v3.10.0.1
Document and Entity Information Document - shares
6 Months Ended
Jun. 30, 2018
Aug. 01, 2018
Document and Entity Information [Abstract]    
Entity Registrant Name Redfin Corp  
Entity Central Index Key 0001382821  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Document Type 10-Q  
Document Period End Date Jun. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   88,704,459