Disposal Group Including Discontinued Operation Customer Deposits

No definition available.

Name:	fcbc_DisposalGroupIncludingDiscontinuedOperationCustomerDeposits
Namespace Prefix:	fcbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number Of Branches Sold.

+ References

No definition available.

+ Details

Name:	fcbc_NumberOfBranchesSold
Namespace Prefix:	fcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of operating branches of bank.

+ References

No definition available.

+ Details

Name:	fcbc_NumberOfOperatingBranchesOfBank
Namespace Prefix:	fcbc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of liabilities recognized recorded in a transaction with the acquiree for each transaction that is recognized separately from the acquisition of assets and assumptions of liabilities in the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(3)
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

+ Details

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

- Definition

Amount classified as accounts, notes and loans receivable attributable to disposal group held for sale or disposed of.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2941-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721533-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721673-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e1107-107759

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=fcbc_BankOfAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=fcbc_SouthwesternVirginiaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=fcbc_FirstBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=stpr_NC
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events - Additional Information (Detail)	Mar. 04, 2016 USD ($) Branch	Oct. 24, 2014 USD ($) Branch
Bank of America
Subsequent Event [Line Items]
Number of operating branches \| Branch		7
Deposit held on acquisition date by acquiree \| $		$ 318,880,000
Bank of America \| Southwestern Virginia
Subsequent Event [Line Items]
Number of operating branches \| Branch		6
Subsequent Event \| Bank of America \| Southwestern Virginia
Subsequent Event [Line Items]
Number of operating branches \| Branch	7
Deposit held on acquisition date by acquiree \| $	$ 150,000,000
Subsequent Event \| First Bank \| Southeastern, Coastal region of North Carolina
Subsequent Event [Line Items]
Number of operating branches sold \| Branch	6
Deposit assumed by the buyer \| $	$ 130,000,000
Subsequent Event \| First Bank \| Southeastern, Coastal region of North Carolina \| Maximum
Subsequent Event [Line Items]
Loan assumed by the buyer \| $	$ 175,000,000