Loans and Related Allowance for Loan Losses (Allowance for Loan Losses on Loans, Excluding PCI Loans, by Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	$ 8,983
Provision Allocation	(325)
Allowance for loan losses, End of Period	8,429	$ 8,983
Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	8,983	8,969
Provision Allocation	325
Charge-offs	(1,644)	(481)
Recoveries	765	495
Allowance for loan losses, End of Period	8,429	8,983
Loans [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	5,660	7,670
Provision Allocation	832	(2,028)
Charge-offs	(667)	(216)
Recoveries	465	234
Allowance for loan losses, End of Period	6,290	5,660
Loans [Member] \| Commercial Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	1,894	1,139
Provision Allocation	626	751
Charge-offs	(724)	(45)
Recoveries	184	49
Allowance for loan losses, End of Period	1,980	1,894
Loans [Member] \| Consumer Installment Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	152	110
Provision Allocation	99	53
Charge-offs	(253)	(220)
Recoveries	116	209
Allowance for loan losses, End of Period	114	152
Loans [Member] \| All Other Loans [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	12	3
Provision Allocation	(5)	6
Charge-offs
Recoveries		3
Allowance for loan losses, End of Period	7	12
Loans [Member] \| Unallocated [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	1,265	47
Provision Allocation	(1,227)	1,218
Charge-offs
Recoveries
Allowance for loan losses, End of Period	38	1,265
Loans [Member] \| 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	2,281	3,466
Provision Allocation	315	(1,252)
Charge-offs	(178)	(89)
Recoveries	267	156
Allowance for loan losses, End of Period	2,685	2,281
Loans [Member] \| Commercial [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	1,810	2,423
Provision Allocation	583	(647)
Charge-offs	(277)
Recoveries	80	34
Allowance for loan losses, End of Period	2,196	1,810
Loans [Member] \| 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	1,161	1,247
Provision Allocation	24	3
Charge-offs	(212)	(127)
Recoveries	71	38
Allowance for loan losses, End of Period	1,044	1,161
Loans [Member] \| Second Mortgages [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	20	24
Provision Allocation	53	(10)
Charge-offs
Recoveries	6	6
Allowance for loan losses, End of Period	79	20
Loans [Member] \| Multifamily [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	371	496
Provision Allocation	(164)	(125)
Charge-offs
Recoveries	41
Allowance for loan losses, End of Period	248	371
Loans [Member] \| Agriculture [Member] \| Mortgage Loans on Real Estate [Member]
Noncancelable Obligations Future Minimum Payments Due [Line Items]
Allowance for loan losses, Beginning of Period	17	14
Provision Allocation	21	3
Charge-offs
Recoveries
Allowance for loan losses, End of Period	$ 38	$ 17

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:	srt_MortgageLoansOnRealEstateLoanTypeAxis=esxb_NonCoveredLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- 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: