contract applications for the Tyfo^® system in North America; (iii) right-size the cathodic protection services operation in Canada and the CIPP businesses in Australia and Denmark; and (iv) reduce corporate and other operating costs. During 2018 and 2019, the Company’s board of directors approved additional actions with respect to the Restructuring, which included the decisions to: (i) divest the Australia and Denmark CIPP businesses; (ii) take actions to further optimize operations within North America, including measures to reduce consolidated operating costs; and (iii) divest or otherwise exit multiple additional international businesses, including: (a) the Company’s cathodic protection installation activities in the Middle East, including Corrpower International Limited, the Company’s cathodic protection materials manufacturing and production joint venture in Saudi Arabia; (b) United Pipeline de Mexico S.A. de C.V., the Company’s Tite Liner^® joint venture in Mexico (“United Mexico”); (c) the Company’s Tite Liner^® businesses in Brazil and Argentina; (d) Aegion South Africa Proprietary Limited, the Company’s Tite Liner^® and CIPP joint venture in the Republic of South Africa; and (e) the Company’s CIPP contract installation operations in England, the Netherlands, Spain and Northern Ireland. The Company completed the divestitures of Bayou and the Denmark CIPP business in 2018. The Company also completed the divestitures of the Netherlands CIPP business and its Tite Liner^® joint venture in Mexico in 2019, as well as the shutdown of activities for the CIPP business in England. The Company completed the divestitures of CIPP operations in Australia and Spain in early 2020 (see Note 17). Remaining divestiture and shutdown activities include the sale of the Northern Ireland contracting operation and minor final dissolution activities in South America and South Africa, all of which is expected to be completed in the first half of 2020. Additionally, the exit of the Company’s cathodic protection installation activities in the Middle East is substantially complete, though management expects minimal wind-down activities will extend through the second quarter of 2020 related to a small number of projects remaining in backlog. As part of efforts to optimize the cathodic protection operations in North America, the Company’s management initiated plans during the fourth quarter of 2019 to further downsize operations in the U.S., including the closure of three branch offices and the exit of capital intensive drilling activities at four branch offices. These actions included a reduction of approximately 20% of the cathodic protection domestic workforce and an exit of drilling activities that contributed approximately 20% to our cathodic protection domestic revenues in 2019. Management expects these actions to improve our cathodic protection cost structure in the U.S., eliminate unprofitable results in certain parts of the business and reduce consolidated annual expenses for the business overall. Also during the fourth quarter of 2019, the Company reduced corporate headcount and took other actions to reduce corporate costs. See Note 4. Infrastructure Solutions Segment (“Infrastructure Solutions”) During 2019, the Company initiated plans to sell its CIPP contracting business in Ireland, Environmental Techniques Limited (“Environmental Techniques”), and Spain, Insituform Technologies Iberica SA (“Insituform Spain”). Accordingly, the Company has classified the assets and liabilities as held for sale on the Consolidated Balance Sheet at December 31, 2019. See Note 6. Additionally, see Note 17 for additional information on the sale of Insituform Spain, effective February 13, 2020. In October 2019, the Company sold its CIPP contracting operations of Insituform Netherlands to GMB Rioleringstechnieken B.V., a Dutch company (“GMB”). In connection with the sale, the Company entered into a five-year tube supply agreement whereby GMB will buy liners from the Company. During 2018, the Company’s board of directors approved a plan to divest the Company’s CIPP business in Australia (“Insituform Australia”). While restructuring actions in Insituform Australia led to improvements in operating results, an assessment of the long-term fit within the Company’s portfolio led to the decision to divest the business. Accordingly, the Company has classified Insituform Australia’s assets and liabilities as held for sale on the Consolidated Balance Sheets at December 31, 2019 and 2018. See Note 6. Additionally, see Note 17 for additional information on the sale of Insituform Australia, effective January 24, 2020. In November 2018, the Company sold substantially all of the fixed assets and inventory from its CIPP operations in Denmark for a sale price of DKK 10.5 million (approximately $1.6 million). In connection with the sale, the Company entered into a five-year exclusive tube-supply agreement whereby the buyers will purchase Insituform^® CIPP liners from the Company. The buyers are also entitled to use the Insituform^® trade name based on a trademark license granted for the same five-year time period. In March 2017, the Company acquired Environmental Techniques Limited and its parent holding company, Killeen Trading Limited (collectively “Environmental Techniques”), for a purchase price of £6.5 million, approximately $8.0 million, which was funded from the Company’s international cash balances. Environmental Techniques provides trenchless drainage inspection, cleaning and rehabilitation services throughout the United Kingdom and the Republic of Ireland. Corrosion Protection Segment (“Corrosion Protection”) In October 2019, the Company sold its fifty-five percent (55%) interest in United Mexico, its Mexican Tite Liner^® joint venture, to its joint venture partner, Miller Pipeline de Mexico, S.A. de C.V., a Mexican company (“Miller”). Miller owned the remaining forty-five percent (45%) interest in United Mexico. In connection with the sale, the Company entered into a long-term license agreement pursuant to which United Mexico will be the exclusive licensee in Mexico with respect to certain trademarks, patents and other intellectual property relating to the Company’s pipe lining business. The Company further expects to enter into a long-term agreement for the supply of equipment and consumables as well as the provision of services to United Mexico. In August 2018, the Company sold substantially all of the assets of its wholly-owned subsidiary, The Bayou Companies, LLC and its fifty-one percent (51%) interest in Bayou Wasco Insulation, LLC. The sale price was $46 million, consisting of $38 million paid in cash at closing and $8 million in a fully secured, two-year loan payable to Aegion. Aegion is also eligible to receive an additional $4 million in total earn-out payments based on performance of the divested businesses in 2019 and 2020. Cash proceeds, net of customary closing costs, were used to repay outstanding borrowings on the Company’s line of credit. The sale resulted in a pre-tax loss of $7.0 million during 2018, which was included in “Other expense” in the Consolidated Statements of Operations. In May 2018, the Company acquired the operations of Hebna Inc., Hebna Canada Inc. and Hebna Corporation (collectively “Hebna”), for a purchase price of $6.0 million. The transaction was funded from a combination of domestic and international cash balances, with fifty percent (50%) of the purchase price being paid by the Company’s joint venture in Oman, in which the Company is a fifty-one percent (51%) partner. Hebna provides pipeline lining services, including compressed-fit lining, slip-lining, liner and free-standing pipe fusing, pipeline assessment and integrity management, pipeline pigging and calibration, and roto-lining services primarily in the United States, Canada and Middle East. Energy Services Segment (“Energy Services”) In July 2018, the Company acquired the operations of Plant Performance Services LLC and P2S LLC (collectively “P2S”), for a purchase price of $3.0 million. The transaction was funded from domestic cash balances. P2S specializes in general mechanical turnaround services, specialty welding services and field fabrication services primarily for the downstream oil and gas industry. Purchase Price Accounting The Company finalized its accounting for P2S and Hebna in 2019 and Environmental Techniques in 2018. There were no significant adjustments to the purchase price accounting in either period. In total, the transaction purchase price(s) to acquire P2S, Hebna and Environmental Techniques was approximately $17.0 million, of which, identified assets included goodwill of $7.3 million, intangible assets of $5.5 million, property, plant and equipment of $3.5 million and net working capital of $0.7 million. The goodwill and definite-lived intangible assets associated with the P2S and Hebna acquisitions are deductible for tax purposes; whereas, the goodwill and definite-lived intangible assets associated with the Environmental Techniques acquisition are not deductible for tax purposes. The Company’s acquisition of Environmental Techniques contributed revenues of $9.5 million, $7.5 million and $4.0 million, and net income (loss) of $(0.1) million, $0.1 million and $(0.7) million in 2019, 2018 and 2017, respectively. Revenue and net income contributions associated with Hebna and P2S were de minimus in 2019 and 2018.

Aegion Corporation combines innovative technologies with market leading expertise to maintain, rehabilitate and strengthen pipelines and other infrastructure around the world. For nearly 50 years, the Company has played a pioneering role in finding transformational solutions to rehabilitate aging infrastructure, primarily pipelines in the wastewater, water, energy, mining and refining industries. The Company also maintains the efficient operation of refineries and other industrial facilities and provide innovative solutions for the strengthening of buildings, bridges and other structures. Aegion is committed to Stronger. Safer. Infrastructure^®. The Company believes that the depth and breadth of its products and services platform make Aegion a leading “one-stop” provider for the world’s infrastructure rehabilitation and protection needs.

The Company is primarily built on the premise that it is possible to use technology to extend the structural design life and maintain, if not improve, the performance of infrastructure, mostly pipe. The Company is proving that this expertise can be applied in a variety of markets to protect pipelines in oil, gas, mining, wastewater and water applications and extending this to the rehabilitation and maintenance of commercial structures and the provision of professional services in energy-related industries. Many types of infrastructure must be protected from the corrosive and abrasive materials that pass through or near them. The Company’s expertise in non-disruptive corrosion engineering and abrasion protection is now wide-ranging, opening new markets for growth. The Company has a long history of product development and intellectual property management. The Company manufactures most of the engineered solutions it creates as well as the specialized equipment required to install them. Finally, decades of experience give the Company an advantage in understanding municipal, energy, mining, industrial and commercial customers. Strong customer relationships and brand recognition allow the Company to support the expansion of existing and innovative technologies into new high growth end markets.

The Company’s predecessor was originally incorporated in Delaware in 1980 to act as the exclusive United States licensee of the Insituform^® cured-in-place pipe (“CIPP”) process, which Insituform’s founder invented in 1971. The Insituform^® CIPP process served as the first trenchless technology for rehabilitating sewer pipelines and has enabled municipalities and private industry to avoid the extraordinary expense and extreme disruption that can result from conventional “dig-and-replace” methods. For nearly 50 years, the Company has maintained its leadership position in the CIPP market from manufacturing to technological innovations and market share.

In order to strengthen the Company’s ability to service the emerging demands of the infrastructure protection market and to better position the Company for sustainable growth, the Company embarked on a diversification strategy in 2009 to expand its product and service portfolio and its geographical reach. Through a series of strategic initiatives and key acquisitions, the Company now possesses a broad portfolio of cost-effective solutions for rehabilitating and maintaining aging or deteriorating infrastructure, protecting new infrastructure from corrosion worldwide and providing integrated professional services in engineering, procurement, construction, maintenance, and turnaround services for oil and natural gas companies, primarily in the midstream and downstream markets.

Recognizing that the breadth of offerings expanded beyond the Company’s flagship Insituform^®brand, which constituted less than half of the Company’s revenues in 2011, the Company reorganized Insituform Technologies, Inc. (“Insituform”), the parent company at the time, into a new holding company structure in October 2011. Aegion became the new parent company and Insituform became a wholly-owned subsidiary of Aegion. Aegion reflects the Company’s mission of extending its leadership capabilities to furnish products and services to provide: (i) long-term protection for water and wastewater pipes, oil and gas pipelines and infrastructure as well as commercial and governmental structures and transportation infrastructure; and (ii) integrated professional services to energy companies.

On July 28, 2017, the Company’s board of directors approved a comprehensive global realignment and restructuring plan (the “Restructuring”). As part of the Restructuring, the Company announced plans to: (i) divest the Company’s pipe coating and insulation businesses in Louisiana, The Bayou Companies, LLC and Bayou Wasco Insulation, LLC (collectively “Bayou”); (ii) exit all non-pipe related contract applications for the Tyfo^® system in North America; (iii) right-size the cathodic protection services operation in Canada and the CIPP businesses in Australia and Denmark; and (iv) reduce corporate and other operating costs.

During 2018 and 2019, the Company’s board of directors approved additional actions with respect to the Restructuring, which included the decisions to: (i) divest the Australia and Denmark CIPP businesses; (ii) take actions to further optimize operations within North America, including measures to reduce consolidated operating costs; and (iii) divest or otherwise exit multiple additional international businesses, including: (a) the Company’s cathodic protection installation activities in the Middle East, including Corrpower International Limited, the Company’s cathodic protection materials manufacturing and production joint venture in Saudi Arabia; (b) United Pipeline de Mexico S.A. de C.V., the Company’s Tite Liner^® joint venture in Mexico (“United Mexico”); (c) the Company’s Tite Liner^® businesses in Brazil and Argentina; (d) Aegion South Africa Proprietary Limited, the Company’s Tite Liner^® and CIPP joint venture in the Republic of South Africa; and (e) the Company’s CIPP contract installation operations in England, the Netherlands, Spain and Northern Ireland.

The Company completed the divestitures of Bayou and the Denmark CIPP business in 2018. The Company also completed the divestitures of the Netherlands CIPP business and its Tite Liner^® joint venture in Mexico in 2019, as well as the shutdown of activities for the CIPP business in England. The Company completed the divestitures of CIPP operations in Australia and Spain in early 2020 (see Note 17). Remaining divestiture and shutdown activities include the sale of the Northern Ireland contracting operation and minor final dissolution activities in South America and South Africa, all of which is expected to be completed in the first half of 2020. Additionally, the exit of the Company’s cathodic protection installation activities in the Middle East is substantially complete, though management expects minimal wind-down activities will extend through the second quarter of 2020 related to a small number of projects remaining in backlog.

As part of efforts to optimize the cathodic protection operations in North America, the Company’s management initiated plans during the fourth quarter of 2019 to further downsize operations in the U.S., including the closure of three branch offices and the exit of capital intensive drilling activities at four branch offices. These actions included a reduction of approximately 20% of the cathodic protection domestic workforce and an exit of drilling activities that contributed approximately 20% to our cathodic protection domestic revenues in 2019. Management expects these actions to improve our cathodic protection cost structure in the U.S., eliminate unprofitable results in certain parts of the business and reduce consolidated annual expenses for the business overall. Also during the fourth quarter of 2019, the Company reduced corporate headcount and took other actions to reduce corporate costs. See Note 4.

Infrastructure Solutions Segment (“Infrastructure Solutions”)

During 2019, the Company initiated plans to sell its CIPP contracting business in Ireland, Environmental Techniques Limited (“Environmental Techniques”), and Spain, Insituform Technologies Iberica SA (“Insituform Spain”). Accordingly, the Company has classified the assets and liabilities as held for sale on the Consolidated Balance Sheet at December 31, 2019. See Note 6. Additionally, see Note 17 for additional information on the sale of Insituform Spain, effective February 13, 2020.

In October 2019, the Company sold its CIPP contracting operations of Insituform Netherlands to GMB Rioleringstechnieken B.V., a Dutch company (“GMB”). In connection with the sale, the Company entered into a five-year tube supply agreement whereby GMB will buy liners from the Company.

During 2018, the Company’s board of directors approved a plan to divest the Company’s CIPP business in Australia (“Insituform Australia”). While restructuring actions in Insituform Australia led to improvements in operating results, an assessment of the long-term fit within the Company’s portfolio led to the decision to divest the business. Accordingly, the Company has classified Insituform Australia’s assets and liabilities as held for sale on the Consolidated Balance Sheets at December 31, 2019 and 2018. See Note 6. Additionally, see Note 17 for additional information on the sale of Insituform Australia, effective January 24, 2020.

In November 2018, the Company sold substantially all of the fixed assets and inventory from its CIPP operations in Denmark for a sale price of DKK 10.5 million (approximately $1.6 million). In connection with the sale, the Company entered into a five-year exclusive tube-supply agreement whereby the buyers will purchase Insituform^® CIPP liners from the Company. The buyers are also entitled to use the Insituform^® trade name based on a trademark license granted for the same five-year time period.

In March 2017, the Company acquired Environmental Techniques Limited and its parent holding company, Killeen Trading Limited (collectively “Environmental Techniques”), for a purchase price of £6.5 million, approximately $8.0 million, which was funded from the Company’s international cash balances. Environmental Techniques provides trenchless drainage inspection, cleaning and rehabilitation services throughout the United Kingdom and the Republic of Ireland.

Corrosion Protection Segment (“Corrosion Protection”)

In October 2019, the Company sold its fifty-five percent (55%) interest in United Mexico, its Mexican Tite Liner^® joint venture, to its joint venture partner, Miller Pipeline de Mexico, S.A. de C.V., a Mexican company (“Miller”). Miller owned the remaining forty-five percent (45%) interest in United Mexico. In connection with the sale, the Company entered into a long-term license agreement pursuant to which United Mexico will be the exclusive licensee in Mexico with respect to certain trademarks, patents and other intellectual property relating to the Company’s pipe lining business. The Company further expects to enter into a long-term agreement for the supply of equipment and consumables as well as the provision of services to United Mexico.

In August 2018, the Company sold substantially all of the assets of its wholly-owned subsidiary, The Bayou Companies, LLC and its fifty-one percent (51%) interest in Bayou Wasco Insulation, LLC. The sale price was $46 million, consisting of $38 million paid in cash at closing and $8 million in a fully secured, two-year loan payable to Aegion. Aegion is also eligible to receive an additional $4 million in total earn-out payments based on performance of the divested businesses in 2019 and 2020. Cash proceeds, net of customary closing costs, were used to repay outstanding borrowings on the Company’s line of credit. The sale resulted in a pre-tax loss of $7.0 million during 2018, which was included in “Other expense” in the Consolidated Statements of Operations.

In May 2018, the Company acquired the operations of Hebna Inc., Hebna Canada Inc. and Hebna Corporation (collectively “Hebna”), for a purchase price of $6.0 million. The transaction was funded from a combination of domestic and international cash balances, with fifty percent (50%) of the purchase price being paid by the Company’s joint venture in Oman, in which the Company is a fifty-one percent (51%) partner. Hebna provides pipeline lining services, including compressed-fit lining, slip-lining, liner and free-standing pipe fusing, pipeline assessment and integrity management, pipeline pigging and calibration, and roto-lining services primarily in the United States, Canada and Middle East.

Energy Services Segment (“Energy Services”)

In July 2018, the Company acquired the operations of Plant Performance Services LLC and P2S LLC (collectively “P2S”), for a purchase price of $3.0 million. The transaction was funded from domestic cash balances. P2S specializes in general mechanical turnaround services, specialty welding services and field fabrication services primarily for the downstream oil and gas industry.

Purchase Price Accounting

The Company finalized its accounting for P2S and Hebna in 2019 and Environmental Techniques in 2018. There were no significant adjustments to the purchase price accounting in either period. In total, the transaction purchase price(s) to acquire P2S, Hebna and Environmental Techniques was approximately $17.0 million, of which, identified assets included goodwill of $7.3 million, intangible assets of $5.5 million, property, plant and equipment of $3.5 million and net working capital of $0.7 million. The goodwill and definite-lived intangible assets associated with the P2S and Hebna acquisitions are deductible for tax purposes; whereas, the goodwill and definite-lived intangible assets associated with the Environmental Techniques acquisition are not deductible for tax purposes.

The Company’s acquisition of Environmental Techniques contributed revenues of $9.5 million, $7.5 million and $4.0 million, and net income (loss) of $(0.1) million, $0.1 million and $(0.7) million in 2019, 2018 and 2017, respectively. Revenue and net income contributions associated with Hebna and P2S were de minimus in 2019 and 2018.