v3.10.0.1
Document and Entity Information Document - USD ($)
12 Months Ended
Dec. 31, 2018
Mar. 07, 2019
Jun. 30, 2018
Document and Entity Information [Abstract]      
Entity Registrant Name Ellington Residential Mortgage REIT    
Entity Central Index Key 0001560672    
Current Fiscal Year End Date --12-31    
Entity Filer Category Accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company false    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   12,467,103  
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Shell Company false    
Entity Current Reporting Status Yes    
Entity Public Float     $ 103,318,920