v3.26.1
Document and Entity Information Document and Entity Information - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Jul. 24, 2026
Document Information [Line Items]          
Document Type     10-Q    
Document Quarterly Report     true    
Document Period End Date     Jun. 30, 2026    
Current Fiscal Year End Date     --12-31    
Document Transition Report     false    
Entity File Number     001-09819    
Entity Registrant Name     DYNEX CAPITAL, INC.    
Entity Incorporation, State or Country Code     VA    
Entity Tax Identification Number     52-1549373    
Entity Address, Address Line One     140 Eastshore Drive    
Entity Address, Address Line Two     Suite 100    
Entity Address, City or Town     Glen Allen,    
Entity Address, State or Province     VA    
Entity Address, Postal Zip Code     23059-5755    
City Area Code     (804)    
Local Phone Number     217-5800    
Entity Current Reporting Status     Yes    
Entity Interactive Data Current     Yes    
Entity Filer Category     Large Accelerated Filer    
Entity Small Business     false    
Entity Emerging Growth Company     false    
Entity Shell Company     false    
Entity Central Index Key     0000826675    
Document Fiscal Year Focus     2026    
Document Fiscal Period Focus     Q2    
Amendment Flag     false    
Entity Common Stock, Shares Outstanding         247,429,551
Other comprehensive income (loss) $ (865) $ 4,064 $ (1,013) $ 23,454  
Common Stock          
Document Information [Line Items]          
Title of 12(b) Security     Common Stock, par value $0.01 per share    
Trading Symbol     DX    
Security Exchange Name     NYSE    
Series C Preferred Stock          
Document Information [Line Items]          
Title of 12(b) Security     6.900% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock, par value $0.01 per share    
Trading Symbol     DXPRC    
Security Exchange Name     NYSE