v2.4.0.6
Document and Entity Information
9 Months Ended
Sep. 30, 2012
Nov. 05, 2012
Document and Entity Information [Abstract]    
Entity Registrant Name BankFinancial CORP  
Entity Central Index Key 0001303942  
Document Type 10-Q  
Document Fiscal Period Focus Q3  
Document Period End Date Sep. 30, 2012  
Amendment Flag false  
Document Fiscal Year Focus 2012  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Common Stock, Shares Outstanding   21,072,966