Fair Value Measurements, Recurring and Nonrecurring Basis (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Available-for-sale securities [Abstract]
Fair Value	$ 321,645	$ 329,456
Recurring [Member]
Available-for-sale securities [Abstract]
Obligations of U.S. Government agencies	36,416	37,088
Obligations of state and political subdivisions	48,262	43,774
Mortgage-backed securities	235,274	247,355
Money market investments	697	541
Corporate Bonds	996	698
Fair Value	321,645	329,456
Nonrecurring [Member]
Mortgage loans on real estate: [Abstract]
Residential 1-4 family	2,966	3,009
Commercial	2,876	2,271
Second mortgages	971	42
Total mortgage loans on real estate	6,813	5,322
Commercial loans		64
Total		5,386
Foreclosed assets [Abstract]
Residential 1-4 family	431	676
Commercial	1,825	2,094
Construction	3,765	3,804
Total	6,021	6,574
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring [Member]
Available-for-sale securities [Abstract]
Obligations of U.S. Government agencies	0	0
Obligations of state and political subdivisions	0	0
Mortgage-backed securities	0	0
Money market investments	0	0
Corporate Bonds	0	0
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Nonrecurring [Member]
Mortgage loans on real estate: [Abstract]
Residential 1-4 family	0	0
Commercial	0	0
Second mortgages	0	0
Total mortgage loans on real estate	0	0
Commercial loans		0
Total		0
Foreclosed assets [Abstract]
Residential 1-4 family	0	0
Commercial	0	0
Construction	0	0
Total	0	0
Significant Other Observable Inputs (Level 2) [Member] \| Recurring [Member]
Available-for-sale securities [Abstract]
Obligations of U.S. Government agencies	36,416	37,088
Obligations of state and political subdivisions	48,262	43,774
Mortgage-backed securities	235,274	247,355
Money market investments	697	541
Corporate Bonds	996	698
Fair Value	321,645	329,456
Significant Other Observable Inputs (Level 2) [Member] \| Nonrecurring [Member]
Mortgage loans on real estate: [Abstract]
Residential 1-4 family	0	0
Commercial	0	0
Second mortgages	0	0
Total mortgage loans on real estate	0	0
Commercial loans		0
Total		0
Foreclosed assets [Abstract]
Residential 1-4 family	0	0
Commercial	0	0
Construction	0	0
Total	0	0
Significant Unobservable Inputs (Level 3) [Member] \| Recurring [Member]
Available-for-sale securities [Abstract]
Obligations of U.S. Government agencies	0	0
Obligations of state and political subdivisions	0	0
Mortgage-backed securities	0	0
Money market investments	0	0
Corporate Bonds	0	0
Fair Value	0	0
Significant Unobservable Inputs (Level 3) [Member] \| Nonrecurring [Member]
Mortgage loans on real estate: [Abstract]
Residential 1-4 family	2,966	3,009
Commercial	2,876	2,271
Second mortgages	971	42
Total mortgage loans on real estate	6,813	5,322
Commercial loans		64
Total		5,386
Foreclosed assets [Abstract]
Residential 1-4 family	431	676
Commercial	1,825	2,094
Construction	3,765	3,804
Total	$ 6,021	$ 6,574

The fair value disclosure mortgage loans on commercial real estate.

No definition available.

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

- Details

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

- Definition

Fair value disclosure of total foreclosed assets at the end of the period.

+ References

No definition available.

+ Details

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

- Definition

Fair value disclosure of mortgage loans on foreclosed commercial real estate.

+ References

No definition available.

+ Details

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

- Definition

Fair value disclosure of foreclosed construction loans.

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Fair value disclosure of mortgage loans on commercial real estate.

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

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

- Definition

Fair value disclosure of mortgage loans on 1-4 family residential real estate loans.

+ References

No definition available.

+ Details

Name:	opof_Residential1To4FamilyFairValueDisclosure
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value disclosure of mortgage loans on foreclosed 1-4 family residential real estate loans.

+ References

No definition available.

+ Details

Name:	opof_Residential1To4FamilyForeclosedFairValueDisclosure
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value disclosure of loans on second mortgages.

+ References

No definition available.

+ Details

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

- Definition

The fair value disclosure of total mortgage loans on real estate.

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

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

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

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

- Details

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

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594

+ Details

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

- Definition

+ References

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

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-DEP

-Paragraph 15

-IssueDate 2006-05-01

-Chapter 7

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Mortgage-Backed Securities

-URI http://asc.fasb.org/extlink&oid=6517959

+ Details

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

- Definition

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph b

-Article 5

+ Details

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