Fair Value Of Financial Instruments (Fair Value Measurements On Differing Levels) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	$ 172,478us-gaap_AvailableForSaleSecurities	$ 172,202us-gaap_AvailableForSaleSecurities
Loans held-for-sale		617us-gaap_LoansReceivableHeldForSaleNet
Total assets measured at fair value on a recurring basis	172,478	172,202
Impaired Loans, Fair Value Disclosure	1,559dnbf_ImpairedLoansFairValueDisclosure	2,916dnbf_ImpairedLoansFairValueDisclosure
OREO and other repossessed property		100
Total assets measured at fair value on a nonrecurring basis	1,559	3,016
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	18	18
Total assets measured at fair value on a recurring basis	18	18
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	172,460	172,184
Total assets measured at fair value on a recurring basis	172,460	172,184
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans, Fair Value Disclosure	1,559	2,916
OREO and other repossessed property		100
Total assets measured at fair value on a nonrecurring basis	1,559	3,016
US Government Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	61,021	61,354
US Government Agency Obligations [Member] \| Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	61,021	61,354
Government Sponsored Entities (GSE) Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	60,871	66,723
Government Sponsored Entities (GSE) Mortgage-Backed Securities [Member] \| Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	60,871	66,723
Collateralized Mortgage Obligations GSE [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	19,087	20,011
Collateralized Mortgage Obligations GSE [Member] \| Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	19,087	20,011
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	20,431	13,102
Corporate Bonds [Member] \| Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	20,431	13,102
State And Municipal Tax-Exempt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	11,050	10,994
State And Municipal Tax-Exempt [Member] \| Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	11,050	10,994
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	18	18
Equity Securities [Member] \| Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for Sale Securities	$ 18	$ 18

Impaired Loans Fair Value Disclosure

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- Definition

Other Real Estate Owned and Other Repossessed Property, Fair Value Disclosure

+ References

No definition available.

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

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- Definition

Amount of loans held for sale, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

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-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

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-Name Accounting Standards Codification

-Topic 942

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