Name:	dx_InvestmentsUnamortizedDiscount
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The remaining amount of investment premium originally recognized at the purchase date of the instrument that has yet to be amortized.

No definition available.

Name:	dx_InvestmentsUnamortizedPremium
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the current weighted-average gross interest rate earned on this type of MBS in the investment portfolio as of the period indicated. The gross interest rate of each MBS within the portfolio is weighted based on its current outstanding notional or par balance. The current outstanding notional or par balance for each MBS consists of the total of all principal balances remaining on the mortgage loans underlying each MBS.

No definition available.

Name:	dx_InvestmentsWeightedAverageCouponRate
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Notional balance of non-Agency interest only securities owned by the Company that does not carry a guarantee of payment from a government sponsored entity.

No definition available.

Name:	dx_NotionalBalanceOfNonAgencyInterestOnlySecurities
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This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

No definition available.

Name:	us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix:	us-gaap_
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Period Type:	instant

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 13, 19

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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This item represents the gross unrealized losses for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

No definition available.

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For investments which are quantified by principal amount, the principle balance held at close of period.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 6

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-URI http://asc.fasb.org/extlink&oid=6955306&loc=d3e611322-123010

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-Name Accounting Standards Codification

-Topic 946

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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-Section 25

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-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

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-URI http://asc.fasb.org/extlink&oid=6505594

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 12

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 35

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=16383099&loc=d3e24584-111560

Name:	us-gaap_InvestmentsFairValueDisclosure
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The cash outflow for the purchase of securities issued by a governmental agency or corporation (for example, GNMA or FHLMC) or by private issuers (for example, banks and mortgage banking enterprises) secured by and repaid from underlying mortgages, which were designated as available for sale when acquired.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Section 45

-Paragraph 13

-Subparagraph (a)

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-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3521-108585

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-Topic 230

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 26, 31

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.