Document and Entity Information (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
May 31, 2013
Aug. 01, 2013
Nov. 30, 2012
Document and Entity Information      
Entity Registrant Name Mistras Group, Inc.    
Entity Central Index Key 0001436126    
Document Type 10-K    
Document Period End Date May 31, 2013    
Amendment Flag false    
Current Fiscal Year End Date --05-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Accelerated Filer    
Entity Public Float     $ 364.0
Entity Common Stock, Shares Outstanding   28,211,006  
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus FY