Name:	cffi_BusinessCombinationAcquisitionRelatedCostsAfterIncomeTaxes
Namespace Prefix:	cffi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of ceiling on borrowings from another operating segment of the reporting entity.

No definition available.

Name:	cffi_InterSegmentInterestDebtInstrumentCeilingPercent
Namespace Prefix:	cffi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage points added to the reference rate to compute the variable rate on borrowing from another operating segment of the reporting entity.

No definition available.

Name:	cffi_IntersegmentInterestDebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	cffi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Floor variable rate of borrowing from another operating segment of the reporting entity.

No definition available.

Name:	cffi_IntersegmentInterestDebtInstrumentFloorVariableRate
Namespace Prefix:	cffi_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Number of intersegment lines of credit.

No definition available.

Name:	cffi_NumberOfIntersegmentLinesOfCredit
Namespace Prefix:	cffi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460

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Data Type:	xbrli:monetaryItemType
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_SegmentReportingInformationLineItems
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