Loans and Related Allowance for Loan Losses (Allowance for Loan Losses on Loans, Excluding PCI Loans, by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	$ 12,340	$ 8,429
Provision Allocation	(1,400)	3,300
Charge-offs	(246)	(94)
Recoveries	134	184
Allowance for loan losses, End of Period	10,828	11,819
Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	10,317	6,290
Provision Allocation	(2,778)	2,477
Recoveries	69	144
Allowance for loan losses, End of Period	7,608	8,911
Commercial Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	1,897	1,980
Provision Allocation	379	582
Charge-offs	(167)	(19)
Recoveries	24	3
Allowance for loan losses, End of Period	2,133	2,546
Consumer Installment Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	119	114
Provision Allocation	86	35
Charge-offs	(79)	(75)
Recoveries	41	37
Allowance for loan losses, End of Period	167	111
All Other Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	7	7
Provision Allocation		1
Allowance for loan losses, End of Period	7	8
Unallocated [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period		38
Provision Allocation	913	205
Allowance for loan losses, End of Period	913	243
Residential 1-4 Family [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	2,638	2,685
Provision Allocation	(772)	234
Recoveries	38	16
Allowance for loan losses, End of Period	1,904	2,935
Commercial [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	4,568	2,196
Provision Allocation	(1,059)	2,000
Recoveries	3	44
Allowance for loan losses, End of Period	3,512	4,240
Construction and Land Development [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	2,545	1,044
Provision Allocation	(758)	227
Recoveries	20	83
Allowance for loan losses, End of Period	1,807	1,354
Second Mortgages [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	18	79
Provision Allocation	(7)	(10)
Recoveries	8	1
Allowance for loan losses, End of Period	19	70
Multifamily [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	508	248
Provision Allocation	(201)	19
Allowance for loan losses, End of Period	307	267
Agriculture [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	40	38
Provision Allocation	19	7
Allowance for loan losses, End of Period	$ 59	$ 45

Noncancelable obligations future minimum payments due.

No definition available.

Name:	esxb_NoncancelableObligationsFutureMinimumPaymentsDueLineItems
Namespace Prefix:	esxb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=118939070&loc=d3e15032-111544

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

+ Details

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

- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

+ Details

Name:	us-gaap_ProvisionForLoanAndLeaseLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_SecondMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=srt_MultifamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=esxb_AgricultureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: