Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings and Government Investigations The Company is periodically involved in lawsuits, investigations and claims. While uncertainties exist with respect to the ultimate resolution of lawsuits, investigations and claims asserted against it, except as stated below, the Company, based on currently available information, does not believe that any currently pending or threatened legal proceeding to which the Company is a party, or is likely to become a party, will have a material adverse effect on its business, results of operations, cash flows or financial condition. The costs incurred by the Company to defend lawsuits, investigations and claims and amounts the Company pays to other parties because of these matters may be covered by insurance in some circumstances. Litigation and Commercial Claims The Company and a subsidiary of the Company, Mistras Arizona Inspection Services LLC (“Mistras Arizona”), are subject to a lawsuit ("the DEQ Proceeding") filed by the State of Arizona and the Arizona Department of Environmental Quality (collectively “DEQ”). The DEQ Proceeding, captioned State of Arizona v. Mistras Group, Inc., Mistras Arizona Inspection Services, LLC and Naiman Phoenix, Ltd., was originally filed on February 27, 2024, in the Superior Court of the State of Arizona for Maricopa County, CV 2024-003866 (the "DEQ Complaint"). The DEQ Complaint alleges various violations of Arizona environmental laws and regulations by Mistras Arizona in connection with the operation by Mistras Arizona of its testing facility in Phoenix, Arizona. The DEQ Complaint seeks, through injunctive relief, the closing of a chromic acid plating line at the testing facility, implementation of a site assessment plan approved by the DEQ, and corrective and remedial action to bring the testing facility into compliance with laws and regulations. In addition, the DEQ is seeking unspecified penalties and costs in connection with the DEQ Proceeding. The Superior Court held a hearing in September 2024 regarding the DEQ’s request for a preliminary injunction. On October 23, 2024, the Superior Court issued a ruling, which declined to issue the preliminary injunction requested by the DEQ, but imposed the following conditions on the Company and Mistras Arizona unless and until modified by the Superior Court or entry of a final judgment: (1) the Company and Mistras Arizona are prohibited from releasing or permitting any release of chromic acid from the facility; (2) within a reasonable time, the Company and Mistras Arizona must complete improvements to the testing facility designed to prevent future discharges of chromium or chromic acid; (3) the Company and Mistras Arizona must notify the DEQ upon completion of the improvement to enable the DEQ to conduct an inspection; and (4) the Company and Mistras Arizona are prohibited from engaging in any chrome plating operations at the testing facility until they notify the DEQ that the improvements have been completed. The DEQ may seek relief if it determines that the improvements are not sufficient to prevent discharges. In April 2025, Mistras Arizona notified the DEQ that the improvements were completed, which the DEQ then inspected. Following the DEQ site visit, Mistras Arizona commenced its chrome plating operations on April 28, 2025. Mistras Arizona has been and intends to continue complying with the Superior Court's ruling. In the meantime, the DEQ Proceeding is ongoing. It is probable that additional remediation costs, as well as fines and penalties will be imposed related to the DEQ Proceeding. However, the Company is unable to estimate the range of loss that it may incur and whether these amounts will be material to the Company. In addition, Mistras Arizona’s operations in Phoenix are located at a leased site within the footprint of the Motorola 52nd Street Superfund Site (the “Motorola Site”). Mistras Arizona received a General Notice Letter from the US Environmental Protection Agency (the "EPA"), dated May 21, 2024, informing Mistras Arizona that the EPA has identified it as a potentially responsible party in relation to the Motorola Site. On April 29, 2025, the Company received a notice from the EPA requesting information regarding the improvements and other matters related to Phoenix testing facility. Mistras Arizona provided the EPA with the requested information in July 2025. Pension Related Contingencies Certain of the Company’s subsidiaries had significant reductions in their unionized workers in 2018. The collective bargaining agreements for the employees of these subsidiaries required contributions for these employees to two national multi-employer pension funds. The reduction in employees resulted in one of the Company's subsidiaries incurring a complete withdrawal to one of the pension funds under the Employee Retirement Income Security Act of 1974 ("ERISA"), which was fully satisfied in 2019. The Company has determined that the subsidiary is likely to incur partial or complete withdrawal liability to the other pension fund. The balance of the estimated total amount of this potential liability as of September 30, 2025 is approximately $2.2 million, which was incurred in 2018 and 2019.