Loans and the Allowance for Loan Losses, Troubled Debt Restructuring (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015 Modification Contract	Mar. 31, 2014 Contract Modification
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	3
Recorded Investment Prior to Modification	$ 0	$ 468
Recorded Investment After Modification	0	468
Current Investment	0	467
Loans restructured and given below market rates	0	3
Principal forgiveness on all loans	0	0
Number of TDR loans that subsequently defaulted	0	1
Unfunded Commitments on TDRs	0opof_UnfundedCommitmentsOnTdrs	0opof_UnfundedCommitmentsOnTdrs
Mortgage Loans in Process of Foreclosure, Amount	99	446
Recorded Investment in Defaulting Loans	0	94
Total Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	3
Recorded Investment Prior to Modification	0	468
Recorded Investment After Modification	0	468
Current Investment	0	467
Recorded Investment in Defaulting Loans	0	94
Residential 1-4 Family [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	1
Recorded Investment Prior to Modification	0	276
Recorded Investment After Modification	0	276
Current Investment	0	275
Recorded Investment in Defaulting Loans	0	94
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications		0
Recorded Investment Prior to Modification		0
Recorded Investment After Modification		0
Current Investment		0
Recorded Investment in Defaulting Loans		0
Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	1
Recorded Investment Prior to Modification	0	103
Recorded Investment After Modification	0	103
Current Investment	0
Recorded Investment in Defaulting Loans		0
Second Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	1
Recorded Investment Prior to Modification	0	89
Recorded Investment After Modification	0	89
Current Investment	0
Recorded Investment in Defaulting Loans		0
Equity lines of credit for TDR disclosure [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications		0
Recorded Investment Prior to Modification		0
Recorded Investment After Modification		0
Recorded Investment in Defaulting Loans		0
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications		0
Recorded Investment Prior to Modification		0
Recorded Investment After Modification		0
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications		0
Recorded Investment Prior to Modification		0
Recorded Investment After Modification		$ 0

Number of loans modified and given below market rates.

No definition available.

Name:	opof_LoansRestructuredAndGivenBelowMarketRates
Namespace Prefix:	opof_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

No definition available.

+ Details

Name:	opof_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of outstanding commitments on restructured loans that have not been disbursed

+ References

No definition available.

+ Details

Name:	opof_UnfundedCommitmentsOnTdrs
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the amount of the write-down related to a troubled debt restructuring.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=opof_EquityLinesOfCreditForTdrDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=opof_TotalMortgageLoansOnRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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