Document and Entity Information (USD $)	9 Months Ended
	Sep. 30, 2014	Nov. 03, 2014	Jun. 30, 2013
Entity Information [Line Items]
Entity Registrant Name	DYNEX CAPITAL INC
Entity Central Index Key	0000826675
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		54,736,663
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 518,414,092