Aegion 10-Q 3 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 26, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Aegion Corp
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		32,399,764
Amendment Flag	false
Entity Central Index Key	353,020
Entity Filer Category	Large Accelerated Filer
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Revenues	$ 324,861	$ 325,175
Cost of revenues	263,357	257,763
Gross profit	61,504	67,412
Operating expenses	56,142	52,746
Acquisition and divestiture expenses	392	533
Restructuring and related charges	1,789	0
Operating income	3,181	14,133
Other income (expense):
Interest expense	(5,443)	(4,047)
Interest income	47	49
Other	(262)	(387)
Total other expense	(5,658)	(4,385)
Income (loss) before taxes on income	(2,477)	9,748
Taxes (benefit) on income (loss)	(1,001)	1,995
Net income (loss)	(1,476)	7,753
Non-controlling interests income	(593)	(1,882)
Net income (loss) attributable to Aegion Corporation	$ (2,069)	$ 5,871
Earnings (loss) per share attributable to Aegion Corporation:
Net income (loss) per share, basic (in dollars per share)	$ (0.06)	$ 0.17
Net income (loss) per share, diluted (in dollars per share)	$ (0.06)	$ 0.17

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (1,476)	$ 7,753
Other comprehensive income (loss):
Currency translation adjustments		2,228	3,869
Deferred gain on hedging activity, net of tax	[1]	494	483
Pension activity, net of tax	[2]	(7)	(5)
Total comprehensive income		1,239	12,100
Comprehensive income attributable to non-controlling interests		(646)	(1,869)
Comprehensive income attributable to Aegion Corporation		$ 593	$ 10,231
[1]	Amounts presented net of tax of $177 and $321 for the quarters ended March 31, 2018 and 2017, respectively.
[2]	Amounts presented net of tax of $(2) and $(1) for the quarters ended March 31, 2018 and 2017, respectively.

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Unaudited) - Parenthetical - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Deferred gain on hedging activity, tax	$ 177	$ 321
Pension activity, tax (benefit) expense	$ (2)	$ (1)

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 87,173	$ 105,717
Restricted cash	1,858	1,839
Receivables, net of allowances of $7,034 and $5,775, respectively	177,364	201,570
Retainage	31,327	33,002
Contract assets	81,052	75,371
Inventories	66,263	63,969
Prepaid expenses and other current assets	30,037	35,282
Assets held for sale	72,683	70,314
Total current assets	547,757	587,064
Property, plant & equipment, less accumulated depreciation	108,045	109,040
Other assets
Goodwill	261,018	260,715
Intangible assets, less accumulated amortization	128,821	132,345
Deferred income tax assets	1,725	1,666
Other assets	17,179	16,269
Total other assets	408,743	410,995
Total Assets	1,064,545	1,107,099
Current liabilities
Accounts payable	61,361	70,611
Accrued expenses	83,460	92,011
Contract liabilities	45,139	51,597
Current maturities of long-term debt	26,557	26,555
Liabilities held for sale	14,731	20,900
Total current liabilities	231,248	261,674
Long-term debt, less current maturities	315,629	318,240
Deferred income tax liabilities	9,214	9,211
Other non-current liabilities	13,403	12,918
Total liabilities	569,494	602,043
(See Commitments and Contingencies: Note 10)
Equity
Preferred stock, undesignated, $.10 par – shares authorized 2,000,000; none outstanding	0	0
Common stock, $.01 par – shares authorized 125,000,000; shares issued and outstanding 32,467,823 and 32,462,542, respectively	325	325
Additional paid-in capital	129,237	140,749
Retained earnings	384,207	386,008
Accumulated other comprehensive loss	(30,174)	(32,836)
Total stockholders’ equity	483,595	494,246
Non-controlling interests	11,456	10,810
Total equity	495,051	505,056
Total Liabilities and Equity	$ 1,064,545	$ 1,107,099

Consolidated Balance Sheets (U6

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 7,034	$ 5,775
Preferred stock, undesignated, par (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, undesignated, shares authorized	2,000,000	2,000,000
Preferred stock, undesignated, shares outstanding	0	0
Common stock, par (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issues	32,467,823	32,462,542
Common stock, shares outstanding	32,467,823	32,462,542

Consolidated Statements of Equi

Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non- Controlling Interests	Restricted Stock Units	Restricted Stock UnitsCommon Stock	Performance UnitsCommon Stock
Balance (in shares) at Dec. 31, 2016		33,956,304
Balance at Dec. 31, 2016	$ 576,183	$ 340	$ 166,598	$ 455,062	$ (53,500)	$ 7,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	7,753			5,871		1,882
Issuance of shares pursuant to restricted stock units (in shares)								62,279	49,672
Issuance of shares pursuant to restricted stock units							$ 1	$ 1
Forfeitures of restricted shares (in shares)		(1,084)
Shares repurchased and retired (in shares)		(462,317)
Shares repurchased and retired	(10,508)	$ (5)	(10,503)
Equity-based compensation expense	3,096		3,096
Currency translation adjustment and derivative transactions, net	4,347				4,360	(13)
Balance (in shares) at Mar. 31, 2017		33,604,854
Balance at Mar. 31, 2017	580,872	$ 336	159,191	460,933	(49,140)	9,552
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment (see Revenues: Note 3)	$ 268			268
Balance (in shares) at Dec. 31, 2017	32,462,542	32,462,542
Balance at Dec. 31, 2017	$ 505,056	$ 325	140,749	386,008	(32,836)	10,810
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(1,476)			(2,069)		593
Issuance of shares pursuant to restricted stock units (in shares)								275,384	296,909
Issuance of shares pursuant to restricted stock units	3							$ 3	$ 3
Issuance of shares pursuant to deferred stock unit awards (in shares)		4,568
Shares repurchased and retired (in shares)		(571,580)
Shares repurchased and retired	(13,676)	$ (6)	(13,670)
Equity-based compensation expense	2,158		2,158
Currency translation adjustment and derivative transactions, net	$ 2,715				2,662	53
Balance (in shares) at Mar. 31, 2018	32,467,823	32,467,823
Balance at Mar. 31, 2018	$ 495,051	$ 325	$ 129,237	$ 384,207	$ (30,174)	$ 11,456

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (1,476)	$ 7,753
Adjustments to reconcile to net cash provided by (used in) operating activities:
Depreciation and amortization	9,554	11,852
Gain on sale of fixed assets	(105)	(116)
Equity-based compensation expense	2,158	3,096
Deferred income taxes	(38)	5,533
Non-cash restructuring charges	2,408	42
Loss on foreign currency transactions	315	378
Other	561	(62)
Changes in operating assets and liabilities (net of acquisitions):
Receivables net, retainage and contract assets	16,584	(30,257)
Inventories	(2,223)	(3,491)
Prepaid expenses and other assets	6,657	5,351
Accounts payable and accrued expenses	(24,729)	(9,988)
Contract liabilities	(8,860)	(18,078)
Other operating	470	300
Net cash provided by (used in) operating activities	1,276	(27,687)
Cash flows from investing activities:
Capital expenditures	(5,189)	(3,907)
Proceeds from sale of fixed assets	284	165
Patent expenditures	(48)	(289)
Other acquisition activity, net of cash acquired	0	(9,045)
Net cash used in investing activities	(4,953)	(13,076)
Cash flows from financing activities:
Repurchase of common stock	(13,670)	(10,508)
Payment of contingent consideration	0	(500)
Credit facility amendment fees	(1,093)	0
Principal payments on notes payable	568	0
Proceeds from line of credit, net	5,000	10,000
Principal payments on long-term debt	(6,563)	(4,375)
Net cash used in financing activities	(16,894)	(5,383)
Effect of exchange rate changes on cash	1,870	929
Net decrease in cash, cash equivalents and restricted cash for the period	(18,701)	(45,217)
Cash, cash equivalents and restricted cash, beginning of year	108,545	134,392
Cash, cash equivalents and restricted cash, end of period	89,844	89,175
Cash, cash equivalents and restricted cash associated with assets held for sale, end of period	813	0
Cash, cash equivalents and restricted cash, end of period	$ 89,031	$ 89,175

Accounting Policies

Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Accounting Policies	ACCOUNTING POLICIES On January 1, 2018, the Company adopted FASB ASC 606, Revenue from Contracts with Customers (“FASB ASC 606”). See Note 3 for further information. Other than the adoption of FASB ASC 606, t here were no material changes in accounting policies from those disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Foreign Currency Translation For the Company’s international subsidiaries, the local currency is generally the functional currency. Assets and liabilities of these subsidiaries are translated into U.S. dollars using rates in effect at the balance sheet date while revenues and expenses are translated into U.S. dollars using average exchange rates. The cumulative translation adjustment resulting from changes in exchange rates are included in the Consolidated Balance Sheets as a component of “Accumulated other comprehensive loss” in total stockholders’ equity. The Company’s accumulated other comprehensive loss is comprised of three main components: (i) currency translation; (ii) derivatives; and (iii) gains and losses associated with the Company’s defined benefit plan in the United Kingdom (in thousands): March 31, 2018 December 31, 2017 Currency translation adjustments $ (33,928 ) $ (35,928 ) Derivative hedging activity 4,007 3,336 Pension activity (253 ) (244 ) Total accumulated other comprehensive loss $ (30,174 ) $ (32,836 ) Net foreign exchange transaction losses of $0.3 million and $0.4 million in the first quarters of 2018 and 2017 , respectively, are included in “Other expense” in the Consolidated Statements of Operations. Taxation The Company provides for estimated income taxes payable or refundable on current year income tax returns as well as the estimated future tax effects attributable to temporary differences and carryforwards, based upon enacted tax laws and tax rates, and in accordance with FASB ASC 740, Income Taxes (“FASB ASC 740”). FASB ASC 740 also requires that a valuation allowance be recorded against any deferred tax assets that are not likely to be realized in the future. The determination is based on the Company’s ability to generate future taxable income and, at times, is dependent on its ability to implement strategic tax initiatives to ensure full utilization of recorded deferred tax assets. Should the Company not be able to implement the necessary tax strategies, it may need to record valuation allowances for certain deferred tax assets, including those related to foreign income tax benefits. Significant management judgment is required in determining the provision for income taxes, deferred tax assets and liabilities and any valuation allowances recorded against net deferred tax assets. As a result of the reduction in the U.S. corporate income tax rate from 35% to 21% under the Tax Cuts and Jobs Act (“TCJA”), FASB ASC 740 required the Company to remeasure its deferred tax assets and liabilities based on tax rates at which the balances are expected to reverse in the future. The provisional amount recorded for the remeasurement of the Company’s deferred tax balances resulted in no adjustment to income tax expense in 2017 or 2018. The remeasurement of the deferred tax assets gave rise to an additional income tax expense of $5.1 million in 2017, which was offset by an equal reduction in the valuation allowance of $5.1 million . The Company continues to analyze certain aspects of the TCJA, including consideration of additional forthcoming technical guidance, which could potentially affect the measurement of these balances or potentially give rise to new deferred tax amounts. In 2017, in connection with its initial analysis of the TCJA, the Company recorded a provisional estimated net income tax expense of $2.4 million , which consisted of a charge of $10.4 million for the deemed mandatory repatriation less $7.1 million related to the release of deferred tax liabilities on unremitted foreign earnings and $0.9 million associated with other TCJA related impacts. On December 22, 2017, the SEC issued guidance under Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, (“SAB 118”), directing a taxpayer to consider the impact of the U.S. legislation as “provisional” when it does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for income tax effects of the TCJA. In accordance with SAB 118, the additional estimated income tax of $2.4 million represented the Company’s best estimate at the time it was made, but also understanding that the provisional amount is subject to further adjustments under SAB 118. There were no changes to this estimate during the first quarter of 2018. The Company continues to refine provisional balances, and adjustments may be made under SAB 118 during the measurement period as a result of future changes in interpretation, issuance of additional regulatory guidance from the U.S. federal and state tax authorities, or its own assumption changes. All accounting will be completed within the one-year measurement period allowed under SAB 118. The ultimate impact of the TCJA may differ from the current provisional amounts and the adjustments could be material. Earnings per Share Earnings per share have been calculated using the following share information: Quarters Ended March 31, 2018 2017 Weighted average number of common shares used for basic EPS 32,483,963 33,819,331 Effect of dilutive stock options and restricted and deferred stock unit awards — 685,257 Weighted average number of common shares and dilutive potential common stock used in dilutive EPS 32,483,963 34,504,588 The Company excluded 710,173 stock options and restricted and deferred stock units for the quarter ended March 31, 2018 from the diluted earnings per share calculation for the Company’s common stock because of the reported net loss for the period. The Company excluded 77,807 stock options for the quarter ended March 31, 2017 from the diluted earnings per share calculation for the Company’s common stock because they were anti-dilutive as their exercise prices were greater than the average market price of common shares for the period. Cash, Cash Equivalents and Restricted Cash The Company classifies highly liquid investments with original maturities of 90 days or less as cash equivalents. Recorded book values are reasonable estimates of fair value for cash and cash equivalents. Cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets and Consolidated Statements of Cash Flows are as follows (in thousands): Balance sheet data March 31, December 31, Cash and cash equivalents (1) $ 87,173 $ 105,717 Restricted cash 1,858 1,839 Cash, cash equivalents and restricted cash $ 89,031 $ 107,556 __________________________ (1) Amounts exclude $0.8 million and $1.0 million of cash and cash equivalents classified as held for sale at March 31, 2018 and December 31, 2017, respectively. Restricted cash held in escrow primarily relates to funds reserved for legal requirements, deposits made in lieu of retention on specific projects performed for municipalities and state agencies, or advance customer payments and compensating balances for bank undertakings in Europe. Restricted cash related to operations is similar to retainage, and is, therefore, classified as a current asset, consistent with the Company’s policy on retainage. Investments in Variable Interest Entities The Company evaluates all transactions and relationships with variable interest entities (“VIE”) to determine whether the Company is the primary beneficiary of the entities in accordance with FASB ASC 810, Consolidation . There were no changes in the Company’s VIEs during the quarter ended March 31, 2018 . Financial data for consolidated variable interest entities are summarized in the following tables (in thousands): Balance sheet data March 31, (1) December 31, (2) Current assets $ 41,877 $ 42,732 Non-current assets 26,725 26,346 Current liabilities 12,275 12,449 Non-current liabilities 28,371 30,675 __________________________ (1) Amounts include $25.2 million of assets and $9.3 million of liabilities classified as held for sale relating to our pipe coating and insulation joint venture in Louisiana, Bayou Wasco Insulation, LLC. See Note 5. (2) Amounts include $25.4 million of assets and $9.8 million of liabilities classified as held for sale relating to our pipe coating and insulation joint venture in Louisiana, Bayou Wasco Insulation, LLC. See Note 5. Quarters Ended March 31, Income statement data (1) 2018 2017 (1) Revenue $ 16,051 $ 34,061 Gross profit 3,310 5,530 Net income attributable to Aegion Corporation 1,248 1,272 __________________________ (1) During the first quarter of 2017, increased activity was primarily driven from our joint venture in Louisiana, which performed work on a large deepwater pipe coating and insulation project. Newly Issued Accounting Pronouncements In February 2018, the FASB issued Accounting Standards Update No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which permits a company to reclassify the income tax effects of the TCJA on items within accumulated other comprehensive income to retained earnings. The guidance is effective for the Company’s fiscal year beginning January 1, 2019, including interim periods within that fiscal year. Companies may adopt the new guidance using one of two transition methods: (i) retrospective to each period (or periods) in which the income tax effects are recognized, or (ii) at the beginning of the period of adoption. The Company is currently evaluating the effect the guidance will have on its consolidated financial statements. In August 2017, the FASB issued Accounting Standards Update No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities , which amends the recognition and presentation requirements for hedge accounting activities. The standard improves the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and reduces the complexity of applying hedge accounting. This new guidance is effective for the Company’s fiscal year beginning January 1, 2019, but the Company early-adopted this standard, effective January 1, 2018. The adoption of this standard did not have a material impact on its consolidated financial statements. In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash , which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. As a result, restricted cash is included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This new guidance was effective for the Company’s fiscal year beginning January 1, 2018 and applied retrospectively. The Company’s adoption of this standard, effective January 1, 2018, did not have a material impact on its consolidated financial statements, other than the classification of restricted cash on the Consolidated Statement of Cash Flows. In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which addresses diversity in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard was effective for the Company’s fiscal year beginning January 1, 2018, the adoption of which did not have a material impact on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) , that requires lessees to present right-of-use assets and lease liabilities on the balance sheet for all leases with lease terms longer than twelve months. The standard is effective for the Company’s fiscal year beginning January 1, 2019, including interim periods within that fiscal year. Early adoption is permitted, although the Company does not intend to do so. The Company intends to adopt the new guidance using the cumulative effect method, which would apply to all new lease contracts initiated on or after January 1, 2019. For existing lease contracts that have remaining obligations as of January 1, 2019, the difference between the recognition criteria in the new guidance and the Company’s current practices would be recognized using a cumulative effect adjustment to the opening balance of retained earnings. In early 2017, the Company identified a project manager as well as a cross-functional implementation team responsible for identifying and assessing the impact on its lease contracts. During 2017, the implementation team began the assessment phase, which included data retrieval from the Company’s key third-party lease administration vendors and the identification of the Company’s known lease contracts throughout the world. During the first half of 2018, the Company will: (i) perform an analysis of the new standard on its current lease contracts as well as other existing arrangements to determine if they qualify for lease accounting under the new standard; and (ii) identify potential changes to business processes, systems and controls to support recognition and disclosure under the new standard. In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which replaces revenue recognition requirements regarding contracts with customers to transfer goods or services with a single revenue recognition model for recognizing revenue. Under the new guidance, entities are required to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides a five-step analysis to be performed on transactions to determine when and how revenue is recognized. The Company adopted this standard, effective January 1, 2018, using the modified retrospective transition method. See Note 3.

General

General	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	GENERAL The accompanying unaudited consolidated financial statements of Aegion Corporation and its subsidiaries (collectively, “Aegion” or the “Company”) reflect all adjustments (consisting only of normal recurring adjustments) that are, in the opinion of management, necessary for a fair statement of the Company’s financial position, results of operations and cash flows for the dates and periods presented. Results for interim periods are not necessarily indicative of the results to be expected during the remainder of the current year or for any future period. All significant intercompany related accounts and transactions have been eliminated in consolidation. The Consolidated Balance Sheet as of December 31, 2017, which is derived from the audited consolidated financial statements, and the interim unaudited consolidated financial statements included herein have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), the requirements of Form 10-Q and Article 10 of Regulation S-X and, consequently, do not include all information or footnotes required by GAAP for complete financial statements or all the disclosures normally made in an Annual Report on Form 10-K. Accordingly, the unaudited consolidated financial statements included herein should be read in conjunction with the audited consolidated financial statements and footnotes included in the Company’s 2017 Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 1, 2018. Acquisitions/Strategic Initiatives/Divestitures 2017 Restructuring On July 28, 2017, the Company’s board of directors approved a realignment and restructuring plan (the “2017 Restructuring”). As part of the 2017 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. These decisions reflected the Company’s: (a) desire to reduce further its exposure in the North American upstream oil and gas markets; (b) assessment of its ability to drive sustainable, profitable growth in the non-pipe fiber reinforced polymer ( “FRP” ) contracting market in North America; and (c) assessment of continuing weak conditions in the Canadian oil and gas markets. See Note 4. Infrastructure Solutions Segment (“Infrastructure Solutions”) On March 1, 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 September 2017, the Company organized Aegion South Africa Proprietary Limited, a joint venture in South Africa between Aegion International Holdings Limited, a subsidiary of the Company (“Aegion International”), and Robor Proprietary Limited (“Robor”), for the purpose of providing Aegion’s Corrosion Protection and Infrastructure Solutions products and services to sub-Saharan Africa. Aegion International owns sixty percent ( 60% ) of the joint venture and Robor owns the remaining forty percent ( 40% ). On July 28, 2017, the Company’s board of directors approved a plan to divest Bayou. Accordingly, the Company has classified Bayou’s assets and liabilities as held for sale on the Consolidated Balance Sheets at March 31, 2018 and December 31, 2017. See Note 5. Purchase Price Accounting During the first quarter of 2018, the Company finalized its accounting for Environmental Techniques with no significant adjustments recorded. The goodwill and definite-lived intangible assets associated with the Environmental Techniques acquisition is not deductible for tax purposes. Environmental Techniques made the following contributions to the Company’s revenues and profits (in thousands): Quarters Ended March 31, 2018 2017 Revenues $ 2,260 $ 451 Net income (loss) 11 (102 ) The following pro-forma summary presents combined information of the Company as if the Environmental Techniques acquisition had occurred at the beginning of the year preceding its acquisition (in thousands, except earnings per share): Quarter Ended March 31, 2017 Revenues $ 326,057 Net income attributable to Aegion Corporation (1) 5,698 Diluted earnings per share $ 0.17 _____________________ (1) Includes pro-forma adjustments for depreciation and amortization associated with acquired tangible and intangible assets, as if those assets were recorded at the beginning of the year preceding the acquisition date. The following table summarizes the fair value of identified assets and liabilities of Environmental Techniques at its acquisition date (in thousands): Environmental Techniques Receivables and cost and estimated earnings in excess of billings $ 801 Inventories 1,281 Prepaid expenses and other current assets 93 Property, plant and equipment 2,147 Identified intangible assets 1,869 Deferred income tax assets 124 Accounts payable (1,025 ) Accrued expenses (186 ) Deferred income tax liabilities (413 ) Total identifiable net assets $ 4,691 Total consideration recorded $ 8,046 Less: total identifiable net assets 4,691 Final purchase price goodwill $ 3,355

Revenues

Revenues	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenues	REVENUES On January 1, 2018, the Company adopted FASB ASC 606 for all contracts that were not completed using the modified retrospective transition method. The Company recognized the cumulative effect of initially applying FASB ASC 606 as an adjustment to the opening balance of retained earnings. Prior period information has not been restated and continues to be reported under the accounting standards in effect for those periods. The Company recorded a net reduction to opening retained earnings of $0.3 million as of January 1, 2018 due to the cumulative impact of adopting FASB ASC 606, with the impact primarily related to royalty license fee revenues. The impact to revenues for the quarter ended March 31, 2018 was a decrease of $0.1 million as a result of applying FASB ASC 606. Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer, and is the unit of account in FASB ASC 606. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. For contracts in which construction, engineering and installation services are provided, there is a single performance obligation as the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts and, therefore, not distinct. The bundle of goods and services represents the combined output for which the customer has contracted for. For product sales contracts with multiple performance obligations where each product is distinct, the Company allocates the contract’s transaction price to each performance obligation using its best estimate of the standalone selling price of each distinct good in the contract. For royalty license agreements whereby intellectual property is transferred to the customer, there is a single performance obligation as the license is not separately identifiable from the other goods and services in the contract. The Company’s performance obligations are satisfied over time as work progresses or at a point in time. Revenues from products and services transferred to customers over time accounted for 95.0% and 92.9% of revenues for the quarters ended March 31, 2018 and 2017, respectively. Revenues from construction, engineering and installation services are recognized over time using an input measure (e.g., costs incurred to date relative to total estimated costs at completion) to measure progress toward satisfying performance obligations. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Contract costs include labor, material, overhead and, when appropriate, general and administrative expenses. Revenues from royalty license arrangements are recognized either at contract inception when the license is transferred or when the royalty has been earned, depending on whether the contract contains fixed consideration. Revenues from stand-alone product sales are recognized at a point in time, when control of the product is transferred to the customer. Revenues from these types of contracts accounted for 5.0% and 7.1% for the quarters ended March 31, 2018 and 2017, respectively. On March 31, 2018, the Company had $720.4 million of remaining performance obligations. The Company estimates that approximately $711.1 million , or 98.7% , of the remaining performance obligations at March 31, 2018 will be realized as revenues in the next 12 months. Contract Estimates Accounting for long-term contracts involves the use of various techniques to estimate total contract revenue and costs. For long-term contracts, the Company estimates the profit on a contract as the difference between the total estimated revenue and expected costs to complete a contract, and recognizes that profit over the life of the contract. Contract estimates are based on various assumptions to project the outcome of future events that sometimes span multiple years. These assumptions include labor productivity and availability; the complexity of the work to be performed; the cost and availability of materials; the performance of subcontractors; and the availability and timing of funding from the customer. The Company’s contracts do not typically contain variable consideration or other provisions that increase or decrease the transaction price. In rare situations where the transaction price is not fixed, the Company estimates variable consideration at the most likely amount to which it expects to be entitled. The Company includes estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. For royalty license agreements, the Company applies the sales-based and usage-based royalty exception and recognizes royalties at the later of: (i) when the subsequent sale or usage occurs; or (ii) the satisfaction or partial satisfaction of the performance obligation to which some or all of the sales-or usage-based royalty has been allocated. For contracts in which a portion of the transaction price is retained and paid after the good or service has been transferred to the customer, the Company does not recognize a significant financing component. The primary purpose of the retainage payment is often to provide the customer with assurance that the Company will perform its obligations under the contract, rather than to provide financing to the customer. The Company’s estimates of variable consideration and determination of whether to include estimated amounts in the transaction price are based largely on an assessment of anticipated performance and all information (historical, current and forecasted) that is reasonably available. Revenue by Category The following tables summarize revenues by segment and geography (in thousands): Quarter Ended March 31, 2018 Infrastructure Solutions Corrosion Protection Energy Services Total Primary geographic region: United States $ 93,845 $ 63,858 $ 92,329 $ 250,032 Canada 12,269 16,570 — 28,839 Europe 13,143 2,866 — 16,009 Other foreign 15,170 14,811 — 29,981 Total revenues $ 134,427 $ 98,105 $ 92,329 $ 324,861 Quarter Ended March 31, 2017 Infrastructure Solutions Corrosion Protection Energy Services Total Primary geographic region: United States $ 93,904 $ 90,903 $ 72,917 $ 257,724 Canada 10,817 16,010 — 26,827 Europe 12,960 3,185 — 16,145 Other foreign 11,187 13,292 — 24,479 Total revenues $ 128,868 $ 123,390 $ 72,917 $ 325,175 The following tables summarize revenues by segment and contract type (in thousands): Quarter Ended March 31, 2018 Infrastructure Solutions Corrosion Protection Energy Services Total Contract type: Fixed fee $ 125,263 $ 77,901 $ 5,757 $ 208,921 Time and materials — 13,107 86,572 99,679 Product sales 9,144 7,097 — 16,241 License fees 20 — — 20 Total revenues $ 134,427 $ 98,105 $ 92,329 $ 324,861 Quarter Ended March 31, 2017 Infrastructure Solutions Corrosion Protection Energy Services Total Contract type: Fixed fee $ 118,998 $ 98,520 $ 1,507 $ 219,025 Time and materials — 11,476 71,410 82,886 Product sales 9,714 13,394 — 23,108 License fees 156 — — 156 Total revenues $ 128,868 $ 123,390 $ 72,917 $ 325,175 Contract Balances The timing of revenue recognition, billings and cash collections results in billed accounts receivable, contract assets and contract liabilities on the Consolidated Balance Sheets. Contract assets represent work performed that could not be billed either due to contract stipulations or the required contractual documentation has not been finalized. Substantially all unbilled amounts are expected to be billed and collected within one year. For fixed fee and time-and-materials based contracts, amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. For some royalty license arrangements, amounts are billed over the license term as quarterly royalty amounts are determined. This results in contract assets as the Company recognizes revenue for the license when the license is transferred to the customer at contract inception. The Company’s contract liabilities consist of advance payments and billings in excess of revenue recognized and deferred revenue. The Company’s contract assets and contract liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period. Advance payments, billings in excess of revenue recognized and deferred revenue are each classified as current. Net contract assets (liabilities) consisted of the following (in thousands): March 31, 2018 December 31, 2017 Contract assets – current $ 81,052 $ 75,371 Contract assets – noncurrent (1) 11 — Contract liabilities – current (45,139 ) (51,597 ) Net contract assets (liabilities) $ 35,924 $ 23,774 __________________________ (1) Included in “Other assets” on the Consolidated Balance Sheets. Included in the change of total net contract assets (liabilities) was a $5.7 million increase in contract assets, primarily related to the timing between work performed on open contracts and contractual billing terms, and a $6.5 million decrease in contract liabilities, primarily related to the timing of customer advances on certain contracts. Substantially all of the $51.6 million and $62.7 million contract liabilities balances at December 31, 2017 and December 31, 2016, respectively, were recognized in revenues during the first quarters of 2018 and 2017, respectively. Impairment losses recognized on receivables and contract assets were not material during the first quarters of 2018 and 2017.

Restructuring

Restructuring	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Restructuring	RESTRUCTURING 2017 Restructuring On July 28, 2017, the Company’s board of directors approved the 2017 Restructuring. As part of the 2017 Restructuring, the Company announced plans to: (i) divest 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. These decisions reflected the Company’s: (a) desire to reduce further its exposure in the North American upstream oil and gas markets; (b) assessment of its ability to drive sustainable, profitable growth in the non-pipe FRP contracting market in North America; and (c) assessment of continuing weak conditions in the Canadian oil and gas markets. During the first quarter of 2018, total pre-tax 2017 Restructuring charges recorded were $5.2 million ( $4.7 million post-tax) and consisted of employee severance, retention, extension of benefits, employment assistance programs, early lease and contract termination and other restructuring costs associated with the restructuring efforts described above. Total pre-tax 2017 Restructuring charges since inception were $29.0 million ( $25.3 million post-tax) and consisted of non-cash charges totaling $12.5 million and cash charges totaling $16.5 million . The Company reduced headcount by approximately 310 employees as a result of these actions. The Company expects to incur additional charges of $2 million to $5 million , most of which are expected to be cash charges in 2018. During the first quarter of 2018, the Company recorded pre-tax expenses related to the 2017 Restructuring as follows (in thousands): Infrastructure Solutions Corrosion Protection Total Severance and benefit related costs $ 865 $ 206 $ 1,071 Lease and contract termination costs 528 150 678 Relocation and other moving costs 40 — 40 Other restructuring costs (1) 2,100 1,355 3,455 Total pre-tax restructuring charges (2) $ 3,533 $ 1,711 $ 5,244 __________________________ (1) Includes charges primarily related to certain wind-down costs, allowances for accounts receivable and other restructuring-related costs in connection with exiting non-pipe-related contract applications for the Tyfo ® system in North America. (2) Includes $0.6 million of corporate-related restructuring charges that have been allocated to the Infrastructure Solutions and Corrosion Protection reportable segments. 2017 Restructuring costs related to severance, other termination benefit costs and early lease and contract termination costs were $1.8 million for the quarter ended March 31, 2018 and are reported on a separate line in the Consolidated Statements of Operations. The following table summarizes all charges related to the 2017 Restructuring recognized in the quarter ended March 31, 2018 as presented in their affected line in the Consolidated Statements of Operations (in thousands): Infrastructure Solutions Corrosion Protection Total (1) Operating expenses $ 2,100 $ 1,355 $ 3,455 Restructuring and related charges 1,433 356 1,789 Total pre-tax restructuring charges $ 3,533 $ 1,711 $ 5,244 __________________________ (1) Total pre-tax restructuring charges include cash charges of $2.8 million and non-cash charges of $2.4 million . Cash charges consist of charges incurred during the quarter that will be settled in cash, either during the current period or future periods. The following table summarizes the 2017 Restructuring activity during the first quarter of 2018 (in thousands): Reserves at December 31, 2017 2018 Foreign Currency Translation Utilized in 2018 Reserves at Cash (1) Non-Cash Severance and benefit related costs $ 3,864 $ 1,071 $ 20 $ 2,305 $ — $ 2,650 Lease and contract termination costs 650 678 — 793 — 535 Relocation and other moving costs — 40 — 40 — — Other restructuring costs 675 3,455 — 1,272 2,408 450 Total pre-tax restructuring charges $ 5,189 $ 5,244 $ 20 $ 4,410 $ 2,408 $ 3,635 __________________________ (1) Refers to cash utilized to settle charges during the first quarter of 2018.

Assets and Liabilities Held for

Assets and Liabilities Held for Sale	3 Months Ended
	Mar. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Assets and Liabilities Held for Sale	ASSETS AND LIABILITIES HELD FOR SALE On July 28, 2017, the Company’s board of directors approved a plan to sell the assets and liabilities of Bayou (see Note 1). It is probable that such sale will occur within one year of July 28, 2017. As a result, the relevant asset and liability balances are accounted for as held for sale and measured at the lower of carrying value or fair value less cost to sell. No impairment charges were recorded as the net carrying value approximated or was less than management’s current expectation of fair value less cost to sell. In the event the Company is unable to sell the assets and liabilities of Bayou or sells them at a price or on terms that are less favorable, or at a higher cost than currently anticipated, the Company could incur impairment charges or a loss on disposal. The following table provides the components of assets and liabilities held for sale (in thousands): March 31, December 31, Assets held for sale: Current assets Cash and cash equivalents $ 813 $ 989 Receivables, net 8,143 6,368 Contract assets 1,371 1,299 Inventories 3,541 3,727 Prepaid expenses and other current assets 763 827 Total current assets 14,631 13,210 Property, plant & equipment, less accumulated depreciation 54,835 53,887 Identified intangible assets, less accumulated amortization 3,217 3,217 Total assets held for sale $ 72,683 $ 70,314 Liabilities held for sale: Current liabilities Accounts payable $ 2,249 $ 5,763 Accrued expenses 1,543 1,805 Contract liabilities 3,076 5,478 Total current liabilities 6,868 13,046 Long-term debt 7,757 7,757 Other non-current liabilities 106 97 Total liabilities held for sale $ 14,731 $ 20,900

Goodwill and Identified Intangi

Goodwill and Identified Intangible Assets	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Identified Intangible Assets	GOODWILL AND INTANGIBLE ASSETS Goodwill The following table presents a reconciliation of the beginning and ending balances of the Company’s goodwill (in thousands): Infrastructure Corrosion Energy Total Balance, December 31, 2017: Goodwill, gross $ 246,486 $ 74,369 $ 80,246 $ 401,101 Accumulated impairment losses (61,459 ) (45,400 ) (33,527 ) (140,386 ) Goodwill, net 185,027 28,969 46,719 260,715 2018 Activity: Foreign currency translation 572 (269 ) — 303 Balance, March 31, 2018: Goodwill, gross 247,058 74,100 80,246 401,404 Accumulated impairment losses (61,459 ) (45,400 ) (33,527 ) (140,386 ) Goodwill, net $ 185,599 $ 28,700 $ 46,719 $ 261,018 Intangible Assets Intangible assets consisted of the following (in thousands): March 31, 2018 December 31, 2017 Weighted Average Useful Lives (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount License agreements 10.8 $ 4,511 $ (3,667 ) $ 844 $ 4,497 $ (3,623 ) $ 874 Leases 2.8 796 (556 ) 240 796 (534 ) 262 Trademarks 10.2 15,494 (6,508 ) 8,986 15,464 (6,184 ) 9,280 Non-competes 2.0 1,201 (1,075 ) 126 1,197 (1,048 ) 149 Customer relationships 9.7 160,543 (59,638 ) 100,905 160,423 (56,907 ) 103,516 Patents and acquired technology 6.0 39,100 (21,380 ) 17,720 39,285 (21,021 ) 18,264 $ 221,645 $ (92,824 ) $ 128,821 $ 221,662 $ (89,317 ) $ 132,345 Amortization expense was $3.5 million and $4.3 million for the quarters ended March 31, 2018 and 2017 , respectively. Estimated amortization expense by year is as follows (in thousands): 2018 $ 13,770 2019 13,572 2020 13,518 2021 13,335 2022 13,335

Long-Term Debt and Credit Facil

Long-Term Debt and Credit Facility	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt and Credit Facility	LONG-TERM DEBT AND CREDIT FACILITY Financing Arrangements Long-term debt consisted of the following (in thousands): March 31, 2018 December 31, 2017 Term note, due February 27, 2023, annualized rates of 3.98% and 3.60%, respectively $ 301,875 $ 308,437 Line of credit, 3.82% and 3.50%, respectively 43,000 38,000 Other notes with interest rates from 3.3% to 7.8% 330 875 Subtotal 345,205 347,312 Less – Current maturities of long-term debt 26,557 26,555 Less – Unamortized loan costs 3,019 2,517 Total $ 315,629 $ 318,240 In October 2015, the Company entered into an amended and restated $650.0 million senior secured credit facility with a syndicate of banks. On February 27, 2018, the Company amended this facility (the “amended Credit Facility”). Bank of America, N.A. served as the sole administrative agent and U.S. Bank National Association, PNC Bank, National Association and Compass Bank acted as co-syndication agents. Merrill Lynch Pierce Fenner & Smith Incorporated, U.S. Bank National Association, PNC Capital Markets, LLC and Compass Bank acted as joint lead arrangers and joint book managers in the syndication of the amended Credit Facility. The amended Credit Facility consists of a $300.0 million five -year revolving line of credit and a $308.4 million five -year term loan facility. Interest terms from the Company’s original credit facility did not change under the amendment. The amended Credit Facility also: (i) extended the expiration date of the original credit facility and the amortization period for the term loan facility from October 2020 to February 2023; (ii) approved the sale of Bayou; and (iii) updated the defined terms to allow for the add-back of certain charges related to the 2017 Restructuring when calculating the Company’s compliance with the financial covenants. In the event of the sale of Bayou, the net cash proceeds are required to be applied first against any outstanding borrowings on the revolving line of credit. Additionally, upon any such sale, the maximum aggregate principal amount of the revolving line of credit will be permanently reduced from $300.0 million to $275.0 million . The Company paid expenses of $2.4 million associated with the amended Credit Facility, $0.9 million related to up-front lending fees and $1.5 million related to third-party arranging fees and expenses, the latter of which was recorded in “Interest expense” in the Consolidated Statement of Operations during the first quarter of 2018. In addition, the Company had $2.4 million in unamortized loan costs associated with the original Credit Facility, of which $0.2 million was written off and recorded in “Interest expense” in the Consolidated Statement of Operations during the first quarter of 2018. Generally, interest is charged on the principal amounts outstanding under the amended Credit Facility at the British Bankers Association LIBOR rate plus an applicable rate ranging from 1.25% to 2.25% depending on the Company’s consolidated leverage ratio. The Company can also opt for an interest rate equal to a base rate (as defined in the credit documents) plus an applicable rate, which also is based on the Company’s consolidated leverage ratio. The applicable LIBOR borrowing rate (LIBOR plus Company’s applicable rate) as of March 31, 2018 was approximately 3.96% . The Company’s indebtedness at March 31, 2018 consisted of $301.9 million outstanding from the $308.4 million term loan under the amended Credit Facility, $43.0 million on the line of credit under the amended Credit Facility and $0.3 million of third-party notes and bank debt. Additionally, the Company had $7.8 million of debt held by a joint venture (representing funds loaned by its joint venture partner) listed as held for sale at March 31, 2018 related to the planned sale of Bayou. During the first quarter of 2018, the Company borrowed $5.0 million on the line of credit for domestic working capital needs. As of March 31, 2018 , the Company had $31.1 million in letters of credit issued and outstanding under the amended Credit Facility. Of such amount, $13.4 million was collateral for the benefit of certain of our insurance carriers and $17.7 million was for letters of credit or bank guarantees of performance or payment obligations of foreign subsidiaries. The Company’s indebtedness at December 31, 2017 consisted of $308.4 million outstanding from the term loan under the Credit Facility, $38.0 million on the line of credit under the Credit Facility and $0.9 million of third-party notes and bank debt. Additionally, the Company had $7.7 million of debt held by a joint venture (representing funds loaned by its joint venture partner) listed as held for sale at December 31, 2017 related to the planned sale of Bayou. At March 31, 2018 and December 31, 2017, the estimated fair value of the Company’s long-term debt was approximately $344.6 million and $356.0 million , respectively. Fair value was estimated using market rates for debt of similar risk and maturity and a discounted cash flow model, which are based on Level 3 inputs as defined in Note 12. In October 2015, the Company entered into an interest rate swap agreement for a notional amount of $262.5 million , which is set to expire in October 2020. The notional amount of this swap mirrors the amortization of a $262.5 million portion of the Company’s $350.0 million term loan drawn from the original Credit Facility. The swap requires the Company to make a monthly fixed rate payment of 1.46% calculated on the amortizing $262.5 million notional amount, and provides for the Company to receive a payment based upon a variable monthly LIBOR interest rate calculated on the same amortizing $262.5 million notional amount. The receipt of the monthly LIBOR-based payment offsets a variable monthly LIBOR-based interest cost on a corresponding $262.5 million portion of the Company’s term loan from the original Credit Facility. After considering the impact of the interest rate swap agreement, the effective borrowing rate on the Company’s term note as of March 31, 2018 was approximately 3.69% . This interest rate swap is used to partially hedge the interest rate risk associated with the volatility of monthly LIBOR rate movement and is accounted for as a cash flow hedge. See Note 12. On March 12, 2018, the Company entered into an interest rate swap forward agreement that begins in October 2020 and expires in February 2023 to coincide with the amortization period of the amended Credit Facility. The swap requires the Company to make a monthly fixed rate payment of 2.937% calculated on the then amortizing $170.6 million notional amount, and provides for the Company to receive a payment based upon a variable monthly LIBOR interest rate calculated on the same amortizing $170.6 million notional amount. The receipt of the monthly LIBOR-based payment offsets a variable monthly LIBOR-based interest cost on a corresponding $170.6 million portion of the Company’s term loan from the amended Credit Facility. This interest rate swap is used to partially hedge the interest rate risk associated with the volatility of monthly LIBOR rate movement and is accounted for as a cash flow hedge. See Note 12. The amended Credit Facility is subject to certain financial covenants, including a consolidated financial leverage ratio and consolidated fixed charge coverage ratio. Subject to the specifically defined terms and methods of calculation as set forth in the amended Credit Facility’s credit agreement, the financial covenant requirements, as of each quarterly reporting period end, are defined as follows: • Consolidated financial leverage ratio compares consolidated funded indebtedness to amended Credit Facility defined income with a maximum amount not to exceed 3.75 to 1.00. At March 31, 2018 , the Company’s consolidated financial leverage ratio was 3.15 to 1.00 and, using the amended Credit Facility defined income, the Company had the capacity to borrow up to $68.2 million of additional debt. • Consolidated fixed charge coverage ratio compares amended Credit Facility defined income to amended Credit Facility defined fixed charges with a minimum permitted ratio of not less than 1.15 to 1.00. At March 31, 2018 , the Company’s fixed charge ratio was 1.44 to 1.00. At March 31, 2018 , the Company was in compliance with all of its debt and financial covenants as required under the amended Credit Facility.

Stockholders' Equity and Equity

Stockholders' Equity and Equity Compensation	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Stockholders' Equity and Equity Compensation	STOCKHOLDERS’ EQUITY AND EQUITY COMPENSATION Share Repurchase Plan Under the terms of the amended Credit Facility, the Company is authorized to purchase up to $30.0 million of shares of its common stock in open market purchases during 2018. In October 2017, the Company’s board of directors authorized the open market repurchase of up to $40.0 million of the Company’s common stock to be made during 2018, which authorization was reduced to $30 million in 2018 in connection with the execution of the amended Credit Facility. The Company began repurchasing shares under this program in January 2018. Once repurchased, the Company promptly retires such shares. The Company is also authorized to repurchase up to $10.0 million of the Company’s common stock in each calendar year in connection with the Company’s equity compensation programs for employees. The participants in the Company’s equity plans may surrender shares of common stock in satisfaction of tax obligations arising from the vesting of restricted stock, restricted stock unit awards and performance unit awards under such plans and in connection with the exercise of stock option awards. The deemed price paid is the closing price of the Company’s common stock on the Nasdaq Global Select Market on the date that the restricted stock, restricted stock unit or performance unit vests or the shares of the Company’s common stock are surrendered in exchange for stock option exercises. With regard to stock option awards, the option holder may elect a “net, net” exercise in connection with the exercise of employee stock options such that the option holder receives a number of shares equal to the built-in gain in the option shares divided by the market price of the Company’s common stock on the date of exercise, less a number of shares equal to the taxes due upon the exercise of the option divided by the market price of the Company’s common stock on the date of exercise. The shares of common stock surrendered for taxes due on the exercise of the option are deemed repurchased by the Company. During the first quarter of 2018, the Company acquired 353,831 shares of the Company’s common stock for $8.4 million ( $23.78 average price per share) through the open market repurchase program discussed above and 217,749 shares of the Company’s common stock for $5.3 million ( $24.14 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock units and performance units. Once repurchased, the Company immediately retired all such shares. During the first quarter of 2017, the Company acquired 366,914 shares of the Company’s common stock for $8.4 million ( $22.82 average price per share) through the open market repurchase program discussed above and 95,403 shares of the Company’s common stock for $2.1 million ( $22.37 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock, restricted stock units and performance units. Once repurchased, the Company immediately retired all such shares. Equity-Based Compensation Plans In April 2016, the Company’s stockholders approved the 2016 Employee Equity Incentive Plan, which was amended in 2017 by the First Amendment to the 2016 Employee Equity Incentive Plan (as amended, the “2016 Employee Plan”). The 2016 Employee Plan, which replaced the 2013 Employee Equity Incentive Plan, provides for equity-based compensation awards, including restricted shares of common stock, performance awards, stock options, stock units and stock appreciation rights. The 2016 Employee Plan is administered by the Compensation Committee of the board of directors, which determines eligibility, timing, pricing, amount and other terms or conditions of awards. As of March 31, 2018 , 796,023 shares of the Company’s common stock were available for issuance under the 2016 Employee Plan. In April 2016, the Company’s stockholders also approved the 2016 Non-Employee Director Equity Incentive Plan (the “2016 Director Plan”), which replaced the 2011 Non-Employee Director Equity Incentive Plan. The 2016 Director Plan provides for equity-based compensation awards, including non-qualified stock options and stock units. The board of directors administers the 2016 Director Plan and has the authority to establish, amend and rescind any rules and regulations related to the 2016 Director Plan. As of March 31, 2018 , 115,361 shares of the Company’s common stock were available for issuance under the 2016 Director Plan. Stock Awards Stock awards, which include shares of restricted stock, restricted stock units and performance stock units, are awarded from time to time to executive officers and certain key employees of the Company. Stock award compensation is recorded based on the award date fair value and charged to expense ratably through the requisite service period. The forfeiture of unvested restricted stock, restricted stock units and performance stock units causes the reversal of all previous expense to be recorded as a reduction of current period expense. A summary of the stock award activity is as follows: Quarter Ended Stock Awards Weighted Average Award Date Fair Value Outstanding at December 31, 2017 1,428,878 $ 21.53 Restricted stock units awarded 245,886 24.12 Performance stock units awarded 219,943 23.25 Restricted stock units distributed (275,384 ) 17.29 Performance stock units distributed (296,909 ) 21.55 Restricted stock units forfeited (12,207 ) 19.73 Performance stock units forfeited (11,801 ) 25.83 Outstanding at March 31, 2018 1,298,406 $ 23.19 Expense associated with stock awards was $2.1 million and $3.0 million for the quarters ended March 31, 2018 and 2017 , respectively. Unrecognized pre-tax expense of $18.1 million related to stock awards is expected to be recognized over the weighted average remaining service period of 2.23 years for awards outstanding at March 31, 2018 . Deferred Stock Unit Awards Deferred stock units are generally awarded to directors of the Company and represent the Company’s obligation to transfer one share of the Company’s common stock to the grantee at a future date and are generally fully vested on the date of grant. The expense related to the issuance of deferred stock units is recorded as of the date of the award. A summary of deferred stock unit activity is as follows: Quarter Ended Deferred Stock Units Weighted Average Award Date Fair Value Outstanding at December 31, 2017 269,977 $ 20.14 Awarded 1,900 25.40 Distributed (4,568 ) 22.33 Outstanding at March 31, 2018 267,309 $ 20.14 Expense associated with deferred stock unit awards was less than $0.1 million for each of the quarters ended March 31, 2018 and 2017 . Stock Options Stock options on the Company’s common stock are awarded from time to time to executive officers and certain key employees of the Company. Stock options granted generally have a term of seven to ten years and an exercise price equal to the market value of the underlying common stock on the date of grant. There were 73,897 stock options forfeited during the quarter ended March 31, 2018 with a weighted average exercise price of $26.60 per share. Stock options outstanding and exercisable at March 31, 2018 were 52,783 , with a weighted average exercise price of $18.11 per share. There was no expense associated with stock option grants for both quarters ended March 31, 2018 and 2017 and no unrecognized pre-tax expense related to stock option grants at March 31, 2018 . Financial data for stock option exercises are summarized as follows (in thousands): Quarter Ended 2018 2017 Aggregate intrinsic value of outstanding stock options $ 253 $ 444 Aggregate intrinsic value of exercisable stock options 253 444 The intrinsic value calculations are based on the Company’s closing stock price of $22.91 on both March 31, 2018 and 2017 . The Company uses a binomial option-pricing model for valuation purposes to reflect the features of stock options granted. Volatility, expected term and dividend yield assumptions are based on the Company’s historical experience. The risk-free rate is based on a U.S. treasury note with a maturity similar to the option grant’s expected term. There were no stock options awarded during 2018 or 2017 .

Taxes on Income

Taxes on Income	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Taxes on Income	TAXES ON INCOME The Company’s effective tax rate in the quarter ended March 31, 2018 was a benefit of 40.4% on a pre-tax loss. The benefit was positively impacted by a $1.5 million net tax benefit, or 60.0% benefit to the effective tax rate, related to employee share-based payments vested during the first quarter of 2018. Excluding this benefit, the Company recorded income tax expense on a pre-tax loss primarily due to valuation allowances recorded on certain net operating losses in foreign jurisdictions for which no income tax benefit can be recognized. For the quarter ended March 31, 2017 , the Company’s effective tax rate was 20.5% . The effective rate was favorably impacted by the reversal of previously recorded valuation allowances due to changes in the realization of future tax benefits, primarily in the United States.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Litigation The Company is involved in certain litigation incidental to the conduct of its business and affairs. Management, after consultation with legal counsel, does not believe that the outcome of any such litigation, individually or in the aggregate, will have a material adverse effect on the Company’s consolidated financial condition, results of operations or cash flows. Purchase Commitments The Company had no material purchase commitments at March 31, 2018 . Guarantees The Company has many contracts that require the Company to indemnify the other party against loss from claims, including claims of patent or trademark infringement or other third-party claims for injuries, damages or losses. The Company has agreed to indemnify its surety against losses from third-party claims of subcontractors. The Company has not previously experienced material losses under these provisions and, while there can be no assurances, currently does not anticipate any future material adverse impact on its consolidated financial position, results of operations or cash flows. The Company regularly reviews its exposure under all its engagements, including performance guarantees by contractual joint ventures and indemnification of its surety. As a result of the most recent review, the Company has determined that the risk of material loss is remote under these arrangements and has not recorded a liability for these risks at March 31, 2018 on its Consolidated Balance Sheet.

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Reporting	SEGMENT REPORTING The Company has three operating segments, which are also its reportable segments: Infrastructure Solutions; Corrosion Protection; and Energy Services. The Company’s operating segments correspond to its management organizational structure. Each operating segment has a president who reports to the Company’s chief executive officer, who is also the chief operating decision manager (“CODM”). The operating results and financial information reported by each segment are evaluated separately, regularly reviewed and used by the CODM to evaluate segment performance, allocate resources and determine management incentive compensation. The following disaggregated financial results have been prepared using a management approach that is consistent with the basis and manner with which management internally disaggregates financial information for the purpose of making internal operating decisions. The Company evaluates performance based on stand-alone operating income (loss), which includes acquisition and divestiture expenses, restructuring charges and an allocation of corporate-related expenses. Financial information by segment was as follows (in thousands): Quarters Ended March 31, 2018 2017 Revenues: Infrastructure Solutions $ 134,427 $ 128,868 Corrosion Protection 98,105 123,390 Energy Services 92,329 72,917 Total revenues $ 324,861 $ 325,175 Gross profit: Infrastructure Solutions $ 26,709 $ 31,251 Corrosion Protection 23,576 27,963 Energy Services 11,219 8,198 Total gross profit $ 61,504 $ 67,412 Operating income (loss): Infrastructure Solutions (1) $ (349 ) $ 5,610 Corrosion Protection (2) 822 7,212 Energy Services 2,708 1,311 Total operating income 3,181 14,133 Other income (expense): Interest expense (5,443 ) (4,047 ) Interest income 47 49 Other (262 ) (387 ) Total other expense (5,658 ) (4,385 ) Income (loss) before taxes on income $ (2,477 ) $ 9,748 _______________________ (1) Operating loss in the first quarter of 2018 includes $3.5 million of 2017 Restructuring charges (see Note 4). Operating income in the first quarter of 2017 includes $0.5 million of costs incurred primarily related to the acquisition of Environmental Techniques. (2) Operating income in the first quarter of 2018 includes $1.7 million of 2017 Restructuring charges (see Note 4) and $0.4 million of costs incurred primarily related to the planned divestiture of Bayou. The following table summarizes revenues, gross profit and operating income (loss) by geographic region (in thousands): Quarters Ended March 31, 2018 2017 Revenues (1) : United States $ 250,032 $ 257,724 Canada 28,839 26,827 Europe 16,009 16,145 Other foreign 29,981 24,479 Total revenues $ 324,861 $ 325,175 Gross profit: United States $ 49,562 $ 56,032 Canada 4,775 4,514 Europe 1,134 3,159 Other foreign 6,033 3,707 Total gross profit $ 61,504 $ 67,412 Operating income (loss): United States $ 4,913 $ 12,517 Canada 1,153 1,460 Europe (2,445 ) 408 Other foreign (440 ) (252 ) Total operating income $ 3,181 $ 14,133 __________________________ (1) Revenues 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.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	DERIVATIVE FINANCIAL INSTRUMENTS As a matter of policy, the Company uses derivatives for risk management purposes, and does not use derivatives for speculative purposes. From time to time, the Company may enter into foreign currency forward contracts to hedge foreign currency cash flow transactions. For cash flow hedges, a gain or loss is recorded in the Consolidated Statements of Operations upon settlement of the hedge. All of the Company’s hedges that are designated as hedges for accounting purposes were highly effective; therefore, no notable amounts of hedge ineffectiveness were recorded in the Company’s Consolidated Statements of Operations for either the settlement of cash flow hedges or the outstanding hedged balance. At March 31, 2018 , the Company’s cash flow hedges were in a net deferred gain position of $4.0 million due to favorable movements in short-term interest rates relative to the hedged position. The gain was recorded in prepaid expenses and other current assets and other comprehensive income on the Consolidated Balance Sheets and on the foreign currency translation adjustment and derivative transactions line of the Consolidated Statements of Equity. The Company presents derivative instruments in the consolidated financial statements on a gross basis. The gross and net difference of derivative instruments are considered to be immaterial to the financial position presented in the financial statements. The Company also engages in regular inter-company trade activities and receives royalty payments from certain of its wholly-owned entities, paid in local currency, rather than the Company’s functional currency, U.S. dollars. The Company utilizes foreign currency forward exchange contracts to mitigate the currency risk associated with the anticipated future payments from certain of its international entities. During the first quarters of 2018 and 2017 , a $0.1 million loss was recorded in each period upon settlement of forward exchange contracts. Gains and losses of this nature are recorded to “Other income (expense)” in the Consolidated Statements of Operations. In October 2015, the Company entered into an interest rate swap agreement for a notional amount of $262.5 million , which is set to expire in October 2020. The notional amount of this swap mirrored the amortization of a $262.5 million portion of the Company’s $350.0 million term loan drawn from the original Credit Facility. The swap requires the Company to make a monthly fixed rate payment of 1.46% calculated on the amortizing $262.5 million notional amount and provides for the Company to receive a payment based upon a variable monthly LIBOR interest rate calculated by amortizing the $262.5 million same notional amount. The receipt of the monthly LIBOR-based payment offsets a variable monthly LIBOR-based interest cost on a corresponding $262.5 million portion of the Company’s term loan from the original Credit Facility. This interest rate swap is used to partially hedge the interest rate risk associated with the volatility of monthly LIBOR rate movement and is accounted for as a cash flow hedge. On March 12, 2018, the Company entered into an interest rate swap forward agreement that begins in October 2020 and expires in February 2023 to coincide with the amortization period of the amended Credit Facility. The swap requires the Company to make a monthly fixed rate payment of 2.937% calculated on the then amortizing $170.6 million notional amount, and provides for the Company to receive a payment based upon a variable monthly LIBOR interest rate calculated on the same amortizing $170.6 million notional amount. The receipt of the monthly LIBOR-based payment offsets a variable monthly LIBOR-based interest cost on a corresponding $170.6 million portion of the Company’s term loan from the amended Credit Facility. This interest rate swap is used to partially hedge the interest rate risk associated with the volatility of monthly LIBOR rate movement and is accounted for as a cash flow hedge. The following table summarizes the Company’s derivative positions at March 31, 2018 : Position Notional Amount Weighted Average Remaining Maturity In Years Average Exchange Rate USD/British Pound Sell £ 1,761,800 0.3 1.41 EURO/British Pound Sell £ 2,568,300 0.3 1.14 USD/South African Rand Sell R 5,747,262 0.1 0.08 Interest Rate Swap $ 226,406,250 4.8 The following table provides a summary of the fair value amounts of our derivative instruments, all of which are Level 2 inputs as defined below (in thousands): Designation of Derivatives Balance Sheet Location March 31, 2018 December 31, 2017 Derivatives Designated as Hedging Instruments: Forward Currency Contracts Prepaid expenses and other current assets $ — $ 176 Interest Rate Swaps Other non-current assets 4,885 3,193 Total Assets $ 4,885 $ 3,369 Forward Currency Contracts Accrued expenses $ 7 $ 33 Interest Rate Swaps Other non-current liabilities 871 — Total Liabilities $ 878 $ 33 Derivatives Not Designated as Hedging Instruments: Forward Currency Contracts Prepaid expenses and other current assets $ — $ 10 Total Assets $ — $ 10 Forward Currency Contracts Accrued expenses $ 88 $ — Total Liabilities $ 88 $ — Total Derivative Assets $ 4,885 $ 3,379 Total Derivative Liabilities 966 33 Total Net Derivative Asset (Liability) $ 3,919 $ 3,346 FASB ASC 820, Fair Value Measurements (“FASB ASC 820”), defines fair value and establishes a framework for measuring and disclosing fair value instruments. The guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: • Level 1 – defined as quoted prices in active markets for identical instruments; • Level 2 – defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; • Level 3 – defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. In accordance with FASB ASC 820, the Company determined that the value of all of its derivative instruments, which are measured at fair value on a recurring basis, are derived from significant observable inputs, referred to as Level 2 inputs. The Company had no transfers between Level 1, 2 or 3 inputs during the quarter ended March 31, 2018 . Certain financial instruments are required to be recorded at fair value. Changes in assumptions or estimation methods could affect the fair value estimates; however, the Company does not believe any such changes would have a material impact on its financial condition, results of operations or cash flows. Other financial instruments including cash and cash equivalents and short-term borrowings, including notes payable, are recorded at cost, which approximates fair value, which is based on Level 2 inputs as previously defined.

Accounting Policies (Policies)

Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Foreign Currency Translation	Foreign Currency Translation For the Company’s international subsidiaries, the local currency is generally the functional currency. Assets and liabilities of these subsidiaries are translated into U.S. dollars using rates in effect at the balance sheet date while revenues and expenses are translated into U.S. dollars using average exchange rates. The cumulative translation adjustment resulting from changes in exchange rates are included in the Consolidated Balance Sheets as a component of “Accumulated other comprehensive loss” in total stockholders’ equity.
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents	The Company classifies highly liquid investments with original maturities of 90 days or less as cash equivalents. Recorded book values are reasonable estimates of fair value for cash and cash equivalents.
Investments in Variable Interest Entities	Investments in Variable Interest Entities The Company evaluates all transactions and relationships with variable interest entities (“VIE”) to determine whether the Company is the primary beneficiary of the entities in accordance with FASB ASC 810, Consolidation . There were no changes in the Company’s
Newly Issued Accounting Pronouncements	Newly Issued Accounting Pronouncements In February 2018, the FASB issued Accounting Standards Update No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which permits a company to reclassify the income tax effects of the TCJA on items within accumulated other comprehensive income to retained earnings. The guidance is effective for the Company’s fiscal year beginning January 1, 2019, including interim periods within that fiscal year. Companies may adopt the new guidance using one of two transition methods: (i) retrospective to each period (or periods) in which the income tax effects are recognized, or (ii) at the beginning of the period of adoption. The Company is currently evaluating the effect the guidance will have on its consolidated financial statements. In August 2017, the FASB issued Accounting Standards Update No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities , which amends the recognition and presentation requirements for hedge accounting activities. The standard improves the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements and reduces the complexity of applying hedge accounting. This new guidance is effective for the Company’s fiscal year beginning January 1, 2019, but the Company early-adopted this standard, effective January 1, 2018. The adoption of this standard did not have a material impact on its consolidated financial statements. In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash , which requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. As a result, restricted cash is included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. This new guidance was effective for the Company’s fiscal year beginning January 1, 2018 and applied retrospectively. The Company’s adoption of this standard, effective January 1, 2018, did not have a material impact on its consolidated financial statements, other than the classification of restricted cash on the Consolidated Statement of Cash Flows. In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which addresses diversity in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard was effective for the Company’s fiscal year beginning January 1, 2018, the adoption of which did not have a material impact on its consolidated financial statements. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) , that requires lessees to present right-of-use assets and lease liabilities on the balance sheet for all leases with lease terms longer than twelve months. The standard is effective for the Company’s fiscal year beginning January 1, 2019, including interim periods within that fiscal year. Early adoption is permitted, although the Company does not intend to do so. The Company intends to adopt the new guidance using the cumulative effect method, which would apply to all new lease contracts initiated on or after January 1, 2019. For existing lease contracts that have remaining obligations as of January 1, 2019, the difference between the recognition criteria in the new guidance and the Company’s current practices would be recognized using a cumulative effect adjustment to the opening balance of retained earnings. In early 2017, the Company identified a project manager as well as a cross-functional implementation team responsible for identifying and assessing the impact on its lease contracts. During 2017, the implementation team began the assessment phase, which included data retrieval from the Company’s key third-party lease administration vendors and the identification of the Company’s known lease contracts throughout the world. During the first half of 2018, the Company will: (i) perform an analysis of the new standard on its current lease contracts as well as other existing arrangements to determine if they qualify for lease accounting under the new standard; and (ii) identify potential changes to business processes, systems and controls to support recognition and disclosure under the new standard. In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which replaces revenue recognition requirements regarding contracts with customers to transfer goods or services with a single revenue recognition model for recognizing revenue. Under the new guidance, entities are required to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides a five-step analysis to be performed on transactions to determine when and how revenue is recognized. The Company adopted this standard, effective January 1, 2018, using the modified retrospective transition method. See Note 3.
Segment Reporting	The Company has three operating segments, which are also its reportable segments: Infrastructure Solutions; Corrosion Protection; and Energy Services. The Company’s operating segments correspond to its management organizational structure. Each operating segment has a president who reports to the Company’s chief executive officer, who is also the chief operating decision manager (“CODM”). The operating results and financial information reported by each segment are evaluated separately, regularly reviewed and used by the CODM to evaluate segment performance, allocate resources and determine management incentive compensation. The following disaggregated financial results have been prepared using a management approach that is consistent with the basis and manner with which management internally disaggregates financial information for the purpose of making internal operating decisions. The Company evaluates performance based on stand-alone operating income (loss), which includes acquisition and divestiture expenses, restructuring charges and an allocation of corporate-related expenses.
Derivative Financial Instruments	As a matter of policy, the Company uses derivatives for risk management purposes, and does not use derivatives for speculative purposes. From time to time, the Company may enter into foreign currency forward contracts to hedge foreign currency cash flow transactions. For cash flow hedges, a gain or loss is recorded in the Consolidated Statements of Operations upon settlement of the hedge. All of the Company’s hedges that are designated as hedges for accounting purposes were highly effective; therefore, no notable amounts of hedge ineffectiveness were recorded in the Company’s Consolidated Statements of Operations for either the settlement of cash flow hedges or the outstanding hedged balance.

General (Tables)

General (Tables)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of contribution to revenues and profits and pro forma	Environmental Techniques made the following contributions to the Company’s revenues and profits (in thousands): Quarters Ended March 31, 2018 2017 Revenues $ 2,260 $ 451 Net income (loss) 11 (102 ) The following pro-forma summary presents combined information of the Company as if the Environmental Techniques acquisition had occurred at the beginning of the year preceding its acquisition (in thousands, except earnings per share): Quarter Ended March 31, 2017 Revenues $ 326,057 Net income attributable to Aegion Corporation (1) 5,698 Diluted earnings per share $ 0.17 _____________________ (1) Includes pro-forma adjustments for depreciation and amortization associated with acquired tangible and intangible assets, as if those assets were recorded at the beginning of the year preceding the acquisition date.
Schedule of fair value of assets acquired and liabilities assumed	The following table summarizes the fair value of identified assets and liabilities of Environmental Techniques at its acquisition date (in thousands): Environmental Techniques Receivables and cost and estimated earnings in excess of billings $ 801 Inventories 1,281 Prepaid expenses and other current assets 93 Property, plant and equipment 2,147 Identified intangible assets 1,869 Deferred income tax assets 124 Accounts payable (1,025 ) Accrued expenses (186 ) Deferred income tax liabilities (413 ) Total identifiable net assets $ 4,691 Total consideration recorded $ 8,046 Less: total identifiable net assets 4,691 Final purchase price goodwill $ 3,355

Accounting Policies (Tables)

Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of accumulated other comprehensive income (loss)	The Company’s accumulated other comprehensive loss is comprised of three main components: (i) currency translation; (ii) derivatives; and (iii) gains and losses associated with the Company’s defined benefit plan in the United Kingdom (in thousands): March 31, 2018 December 31, 2017 Currency translation adjustments $ (33,928 ) $ (35,928 ) Derivative hedging activity 4,007 3,336 Pension activity (253 ) (244 ) Total accumulated other comprehensive loss $ (30,174 ) $ (32,836 )
Schedule of weighted average number of shares	Earnings per share have been calculated using the following share information: Quarters Ended March 31, 2018 2017 Weighted average number of common shares used for basic EPS 32,483,963 33,819,331 Effect of dilutive stock options and restricted and deferred stock unit awards — 685,257 Weighted average number of common shares and dilutive potential common stock used in dilutive EPS 32,483,963 34,504,588
Restrictions on cash and cash equivalents	Cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets and Consolidated Statements of Cash Flows are as follows (in thousands): Balance sheet data March 31, December 31, Cash and cash equivalents (1) $ 87,173 $ 105,717 Restricted cash 1,858 1,839 Cash, cash equivalents and restricted cash $ 89,031 $ 107,556 __________________________ (1) Amounts exclude $0.8 million and $1.0 million of cash and cash equivalents classified as held for sale at March 31, 2018 and December 31, 2017, respectively.
Financial data for consolidated variable interest entities	Financial data for consolidated variable interest entities are summarized in the following tables (in thousands): Balance sheet data March 31, (1) December 31, (2) Current assets $ 41,877 $ 42,732 Non-current assets 26,725 26,346 Current liabilities 12,275 12,449 Non-current liabilities 28,371 30,675 __________________________ (1) Amounts include $25.2 million of assets and $9.3 million of liabilities classified as held for sale relating to our pipe coating and insulation joint venture in Louisiana, Bayou Wasco Insulation, LLC. See Note 5. (2) Amounts include $25.4 million of assets and $9.8 million of liabilities classified as held for sale relating to our pipe coating and insulation joint venture in Louisiana, Bayou Wasco Insulation, LLC. See Note 5. Quarters Ended March 31, Income statement data (1) 2018 2017 (1) Revenue $ 16,051 $ 34,061 Gross profit 3,310 5,530 Net income attributable to Aegion Corporation 1,248 1,272 __________________________ (1) During the first quarter of 2017, increased activity was primarily driven from our joint venture in Louisiana, which performed work on a large deepwater pipe coating and insulation project.

Revenues (Tables)

Revenues (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables summarize revenues by segment and geography (in thousands): Quarter Ended March 31, 2018 Infrastructure Solutions Corrosion Protection Energy Services Total Primary geographic region: United States $ 93,845 $ 63,858 $ 92,329 $ 250,032 Canada 12,269 16,570 — 28,839 Europe 13,143 2,866 — 16,009 Other foreign 15,170 14,811 — 29,981 Total revenues $ 134,427 $ 98,105 $ 92,329 $ 324,861 Quarter Ended March 31, 2017 Infrastructure Solutions Corrosion Protection Energy Services Total Primary geographic region: United States $ 93,904 $ 90,903 $ 72,917 $ 257,724 Canada 10,817 16,010 — 26,827 Europe 12,960 3,185 — 16,145 Other foreign 11,187 13,292 — 24,479 Total revenues $ 128,868 $ 123,390 $ 72,917 $ 325,175 The following tables summarize revenues by segment and contract type (in thousands): Quarter Ended March 31, 2018 Infrastructure Solutions Corrosion Protection Energy Services Total Contract type: Fixed fee $ 125,263 $ 77,901 $ 5,757 $ 208,921 Time and materials — 13,107 86,572 99,679 Product sales 9,144 7,097 — 16,241 License fees 20 — — 20 Total revenues $ 134,427 $ 98,105 $ 92,329 $ 324,861 Quarter Ended March 31, 2017 Infrastructure Solutions Corrosion Protection Energy Services Total Contract type: Fixed fee $ 118,998 $ 98,520 $ 1,507 $ 219,025 Time and materials — 11,476 71,410 82,886 Product sales 9,714 13,394 — 23,108 License fees 156 — — 156 Total revenues $ 128,868 $ 123,390 $ 72,917 $ 325,175
Contract Asset and Liability	Net contract assets (liabilities) consisted of the following (in thousands): March 31, 2018 December 31, 2017 Contract assets – current $ 81,052 $ 75,371 Contract assets – noncurrent (1) 11 — Contract liabilities – current (45,139 ) (51,597 ) Net contract assets (liabilities) $ 35,924 $ 23,774 __________________________ (1) Included in “Other assets” on the Consolidated Balance Sheets.

Restructuring (Tables)

Restructuring (Tables)	3 Months Ended
	Mar. 31, 2018
Restructuring and Related Activities [Abstract]
Summary of restructuring and related costs	During the first quarter of 2018, the Company recorded pre-tax expenses related to the 2017 Restructuring as follows (in thousands): Infrastructure Solutions Corrosion Protection Total Severance and benefit related costs $ 865 $ 206 $ 1,071 Lease and contract termination costs 528 150 678 Relocation and other moving costs 40 — 40 Other restructuring costs (1) 2,100 1,355 3,455 Total pre-tax restructuring charges (2) $ 3,533 $ 1,711 $ 5,244 __________________________ (1) Includes charges primarily related to certain wind-down costs, allowances for accounts receivable and other restructuring-related costs in connection with exiting non-pipe-related contract applications for the Tyfo ® system in North America. (2) Includes $0.6 million of corporate-related restructuring charges that have been allocated to the Infrastructure Solutions and Corrosion Protection reportable segments. The following table summarizes all charges related to the 2017 Restructuring recognized in the quarter ended March 31, 2018 as presented in their affected line in the Consolidated Statements of Operations (in thousands): Infrastructure Solutions Corrosion Protection Total (1) Operating expenses $ 2,100 $ 1,355 $ 3,455 Restructuring and related charges 1,433 356 1,789 Total pre-tax restructuring charges $ 3,533 $ 1,711 $ 5,244 __________________________ (1) Total pre-tax restructuring charges include cash charges of $2.8 million and non-cash charges of $2.4 million . Cash charges consist of charges incurred during the quarter that will be settled in cash, either during the current period or future periods.
Summary of restructuring activity	The following table summarizes the 2017 Restructuring activity during the first quarter of 2018 (in thousands): Reserves at December 31, 2017 2018 Foreign Currency Translation Utilized in 2018 Reserves at Cash (1) Non-Cash Severance and benefit related costs $ 3,864 $ 1,071 $ 20 $ 2,305 $ — $ 2,650 Lease and contract termination costs 650 678 — 793 — 535 Relocation and other moving costs — 40 — 40 — — Other restructuring costs 675 3,455 — 1,272 2,408 450 Total pre-tax restructuring charges $ 5,189 $ 5,244 $ 20 $ 4,410 $ 2,408 $ 3,635 __________________________ (1) Refers to cash utilized to settle charges during the first quarter of 2018.

Assets and Liabilities Held f26

Assets and Liabilities Held for Sale (Tables)	3 Months Ended
	Mar. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Schedule of assets and liabilities held for sale	The following table provides the components of assets and liabilities held for sale (in thousands): March 31, December 31, Assets held for sale: Current assets Cash and cash equivalents $ 813 $ 989 Receivables, net 8,143 6,368 Contract assets 1,371 1,299 Inventories 3,541 3,727 Prepaid expenses and other current assets 763 827 Total current assets 14,631 13,210 Property, plant & equipment, less accumulated depreciation 54,835 53,887 Identified intangible assets, less accumulated amortization 3,217 3,217 Total assets held for sale $ 72,683 $ 70,314 Liabilities held for sale: Current liabilities Accounts payable $ 2,249 $ 5,763 Accrued expenses 1,543 1,805 Contract liabilities 3,076 5,478 Total current liabilities 6,868 13,046 Long-term debt 7,757 7,757 Other non-current liabilities 106 97 Total liabilities held for sale $ 14,731 $ 20,900

Goodwill and Identified Intan27

Goodwill and Identified Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of goodwill	The following table presents a reconciliation of the beginning and ending balances of the Company’s goodwill (in thousands): Infrastructure Corrosion Energy Total Balance, December 31, 2017: Goodwill, gross $ 246,486 $ 74,369 $ 80,246 $ 401,101 Accumulated impairment losses (61,459 ) (45,400 ) (33,527 ) (140,386 ) Goodwill, net 185,027 28,969 46,719 260,715 2018 Activity: Foreign currency translation 572 (269 ) — 303 Balance, March 31, 2018: Goodwill, gross 247,058 74,100 80,246 401,404 Accumulated impairment losses (61,459 ) (45,400 ) (33,527 ) (140,386 ) Goodwill, net $ 185,599 $ 28,700 $ 46,719 $ 261,018
Schedule of identified intangible assets	Intangible assets consisted of the following (in thousands): March 31, 2018 December 31, 2017 Weighted Average Useful Lives (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount License agreements 10.8 $ 4,511 $ (3,667 ) $ 844 $ 4,497 $ (3,623 ) $ 874 Leases 2.8 796 (556 ) 240 796 (534 ) 262 Trademarks 10.2 15,494 (6,508 ) 8,986 15,464 (6,184 ) 9,280 Non-competes 2.0 1,201 (1,075 ) 126 1,197 (1,048 ) 149 Customer relationships 9.7 160,543 (59,638 ) 100,905 160,423 (56,907 ) 103,516 Patents and acquired technology 6.0 39,100 (21,380 ) 17,720 39,285 (21,021 ) 18,264 $ 221,645 $ (92,824 ) $ 128,821 $ 221,662 $ (89,317 ) $ 132,345
Schedule of estimated amortization expense	Estimated amortization expense by year is as follows (in thousands): 2018 $ 13,770 2019 13,572 2020 13,518 2021 13,335 2022 13,335

Long-Term Debt and Credit Fac28

Long-Term Debt and Credit Facility (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt consisted of the following (in thousands): March 31, 2018 December 31, 2017 Term note, due February 27, 2023, annualized rates of 3.98% and 3.60%, respectively $ 301,875 $ 308,437 Line of credit, 3.82% and 3.50%, respectively 43,000 38,000 Other notes with interest rates from 3.3% to 7.8% 330 875 Subtotal 345,205 347,312 Less – Current maturities of long-term debt 26,557 26,555 Less – Unamortized loan costs 3,019 2,517 Total $ 315,629 $ 318,240

Stockholders' Equity and Equi29

Stockholders' Equity and Equity Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Summary of all stock award activity	A summary of the stock award activity is as follows: Quarter Ended Stock Awards Weighted Average Award Date Fair Value Outstanding at December 31, 2017 1,428,878 $ 21.53 Restricted stock units awarded 245,886 24.12 Performance stock units awarded 219,943 23.25 Restricted stock units distributed (275,384 ) 17.29 Performance stock units distributed (296,909 ) 21.55 Restricted stock units forfeited (12,207 ) 19.73 Performance stock units forfeited (11,801 ) 25.83 Outstanding at March 31, 2018 1,298,406 $ 23.19
Summary of all deferred stock unit activity	A summary of deferred stock unit activity is as follows: Quarter Ended Deferred Stock Units Weighted Average Award Date Fair Value Outstanding at December 31, 2017 269,977 $ 20.14 Awarded 1,900 25.40 Distributed (4,568 ) 22.33 Outstanding at March 31, 2018 267,309 $ 20.14
Financial data for stock option exercises	Financial data for stock option exercises are summarized as follows (in thousands): Quarter Ended 2018 2017 Aggregate intrinsic value of outstanding stock options $ 253 $ 444 Aggregate intrinsic value of exercisable stock options 253 444

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Financial information by segment	Financial information by segment was as follows (in thousands): Quarters Ended March 31, 2018 2017 Revenues: Infrastructure Solutions $ 134,427 $ 128,868 Corrosion Protection 98,105 123,390 Energy Services 92,329 72,917 Total revenues $ 324,861 $ 325,175 Gross profit: Infrastructure Solutions $ 26,709 $ 31,251 Corrosion Protection 23,576 27,963 Energy Services 11,219 8,198 Total gross profit $ 61,504 $ 67,412 Operating income (loss): Infrastructure Solutions (1) $ (349 ) $ 5,610 Corrosion Protection (2) 822 7,212 Energy Services 2,708 1,311 Total operating income 3,181 14,133 Other income (expense): Interest expense (5,443 ) (4,047 ) Interest income 47 49 Other (262 ) (387 ) Total other expense (5,658 ) (4,385 ) Income (loss) before taxes on income $ (2,477 ) $ 9,748 _______________________ (1) Operating loss in the first quarter of 2018 includes $3.5 million of 2017 Restructuring charges (see Note 4). Operating income in the first quarter of 2017 includes $0.5 million of costs incurred primarily related to the acquisition of Environmental Techniques. (2) Operating income in the first quarter of 2018 includes $1.7 million of 2017 Restructuring charges (see Note 4) and $0.4 million of costs incurred primarily related to the planned divestiture of Bayou.
Summary of revenues, gross profit, and operating income by geographic region	The following table summarizes revenues, gross profit and operating income (loss) by geographic region (in thousands): Quarters Ended March 31, 2018 2017 Revenues (1) : United States $ 250,032 $ 257,724 Canada 28,839 26,827 Europe 16,009 16,145 Other foreign 29,981 24,479 Total revenues $ 324,861 $ 325,175 Gross profit: United States $ 49,562 $ 56,032 Canada 4,775 4,514 Europe 1,134 3,159 Other foreign 6,033 3,707 Total gross profit $ 61,504 $ 67,412 Operating income (loss): United States $ 4,913 $ 12,517 Canada 1,153 1,460 Europe (2,445 ) 408 Other foreign (440 ) (252 ) Total operating income $ 3,181 $ 14,133 __________________________ (1) Revenues 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.

Derivative Financial Instrume31

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of derivative positions	The following table summarizes the Company’s derivative positions at March 31, 2018 : Position Notional Amount Weighted Average Remaining Maturity In Years Average Exchange Rate USD/British Pound Sell £ 1,761,800 0.3 1.41 EURO/British Pound Sell £ 2,568,300 0.3 1.14 USD/South African Rand Sell R 5,747,262 0.1 0.08 Interest Rate Swap $ 226,406,250 4.8
Summary of fair value amounts of derivative instruments	The following table provides a summary of the fair value amounts of our derivative instruments, all of which are Level 2 inputs as defined below (in thousands): Designation of Derivatives Balance Sheet Location March 31, 2018 December 31, 2017 Derivatives Designated as Hedging Instruments: Forward Currency Contracts Prepaid expenses and other current assets $ — $ 176 Interest Rate Swaps Other non-current assets 4,885 3,193 Total Assets $ 4,885 $ 3,369 Forward Currency Contracts Accrued expenses $ 7 $ 33 Interest Rate Swaps Other non-current liabilities 871 — Total Liabilities $ 878 $ 33 Derivatives Not Designated as Hedging Instruments: Forward Currency Contracts Prepaid expenses and other current assets $ — $ 10 Total Assets $ — $ 10 Forward Currency Contracts Accrued expenses $ 88 $ — Total Liabilities $ 88 $ — Total Derivative Assets $ 4,885 $ 3,379 Total Derivative Liabilities 966 33 Total Net Derivative Asset (Liability) $ 3,919 $ 3,346

General - Additional Informatio

General - Additional Information (Details) $ in Thousands, £ in Millions	Mar. 01, 2017GBP (£)	Mar. 01, 2017USD ($)	Sep. 30, 2017
Environmental Techniques
General [Line Items]
Total consideration recorded	£ 6.5	$ 8,000
Aegion South Africa Proprietary Limited
General [Line Items]
Ownership percentage by parent			60.00%
Ownership percentage by noncontrolling owners			40.00%

Accounting Policies - Foreign C

Accounting Policies - Foreign Currency (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accounting Policies [Abstract]
Currency translation adjustments	$ (33,928)		$ (35,928)
Derivative hedging activity	4,007		3,336
Pension activity	(253)		(244)
Total accumulated other comprehensive loss	(30,174)		$ (32,836)
Loss on foreign currency transactions	$ 315	$ 378

General - Contributions to Reve

General - Contributions to Revenues and Profits Since Acquisitions (Details) - Environmental Techniques - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Business Acquisition [Line Items]
Revenues	$ 2,260	$ 451
Net income (loss)	$ (11)	$ 102

Accounting Policies - Taxation

Accounting Policies - Taxation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Accounting Policies [Abstract]
Income tax expense	$ 5.1
Valuation allowance	(5.1)
Provisional income tax expense (benefit)	2.4
Transition tax for accumulated foreign earnings, provisional income tax expense	10.4
Change in tax rate	7.1
Other provisional income tax expense (benefit)	$ 0.9

General - Pro Forma Information

General - Pro Forma Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)$ / shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenues	$ 326,057
Net income attributable to Aegion Corporation	$ 5,698
Diluted earnings per share (in USD per share) | $ / shares	$ 0.17

Accounting Policies - Earnings

Accounting Policies - Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of common shares used for basic EPS (in shares)	32,483,963	33,819,331
Effect of dilutive stock options and restricted and deferred stock unit awards (in shares)	0	685,257
Weighted average number of common shares and dilutive potential common stock used in dilutive EPS (in shares)	32,483,963	34,504,588
Antidilutive securities excluded from calculation of earnings per share (in shares)		77,807
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of earnings per share (in shares)	710,173
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of earnings per share (in shares)	714,741
Deferred Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from calculation of earnings per share (in shares)	714,741

General - Fair Value of Identif

General - Fair Value of Identified Assets and Liabilities (Details) $ in Thousands, £ in Millions	Mar. 01, 2017GBP (£)	Mar. 01, 2017USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Goodwill			$ 261,018	$ 260,715
Environmental Techniques
Business Acquisition [Line Items]
Receivables and cost and estimated earnings in excess of billings		$ 801
Inventories		1,281
Prepaid expenses and other current assets		93
Property, plant and equipment		2,147
Identified intangible assets		1,869
Deferred income tax assets		124
Accounts payable		(1,025)
Accrued expenses		(186)
Deferred income tax liabilities		(413)
Total identifiable net assets		4,691
Total consideration recorded	£ 6.5	8,000
Less: total identifiable net assets		4,691
Goodwill		$ 3,355

Accounting Policies - Cash, Cas

Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounting Policies [Abstract]
Cash and cash equivalents	$ 87,173	$ 105,717
Restricted cash	1,858	1,839
Cash, cash equivalents and restricted cash	89,031	107,556
Held for sale, cash and cash equivalents	$ 813	$ 1,000	$ 0

Accounting Policies - VIE Balan

Accounting Policies - VIE Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Current assets (VIE)	$ 41,877	$ 42,732
Non-current assets (VIE)	26,725	26,346
Current liabilities (VIE)	12,275	12,449
Non-current liabilities (VIE)	28,371	30,675
Bayou Perma-Pipe Canada, Ltd | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Variable Interest Entity [Line Items]
Disposal group, assets	25,200	25,400
Disposal group, liabilities	$ 9,300	$ 9,800

Accounting Policies - VIE Incom

Accounting Policies - VIE Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Revenue	$ 16,051	$ 34,061
Gross profit	3,310	5,530
Net income attributable to Aegion Corporation	$ 1,248	$ 1,272

Revenues - Additional Informati

Revenues - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ 268
Contract with customer, liability, current	$ 45,139			51,597	$ 62,700
Difference Between Work Performed On Open Contracts And Contractual Billing Terms
Disaggregation of Revenue [Line Items]
Changes in contract assets (liabilities)	(5,700)
Difference Related To Customer Advances On Certain Contract
Disaggregation of Revenue [Line Items]
Changes in contract assets (liabilities)	$ 6,500
Products and Services
Disaggregation of Revenue [Line Items]
Revenue recognized, percent	95.00%	92.90%
Product
Disaggregation of Revenue [Line Items]
Revenue recognized, percent	5.00%	7.10%
Retained Earnings
Disaggregation of Revenue [Line Items]
Cumulative effect of new accounting principle in period of adoption				$ 268
Accounting Standards Update 2014-09 | Retained Earnings
Disaggregation of Revenue [Line Items]
Cumulative effect of new accounting principle in period of adoption			$ 300
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Changes in revenues	$ (100)

Revenues - Performance Obligati

Revenues - Performance Obligation (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation	$ 720.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation	$ 711.1
Revenue, remaining performance obligation, percent	98.70%
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 years

Revenues - Disaggreation of Rev

Revenues - Disaggreation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 324,861	$ 325,175
Fixed fee
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	208,921	219,025
Time and materials
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	99,679	82,886
Product sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	16,241	23,108
License fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	20	156
United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	250,032	257,724
Canada
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	28,839	26,827
Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	16,009	16,145
Other foreign
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	29,981	24,479
Infrastructure Solutions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	134,427	128,868
Infrastructure Solutions | Fixed fee
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	125,263	118,998
Infrastructure Solutions | Time and materials
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Infrastructure Solutions | Product sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	9,144	9,714
Infrastructure Solutions | License fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	20	156
Infrastructure Solutions | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	93,845	93,904
Infrastructure Solutions | Canada
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	12,269	10,817
Infrastructure Solutions | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	13,143	12,960
Infrastructure Solutions | Other foreign
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	15,170	11,187
Corrosion Protection
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	98,105	123,390
Corrosion Protection | Fixed fee
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	77,901	98,520
Corrosion Protection | Time and materials
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	13,107	11,476
Corrosion Protection | Product sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	7,097	13,394
Corrosion Protection | License fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Corrosion Protection | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	63,858	90,903
Corrosion Protection | Canada
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	16,570	16,010
Corrosion Protection | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2,866	3,185
Corrosion Protection | Other foreign
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	14,811	13,292
Energy Services
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	92,329	72,917
Energy Services | Fixed fee
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	5,757	1,507
Energy Services | Time and materials
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	86,572	71,410
Energy Services | Product sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Energy Services | License fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Energy Services | United States
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	92,329	72,917
Energy Services | Canada
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Energy Services | Europe
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Energy Services | Other foreign
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 0	$ 0

Revenues - Contract Assets (Lia

Revenues - Contract Assets (Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from Contract with Customer [Abstract]
Contract assets – current	$ 81,052	$ 75,371
Contract assets – noncurrent	11	0
Contract liabilities – current	(45,139)	(51,597)	$ (62,700)
Net contract assets (liabilities)	$ 35,924	$ 23,774

Restructuring - Additional Info

Restructuring - Additional Information (Details) $ in Thousands	3 Months Ended		8 Months Ended
	Mar. 31, 2018USD ($)employee	Mar. 31, 2017USD ($)	Mar. 31, 2018USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	$ 1,789	$ 0
Restructuring 2,017
Restructuring Cost and Reserve [Line Items]
Restructuring charges, pre tax	5,200		$ 29,000
Restructuring charges, net of tax	4,700		25,300
Restructuring reserve, settled without cash	2,408		12,500
Payments for restructuring	$ 4,410		16,500
Headcount reduction | employee	310
Restructuring and related charges	$ 5,244
Restructuring charges excluding other | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	1,800
Minimum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges	2,000		2,000
Maximum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges	$ 5,000		$ 5,000

Restructuring - Pre Tax Restruc

Restructuring - Pre Tax Restructuring Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,789	$ 0
Restructuring 2,017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	5,244
Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,071
Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	678
Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	40
Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,455
Infrastructure Solutions | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3,533
Infrastructure Solutions | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	865
Infrastructure Solutions | Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	528
Infrastructure Solutions | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	40
Infrastructure Solutions | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2,100
Corrosion Protection | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,711
Corrosion Protection | Severance and benefit related costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	206
Corrosion Protection | Lease and contract termination costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	150
Corrosion Protection | Relocation and other moving costs | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0
Corrosion Protection | Other restructuring | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,355
Corporate, Non-Segment | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 600

Restructuring - Recognized Cost

Restructuring - Recognized Cost Restructuring Activities (Details) - Restructuring 2017 $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	$ 5,244
Restructuring charges, cash	2,800
Restructuring charges, non-cash	2,400
Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	3,455
Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,789
Infrastructure Solutions
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	3,533
Infrastructure Solutions | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	2,100
Infrastructure Solutions | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,433
Corrosion Protection
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,711
Corrosion Protection | Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	1,355
Corrosion Protection | Restructuring and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	$ 356

Restructuring - Restructuring A

Restructuring - Restructuring Activities (Details) - Restructuring 2017 - USD ($) $ in Thousands	3 Months Ended	8 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Restructuring reserve, start	$ 5,189
Restructuring and related cost, incurred cost	5,244
Restructuring reserve, foreign currency translation gain (loss)	20
Payments for restructuring	4,410	$ 16,500
Restructuring reserve, settled without cash	2,408	12,500
Restructuring reserve, end	3,635	3,635
Severance and benefit related costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, start	3,864
Restructuring and related cost, incurred cost	1,071
Restructuring reserve, foreign currency translation gain (loss)	20
Payments for restructuring	2,305
Restructuring reserve, settled without cash	0
Restructuring reserve, end	2,650	2,650
Lease and contract termination costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, start	650
Restructuring and related cost, incurred cost	678
Restructuring reserve, foreign currency translation gain (loss)	0
Payments for restructuring	793
Restructuring reserve, settled without cash	0
Restructuring reserve, end	535	535
Relocation and other moving costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, start	0
Restructuring and related cost, incurred cost	40
Restructuring reserve, foreign currency translation gain (loss)	0
Payments for restructuring	40
Restructuring reserve, settled without cash	0
Restructuring reserve, end	0	0
Other restructuring costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, start	675
Restructuring and related cost, incurred cost	3,455
Restructuring reserve, foreign currency translation gain (loss)	0
Payments for restructuring	1,272
Restructuring reserve, settled without cash	2,408
Restructuring reserve, end	$ 450	$ 450

Assets and Liabilities Held f50

Assets and Liabilities Held for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Assets held for sale:
Cash and cash equivalents	$ 813	$ 1,000	$ 0
Total current assets	72,683	70,314
Liabilities held for sale:
Total current liabilities	14,731	20,900
Bayou | Disposal Group, Held-for-sale, Not Discontinued Operations
Assets held for sale:
Cash and cash equivalents	813	989
Receivables, net	8,143	6,368
Contract assets	1,371	1,299
Inventories	3,541	3,727
Prepaid expenses and other current assets	763	827
Total current assets	14,631	13,210
Property, plant & equipment, less accumulated depreciation	54,835	53,887
Identified intangible assets, less accumulated amortization	3,217	3,217
Total assets held for sale	72,683	70,314
Liabilities held for sale:
Accounts payable	2,249	5,763
Accrued expenses	1,543	1,805
Contract liabilities	3,076	5,478
Total current liabilities	6,868	13,046
Long-term debt	7,757	7,757
Other non-current liabilities	106	97
Total liabilities held for sale	$ 14,731	$ 20,900

Goodwill and Identified Intan51

Goodwill and Identified Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, gross	$ 401,404	$ 401,101
Accumulated impairment losses	(140,386)	(140,386)
Goodwill, beginning balance	260,715
Foreign currency translation	303
Goodwill, ending balance	261,018
Infrastructure Solutions
Goodwill [Roll Forward]
Goodwill, gross	247,058	246,486
Accumulated impairment losses	(61,459)	(61,459)
Goodwill, beginning balance	185,027
Foreign currency translation	572
Goodwill, ending balance	185,599
Corrosion Protection
Goodwill [Roll Forward]
Goodwill, gross	74,100	74,369
Accumulated impairment losses	(45,400)	(45,400)
Goodwill, beginning balance	28,969
Foreign currency translation	(269)
Goodwill, ending balance	28,700
Energy Services
Goodwill [Roll Forward]
Goodwill, gross	80,246	80,246
Accumulated impairment losses	(33,527)	$ (33,527)
Goodwill, beginning balance	46,719
Foreign currency translation	0
Goodwill, ending balance	$ 46,719

Goodwill and Identified Intan52

Goodwill and Identified Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 221,645	$ 221,662
Accumulated Amortization	(92,824)	(89,317)
Net Carrying Amount	$ 128,821	132,345
License agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	10 years 9 months 28 days
Gross Carrying Amount	$ 4,511	4,497
Accumulated Amortization	(3,667)	(3,623)
Net Carrying Amount	$ 844	874
Leases
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	2 years 9 months
Gross Carrying Amount	$ 796	796
Accumulated Amortization	(556)	(534)
Net Carrying Amount	$ 240	262
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	10 years 2 months 5 days
Gross Carrying Amount	$ 15,494	15,464
Accumulated Amortization	(6,508)	(6,184)
Net Carrying Amount	$ 8,986	9,280
Non-competes
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	1 year 11 months 18 days
Gross Carrying Amount	$ 1,201	1,197
Accumulated Amortization	(1,075)	(1,048)
Net Carrying Amount	$ 126	149
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	9 years 8 months
Gross Carrying Amount	$ 160,543	160,423
Accumulated Amortization	(59,638)	(56,907)
Net Carrying Amount	$ 100,905	103,516
Patents and acquired technology
Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Lives (Years)	5 years 11 months 13 days
Gross Carrying Amount	$ 39,100	39,285
Accumulated Amortization	(21,380)	(21,021)
Net Carrying Amount	$ 17,720	$ 18,264

Goodwill and Identified Intan53

Goodwill and Identified Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 3.5	$ 4.3

Goodwill and Identified Intan54

Goodwill and Identified Intangible Assets - Estimated Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 13,770
2,019	13,572
2,020	13,518
2,021	13,335
2,022	$ 13,335

Long-Term Debt and Credit Fac55

Long-Term Debt and Credit Facility - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Subtotal	$ 345,205	$ 347,312
Less – Current maturities of long-term debt	26,557	26,555
Less – Unamortized loan costs	3,019	2,517
Total	315,629	318,240
Term Note
Debt Instrument [Line Items]
Term note, due February 27, 2023, annualized rates of 3.98% and 3.60%, respectively	$ 301,875	$ 308,437
Current effective interest rate	3.98%	3.60%
Line of Credit
Debt Instrument [Line Items]
Line of credit, 3.82% and 3.50%, respectively	$ 43,000	$ 38,000
Current effective interest rate	3.82%	3.50%
Other notes
Debt Instrument [Line Items]
Other notes with interest rates from 3.3% to 7.8%	$ 330	$ 875
Other notes | Minimum
Debt Instrument [Line Items]
Current annualized interest rate	3.30%	3.30%
Other notes | Maximum
Debt Instrument [Line Items]
Current annualized interest rate	7.80%	7.80%

Long-Term Debt and Credit Fac56

Long-Term Debt and Credit Facility - Additional Information (Details)	Feb. 27, 2018	Mar. 31, 2018USD ($)	Mar. 12, 2018USD ($)	Dec. 31, 2017USD ($)	Oct. 31, 2017USD ($)	Oct. 31, 2015USD ($)
Debt Instrument [Line Items]
Fees		$ 2,400,000
Up front lending fees		900,000
Third party arrangement fees		1,500,000
Third-party notes and bank debt held		300,000		$ 900,000
Debt designated as third-party debt		7,800,000		7,700,000
Long-term debt, fair value		344,600,000		356,000,000
2015 Interest Rate Swap
Debt Instrument [Line Items]
Interest rate at period end						3.69%
Notional amount						$ 262,500,000
Fixed interest rate						1.46%
2018 Interest Rate Swap
Debt Instrument [Line Items]
Notional amount			$ 170,600,000
Portion of amortization of term loan			$ 170,600,000
Fixed interest rate			2.937%
Term Loan [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		308,400,000
2015 Credit Facility
Debt Instrument [Line Items]
Senior secured credit facility						$ 650,000,000
Maximum borrowing capacity					$ 350,000,000
Secured debt outstanding		301,900,000		308,400,000
Proceeds from line of credit, net		43,000,000
Letters of credit issued and outstanding		$ 31,100,000
Line of credit				$ 38,000,000
Portion of amortization of term loan						$ 262,500,000
Initial maximum financial leverage ratio		3.75
Actual financial leverage ratio		3.15
Remaining borrowing capacity		$ 68,200,000
Minimum permitted fixed charge coverage ratio		1.15
Actual fixed charge coverage ratio		1.44
2015 Credit Facility | Insurance Carriers Collateral
Debt Instrument [Line Items]
Letters of credit issued and outstanding		$ 13,400,000
2015 Credit Facility | Work Performance Obligations
Debt Instrument [Line Items]
Letters of credit issued and outstanding		$ 17,700,000
2015 Credit Facility | LIBOR | 2015 Interest Rate Swap
Debt Instrument [Line Items]
Interest rate at period end		3.96%
2015 Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate		1.25%
2015 Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate		2.25%
2015 Credit Facility | Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Term		5 years
2015 Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 300,000,000
Term of revolving line of credit	5 years
Maximum borrowing capacity, post sale		275,000,000
Unamortized loan costs		2,400,000
Interest expense, debt		200,000
Proceeds from line of credit, net		$ 5,000,000
Line of Credit
Debt Instrument [Line Items]
Interest rate at period end		3.82%		3.50%
Line of credit		$ 43,000,000		$ 38,000,000
2018 Credit Facility
Debt Instrument [Line Items]
Notional amount			$ 170,600,000

Stockholders' Equity and Equi57

Stockholders' Equity and Equity Compensation - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Oct. 31, 2017
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Share repurchase program, authorized amount	$ 30,000,000		$ 40,000,000
Options forfeited (in shares)	73,897
Options forfeited (in dollars per share)	$ 26.60
Options outstanding (in shares)	52,783
Weighted average exercise price (in dollars per share)	$ 18.11
Closing stock price (in dollars per share)	$ 22.91	$ 22.91
Stock options awarded during period (in shares)		0
Stock Awards
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Share based compensation expense	$ 2,100,000	$ 3,000,000
Unrecognized share based compensation expense	18,100,000
Weighted average recognition period		2 years 2 months 23 days
Deferred Stock Units
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Share based compensation expense	100,000	$ 100,000
Stock Options
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Share based compensation expense	0	$ 0
Unrecognized pre-tax expense related to stock option grants	$ 0
Stock Options | Minimum
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Award vesting period	7 years
Stock Options | Maximum
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Award vesting period	10 years
2016 Employee Plan
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Number of shares available for issuance (in shares)	796,023
2016 Director Plan
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Number of shares available for issuance (in shares)	115,361
Equity Compensation Programs
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Share repurchase program, authorized amount	$ 10,000,000
Stock repurchased during period (in shares)	217,749	95,403
Stock repurchased during period, value	$ 5,300,000	$ 2,100,000
Shares repurchased, average price per share (in dollars per share)	$ 24.14	$ 22.37
Open Market Repurchase Program
Stockholders' Equity and Equity Compensation (Details) [Line Items]
Stock repurchased during period (in shares)	353,831	366,914
Stock repurchased during period, value	$ 8,400,000	$ 8,400,000
Shares repurchased, average price per share (in dollars per share)	$ 23.78	$ 22.82

Stockholders' Equity and Equi58

Stockholders' Equity and Equity Compensation - Summary of Stock Award Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Stock Awards
Outstanding, beginning balance (in shares)	1,428,878
Outstanding, ending balance (in shares)	1,298,406
Weighted Average Award Date Fair Value
Outstanding, beginning balance (in dollars per share)	$ 21.53
Outstanding, ending balance (in dollars per share)	$ 23.19
Restricted Stock Units
Stock Awards
Awarded (in shares)		245,886
Distributed (in shares)		(275,384)
Forfeited (in shares)		(12,207)
Weighted Average Award Date Fair Value
Awarded (in dollars per share)		$ 24.12
Distributed (in dollars per share)		17.29
Forfeited (in dollars per share)		$ 19.73
Performance Units
Stock Awards
Awarded (in shares)		219,943
Distributed (in shares)		(296,909)
Forfeited (in shares)		(11,801)
Weighted Average Award Date Fair Value
Awarded (in dollars per share)		$ 23.25
Distributed (in dollars per share)		21.55
Forfeited (in dollars per share)		$ 25.83

Stockholders' Equity and Equi59

Stockholders' Equity and Equity Compensation - Summary of Deferred Stock Unit Activity (Details)	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Deferred Stock Units
Outstanding, beginning balance (in shares) | shares	1,428,878
Outstanding, ending balance (in shares) | shares	1,298,406
Weighted Average Award Date Fair Value
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 21.53
Outstanding, ending balance (in dollars per share) | $ / shares	$ 23.19
Deferred Stock Units
Deferred Stock Units
Outstanding, beginning balance (in shares) | shares	269,977
Awarded (in shares) | shares	1,900
Distributed (in shares) | shares	(4,568)
Outstanding, ending balance (in shares) | shares	267,309
Weighted Average Award Date Fair Value
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 20.14
Awarded (in dollars per share) | $ / shares	25.40
Distributed (in dollars per share) | $ / shares	22.33
Outstanding, ending balance (in dollars per share) | $ / shares	$ 20.14

Stockholders' Equity and Equi60

Stockholders' Equity and Equity Compensation - Financial Data for Stock Option Exercises (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Aggregate intrinsic value of outstanding stock options	$ 253	$ 444
Aggregate intrinsic value of exercisable stock options	$ 253	$ 444

Taxes on Income (Details)

Taxes on Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Effective income tax expense (benefit) rate	(40.40%)	20.50%
Employee share-based payments, amount	$ 1.5
Employee share-based payments, percentage	(60.00%)

Segment Reporting - Additional

Segment Reporting - Additional Information (Details)	3 Months Ended
	Mar. 31, 2018segment
Segment Reporting [Abstract]
Number of operating segments	3
Number of reportable segments	3

Segment Reporting - Financial I

Segment Reporting - Financial Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 324,861	$ 325,175
Gross profit	61,504	67,412
Operating income (loss)	3,181	14,133
Interest expense	(5,443)	(4,047)
Interest income	47	49
Other	(262)	(387)
Total other expense	(5,658)	(4,385)
Income (loss) before taxes on income	(2,477)	9,748
Restructuring and related charges	1,789	0
Infrastructure Solutions
Segment Reporting Information [Line Items]
Revenues	134,427	128,868
Gross profit	26,709	31,251
Operating income (loss)	(349)	5,610
Acquisition-related expenses		500
Infrastructure Solutions | Restructuring 2017
Segment Reporting Information [Line Items]
Restructuring and related charges	3,500
Corrosion Protection
Segment Reporting Information [Line Items]
Revenues	98,105	123,390
Gross profit	23,576	27,963
Operating income (loss)	822	7,212
Corrosion Protection | Restructuring 2017
Segment Reporting Information [Line Items]
Restructuring and related charges	1,700	2,200
Energy Services
Segment Reporting Information [Line Items]
Revenues	92,329	72,917
Gross profit	11,219	8,198
Operating income (loss)	2,708	1,311
Bayou | Corrosion Protection
Segment Reporting Information [Line Items]
Restructuring costs	$ 400	$ 1,900

Segment Reporting - Summary of

Segment Reporting - Summary of Revenues, Gross Profit and Operating Income (Loss) by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 324,861	$ 325,175
Gross profit	61,504	67,412
Operating income (loss)	3,181	14,133
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	250,032	257,724
Gross profit	49,562	56,032
Operating income (loss)	4,913	12,517
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	28,839	26,827
Gross profit	4,775	4,514
Operating income (loss)	1,153	1,460
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	16,009	16,145
Gross profit	1,134	3,159
Operating income (loss)	(2,445)	408
Other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	29,981	24,479
Gross profit	6,033	3,707
Operating income (loss)	$ (440)	$ (252)

Derivative Financial Instrume65

Derivative Financial Instruments - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 12, 2018	Oct. 31, 2017	Oct. 31, 2015
Debt Instrument [Line Items]
Gain upon settlement of cash flow hedges, (less than $0.1 million)	$ (100,000)	$ 100,000
2015 Credit Facility
Debt Instrument [Line Items]
Amount of hedged item					$ 262,500,000
Maximum borrowing capacity				$ 350,000,000
2018 Credit Facility
Debt Instrument [Line Items]
Notional amount			$ 170,600,000
2015 Interest Rate Swap
Debt Instrument [Line Items]
Notional amount					$ 262,500,000
Fixed interest rate					1.46%
2018 Interest Rate Swap
Debt Instrument [Line Items]
Notional amount			170,600,000
Amount of hedged item			$ 170,600,000
Fixed interest rate			2.937%
Recurring | Designated as Hedging Instrument
Debt Instrument [Line Items]
Net derivative asset	$ 4,000,000

Derivative Financial Instrume66

Derivative Financial Instruments - Summary of Derivative Positions (Details) - 3 months ended Mar. 31, 2018	GBP (£)€ / £$ / £R / $	USD ($)€ / £$ / £R / $	ZAR (R)€ / £$ / £R / $
USD/British Pound | Sell
Derivative [Line Items]
Notional Amount	£ 1,761,800
Weighted Average Remaining Maturity In Years	3 months
Average Exchange Rate | $ / £	1.41	1.41	1.41
EURO/British Pound | Sell
Derivative [Line Items]
Notional Amount	£ 2,568,300
Weighted Average Remaining Maturity In Years	3 months
Average Exchange Rate | € / £	1.14	1.14	1.14
ZAR/USD | Sell
Derivative [Line Items]
Notional Amount | R			R 5,747,262
Weighted Average Remaining Maturity In Years	1 month 10 days
Average Exchange Rate | R / $	0.08	0.08	0.08
Interest Rate Swaps
Derivative [Line Items]
Notional Amount | $		$ 226,406,250
Weighted Average Remaining Maturity In Years	4 years 9 months

Derivative Financial Instrume67

Derivative Financial Instruments - Summary of the Fair Value Amounts of Derivative Instruments (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Significant Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative assets	$ 4,885	$ 3,379
Derivative liabilities	966	33
Net derivative asset (liability)	3,919	3,346
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Net derivative asset (liability)	4,000
Designated as Hedging Instrument | Significant Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative assets	4,885	3,369
Derivative liabilities	878	33
Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Forward Currency Contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	176
Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Forward Currency Contracts | Accrued expenses
Derivatives, Fair Value [Line Items]
Derivative liabilities	7	33
Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Interest Rate Swaps | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative assets	4,885	3,193
Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Interest Rate Swaps | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	871	0
Not Designated as Hedging Instrument | Significant Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative assets	0	10
Derivative liabilities	88	0
Not Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Forward Currency Contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	10
Not Designated as Hedging Instrument | Significant Observable Inputs (Level 2) | Forward Currency Contracts | Accrued expenses
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 88	$ 0