Subsequent Events Terminated Swaps (Details) (Subsequent Event [Member], USD $)	1 Months Ended
Nov. 08, 2013
Subsequent Event [Member]
Subsequent Event [Line Items]
Terminated derivative instruments	$ 902,000

Notional amount of derivative instruments terminated during the period.

No definition available.

Name:	dx_Terminatedderivativeinstruments
Namespace Prefix:	dx_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration