Loans and the Allowance for Loan Losses, Troubled Debt Restructuring (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014 Modification Contract	Mar. 31, 2013 Contract
Financing Receivable, Modifications [Line Items]
Number of Modifications	3	2
Recorded Investment Prior to Modification	$ 468	$ 598
Recorded Investment After Modification	468	598
Current Investment	467	598
Restructurings that Subsequently Defaulted [Abstract]
Recorded Investment in Defaulting Loans		1,855
Loans restructured and given below market rates	3	2
Principal forgiveness on all loans	0	0
Number of TDR loans that subsequently defaulted	1	1
Unfunded Commitments on TDRs	0	0
Total Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	3	2
Recorded Investment Prior to Modification	468	598
Recorded Investment After Modification	468	598
Current Investment	467	598
Restructurings that Subsequently Defaulted [Abstract]
Recorded Investment in Defaulting Loans	94	1,855
Total Mortgage Loans on Real Estate [Member] \| Residential 1-4 Family [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	1	1
Recorded Investment Prior to Modification	276	391
Recorded Investment After Modification	276	391
Current Investment	275	391
Restructurings that Subsequently Defaulted [Abstract]
Recorded Investment in Defaulting Loans	94
Total Mortgage Loans on Real Estate [Member] \| Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications		1
Recorded Investment Prior to Modification		207
Recorded Investment After Modification		207
Current Investment		207
Restructurings that Subsequently Defaulted [Abstract]
Recorded Investment in Defaulting Loans		1,855
Total Mortgage Loans on Real Estate [Member] \| Second Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	1
Recorded Investment Prior to Modification	89
Recorded Investment After Modification	89
Current Investment	89
Total Mortgage Loans on Real Estate [Member] \| Construction Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	1
Recorded Investment Prior to Modification	103
Recorded Investment After Modification	103
Current Investment	$ 103

Name:	opof_FinancingReceivableModificationsSubsequentDefaultRecordedInvestmentAbstract
Namespace Prefix:	opof_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of loans modified and given below market rates.

+ References

No definition available.

+ Details

Name:	opof_LoansRestructuredAndGivenBelowMarketRates
Namespace Prefix:	opof_
Data Type:	xbrli:integerItemType
Balance Type:	na
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=28368275&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=28368275&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