Name:	cfnb_NonInterestBearingDepositsAbstract
Namespace Prefix:	cfnb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of interest-bearing demand deposits as a percentage of total deposits.

No definition available.

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

Represents the percentage of interest-bearing savings deposits as a percentage of total deposits.

No definition available.

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

Represents the percentage of interest-bearing time certificates of deposit as a percentage of total deposits.

No definition available.

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

Represents the percentage of non-interest-bearing demand deposits as a percentage of total deposits.

No definition available.

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

Represents the total percentage of total deposits.

No definition available.

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

The amount of money in accounts that may bear interest and that the depositor is entitled to withdraw at any time without prior notice.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_DemandDepositAccounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

Name:	us-gaap_Deposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

Name:	us-gaap_DepositsSavingsDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The aggregate amount of all domestic and foreign noninterest-bearing deposits liabilities held by the entity.

Name:	us-gaap_NoninterestBearingDepositLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.