Summary of Significant Accounting Policies - Paycheck Protection Program (Details)	6 Months Ended
Jun. 30, 2020
Minimum
Fees as percentage of principal amount (as a percent)	1.00%
Maximum
Fees as percentage of principal amount (as a percent)	5.00%

Percentage of fees the Corporation received from the Small Business Administration (SBA) of the principal amount of each loan originated under the Paycheck Protection Program (PPP).

No definition available.

Name:	cffi_PercentageOfFeesFromSmallBusinessAdministration
Namespace Prefix:	cffi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration