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Document And Entity Information - USD ($)
 12 Months Ended
Sep. 30, 2016
Dec. 07, 2016
Mar. 31, 2016
Document And Entity Information [Abstract]      
Entity Registrant Name IES Holdings, Inc.    
Entity Central Index Key 0001048268    
Document Type 10-K    
Document Period End Date Sep. 30, 2016    
Amendment Flag false    
Document Fiscal Year Focus 2016    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --09-30    
Entity Filer Category Accelerated Filer    
Entity Common Stock, Shares Outstanding   21,456,523  
Entity Well-known Seasoned Issuer No    
Entity Public Float     $ 113,458,469
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Trading Symbol IESC