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Represents the percent decrease in dividends from a mutual fund investment.

+ References

No definition available.

+ Details

Name:	cfnb_ReductionInDividendFromMutualFundInvestmentPercentage
Namespace Prefix:	cfnb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

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Balance Type:	credit
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- Definition

The fair value of available-for-sale securities that serve as collateral for borrowings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5086-111524

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease), resulting in a loss, in the difference between the fair value and the carrying value, or in the comparative fair values, of securities held at each balance sheet date, that was included in earnings for the period.

+ References

No definition available.

+ Details

Name:	us-gaap_UnrealizedLossOnSecurities
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Note 7 - Securities Available-For-Sale (Details) (USD $)	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	May 31, 2014
Note 7 - Securities Available-For-Sale (Details) [Line Items]
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 0		$ 0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	91,000	45,000
Reduction In Dividend From Mutual Fund Investment, Percentage				11.00%
Unrealized Loss on Securities	48,000
Early Call Provision of a Corporate Bond [Member]
Note 7 - Securities Available-For-Sale (Details) [Line Items]
Available-for-sale Securities Pledged as Collateral	$ 26,800,000	$ 8,000,000