v3.7.0.1
Document and Entity Information - shares
9 Months Ended
Jun. 30, 2017
Aug. 01, 2017
Document and Entity Information    
Entity Registrant Name LIQUIDITY SERVICES INC  
Entity Central Index Key 0001235468  
Document Type 10-Q  
Document Period End Date Jun. 30, 2017  
Amendment Flag false  
Current Fiscal Year End Date --09-30  
Entity Current Reporting Status Yes  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   31,503,349
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q3