Document And Entity Information
 3 Months Ended
Nov. 30, 2012
Dec. 19, 2012
Document and Entity Information [Abstract]    
Entity Registrant Name SHAW GROUP INC  
Document Type 10-Q  
Current Fiscal Year End Date --08-31  
Entity Common Stock, Shares Outstanding   66,663,781
Amendment Flag false  
Entity Central Index Key 0000914024  
Entity Current Reporting Status Yes  
Entity Voluntary Filers No  
Entity Filer Category Large Accelerated Filer  
Entity Well-known Seasoned Issuer Yes  
Document Period End Date Nov. 30, 2012  
Document Fiscal Year Focus 2013  
Document Fiscal Period Focus Q1