Allowance for Credit Losses - By Credit Rating and Year of Origination (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Term Loans Amortized Cost Basis by Origination Year
Loans, gross	$ 1,943,326	$ 1,920,398
Consumer finance
Term Loans Amortized Cost Basis by Origination Year
2025/2024	37,287	147,822
2024/2023	138,388	108,397
2023/2022	99,351	124,597
2022/2021	112,386	56,176
2021/2020	49,730	19,700
Prior	24,994	10,101
Loans, gross	462,136	466,793
Consumer finance \| Very good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	5,267	30,285
2024/2023	27,967	16,322
2023/2022	15,081	20,641
2022/2021	19,214	10,362
2021/2020	9,651	8,353
Prior	11,271	3,831
Loans, gross	88,451	89,794
Consumer finance \| Good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	11,646	44,811
2024/2023	42,003	32,156
2023/2022	29,558	36,287
2022/2021	32,748	10,728
2021/2020	9,457	2,752
Prior	3,136	959
Loans, gross	128,548	127,693
Consumer finance \| Fairly good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	11,905	41,881
2024/2023	39,128	34,258
2023/2022	30,985	37,669
2022/2021	33,859	16,970
2021/2020	14,928	3,240
Prior	3,697	1,636
Loans, gross	134,502	135,654
Consumer finance \| Fair
Term Loans Amortized Cost Basis by Origination Year
2025/2024	7,189	25,796
2024/2023	24,500	21,278
2023/2022	19,755	24,379
2022/2021	21,700	13,260
2021/2020	11,480	3,674
Prior	4,506	2,194
Loans, gross	89,130	90,581
Consumer finance \| Marginal
Term Loans Amortized Cost Basis by Origination Year
2025/2024	1,280	5,049
2024/2023	4,790	4,383
2023/2022	3,972	5,621
2022/2021	4,865	4,856
2021/2020	4,214	1,681
Prior	2,384	1,481
Loans, gross	21,505	23,071
Consumer finance \| Automobiles
Term Loans Amortized Cost Basis by Origination Year
2025/2024	36,665	135,183
2024/2023	126,370	95,488
2023/2022	86,907	104,912
2022/2021	93,483	46,812
2021/2020	40,812	10,568
Prior	12,353	5,688
Loans, gross	396,590	398,651
Consumer finance \| Automobiles \| Very good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	5,000	22,161
2024/2023	20,311	10,039
2023/2022	9,061	7,971
2022/2021	7,018	2,359
2021/2020	1,991	426
Prior	371	77
Loans, gross	43,752	43,033
Consumer finance \| Automobiles \| Good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	11,291	40,296
2024/2023	37,641	25,730
2023/2022	23,331	29,455
2022/2021	26,222	9,402
2021/2020	8,233	1,574
Prior	1,454	334
Loans, gross	108,172	106,791
Consumer finance \| Automobiles \| Fairly good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	11,905	41,881
2024/2023	39,128	34,058
2023/2022	30,788	37,486
2022/2021	33,678	16,935
2021/2020	14,894	3,213
Prior	3,638	1,602
Loans, gross	134,031	135,175
Consumer finance \| Automobiles \| Fair
Term Loans Amortized Cost Basis by Origination Year
2025/2024	7,189	25,796
2024/2023	24,500	21,278
2023/2022	19,755	24,379
2022/2021	21,700	13,260
2021/2020	11,480	3,674
Prior	4,506	2,194
Loans, gross	89,130	90,581
Consumer finance \| Automobiles \| Marginal
Term Loans Amortized Cost Basis by Origination Year
2025/2024	1,280	5,049
2024/2023	4,790	4,383
2023/2022	3,972	5,621
2022/2021	4,865	4,856
2021/2020	4,214	1,681
Prior	2,384	1,481
Loans, gross	21,505	23,071
Consumer finance \| Marine and recreational vehicles
Term Loans Amortized Cost Basis by Origination Year
2025/2024	622	12,639
2024/2023	12,018	12,909
2023/2022	12,444	19,685
2022/2021	18,903	9,364
2021/2020	8,918	9,132
Prior	12,641	4,413
Loans, gross	65,546	68,142
Consumer finance \| Marine and recreational vehicles \| Very good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	267	8,124
2024/2023	7,656	6,283
2023/2022	6,020	12,670
2022/2021	12,196	8,003
2021/2020	7,660	7,927
Prior	10,900	3,754
Loans, gross	44,699	46,761
Consumer finance \| Marine and recreational vehicles \| Good
Term Loans Amortized Cost Basis by Origination Year
2025/2024	355	4,515
2024/2023	4,362	6,426
2023/2022	6,227	6,832
2022/2021	6,526	1,326
2021/2020	1,224	1,178
Prior	1,682	625
Loans, gross	20,376	20,902
Consumer finance \| Marine and recreational vehicles \| Fairly good
Term Loans Amortized Cost Basis by Origination Year
2024/2023		200
2023/2022	197	183
2022/2021	181	35
2021/2020	34	27
Prior	59	34
Loans, gross	$ 471	$ 479

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossByOriginationYearAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-79

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=cffi_ConsumerFinanceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditScoreFicoAxis=cffi_CreditRatingVeryGoodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditScoreFicoAxis=cffi_CreditRatingGoodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditScoreFicoAxis=cffi_CreditRatingFairlyGoodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditScoreFicoAxis=cffi_CreditRatingFairMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditScoreFicoAxis=cffi_CreditRatingMarginalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_AutomobileLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=cffi_MarineAndRecreationalVehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: