Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings and Government Investigations The Company is subject to periodic lawsuits, investigations and claims that arise in the ordinary course of business. The Company cannot predict with certainty the ultimate resolution of lawsuits, investigations and claims asserted against it. Except possible liabilities that could arise for certain of the matters described below, the Company does not believe that any currently pending legal proceeding to which the Company is a party will have a material adverse effect on its business, results of operations, cash flows or financial condition. The costs of defense and amounts that may be recovered against the Company may be covered by insurance for certain matters. Litigation and Commercial Claims The Company was contracted to perform inspections of welds on various pipeline projects in Texas for a customer. As of September 30, 2020, approximately $1.4 million of past due receivables were outstanding from this customer. The customer provided the Company with notice in December 2019, alleging that the Company’s inspection of 66 welds (out of over 16,000 welds inspected) were not in compliance with the contract, claimed approximately $7.6 million in damages, and requested that the Company pay these damages and any other damages incurred. The Company has filed a lawsuit in the District Court of Bexar County, Texas, 37th Judicial District, in an action captioned Mistras Group, Inc. v. Epic Y-Grade Pipeline LP, to recover the $1.4 million and other amounts due to the Company. The customer filed a counterclaim, alleging breach of contract and seeking recovery of its alleged damages. The Company believes that any successful claim by the customer regarding the Company’s workmanship will be covered by insurance, subject to payment of a deductible. At this time, the Company is unable to determine whether it has any liability in connection with this matter and if so, the amount or range of any such liability, and accordingly, has not established any accruals for this matter. The Company recorded a full reserve in the amount of $1.4 million during the second half of 2019 for these past due receivables. See Note 6–Accounts Receivable, net. Pension Related Contingencies The workforce of certain of the Company’s subsidiaries are unionized and the terms of employment for these workers are governed by collective bargaining agreements, or CBAs. Under these CBAs, the Company’s subsidiaries are required to contribute to the national pension funds for the unions representing these employees, which are multi-employer pension plans. The Company was notified that a significant project was awarded to another contractor in January 2018, and as a result, one of the Company’s subsidiaries experienced a significant reduction in the number of its employees covered by one of the CBAs. Under certain circumstances, such a reduction in the number of employees participating in multi-employer pension plans pursuant to this CBA could result in a complete or partial withdrawal liability to these multi-employer pension plans under the Employee Retirement Income Security Act of 1974 ("ERISA"). Management explored options to retain a level of union work that would avoid withdrawal liability to the pension plans but concluded during the third quarter of 2018 that the Company's subsidiaries probably would not obtain sufficient union work to avoid withdrawal liability. Therefore, the Company determined that it is probable that its subsidiary would incur a withdrawal liability related to these multi-employer pension plans. Accordingly, the Company recorded a charge of $5.9 million during 2018 and $0.8 million during 2019 for this potential withdrawal liability. The Company’s subsidiary reached an agreement with one of the pension funds in September 2019 and made a final payment of $0.9 million in complete satisfaction of the withdrawal liability of the subsidiary. Excluding the settlement payment, the Company made monthly payments totaling $3.3 million through the time of the final settlement payment, for total payments of $4.2 million. The balance of the estimated total amount of this potential liability as of September 30, 2020 is approximately $2.5 million. Severance and labor disputes The Company’s German subsidiary provides employees to customers under temporary staff leasing arrangements. In April 2017, the German Labor Lease Act was passed in Germany limiting the duration of temporary workers to eighteen months, or longer as subsequently agreed with by a customer appropriate authority. Since the passing of the German Labor Lease Act, the Company explored selling its staff leasing services and concluded during the third quarter of 2018 that a sale would not be probable. As a result, the Company decided that it would not renew several of these leasing services contracts when they expired beginning in 2019. Due to the limit on the length of service allowed under the German Labor Lease Act, employees are being transitioned off the customer contracts. The German subsidiary has terminated, or will terminate, some these employees, creating a severance obligation to the terminated employees, and has transitioned, or will transition other employees to the Company's other customers. During December 2019, the Company executed an agreement to sell the rights of certain customer contracts for total consideration of approximately $0.1 million, effective January 1, 2020. No other assets or liabilities other than those employee benefits related to employees working on the customer contracts were included in the sale. As of September 30, 2020, the Company has approximately $0.3 million of accrued estimated severance payment obligations, which takes into account the Company's estimate with respect to the employees that have been or will be transitioned to the German subsidiaries' other customers. The $0.3 million of estimated obligations is net of $0.4 million in payments made and $0.9 million in reversals due to employees being transitioned to customer contracts. Acquisition and disposition related contingencies The Company is liable for contingent consideration in connection with certain of its acquisitions. As of September 30, 2020, total potential acquisition-related contingent consideration ranged from zero to approximately $4.3 million and would be payable upon the achievement of specific performance metrics by certain of the acquired companies over the next 2.0 years. During 2018, the Company sold a subsidiary in the Products and Systems segment. As part of the sale, the Company entered into a three-year agreement to purchase products from the buyer, with a cumulative commitment of $2.3 million, of which $1.3 million is remaining as of September 30, 2020. The agreement is based on third-party pricing and the Company's planned purchase requirements over the three-year purchase period to meet the minimum contractual purchases.