Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Financial assets [Abstract]
Securities available-for-sale	$ 158,147	$ 329,456
Securities held-to-maturity	94,838
Carrying Value [Member]
Financial assets [Abstract]
Cash and Cash Equivalents	66,714	42,317
Securities available-for-sale	158,147	329,456
Securities held-to-maturity	93,819	570
Restricted securities	2,378	2,562
Loans, net of allowances for loan losses	473,187	463,809
Bank owned life insurance	22,472	21,824
Accrued Interest Receivable	2,340	2,420
Financial liabilities [Abstract]
Deposits	730,824	753,816
Federal Funds Purchased	0	0
Overnight repurchase agreements	37,020	35,946
Term repurchase agreements	411	1,280
Federal Home Loan Bank advances	25,000	25,000
Accrued interest payable	350	439
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets [Abstract]
Cash and Cash Equivalents	66,714	42,317
Securities available-for-sale	0	0
Securities held-to-maturity	0	0
Restricted securities	0	0
Loans, net of allowances for loan losses	0	0
Bank owned life insurance	0	0
Accrued Interest Receivable	0	0
Financial liabilities [Abstract]
Deposits	0	0
Federal Funds Purchased	0	0
Overnight repurchase agreements	0	0
Term repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Accrued interest payable	0	0
Significant Other Observable Inputs (Level 2) [Member]
Financial assets [Abstract]
Cash and Cash Equivalents	0	0
Securities available-for-sale	158,147	329,456
Securities held-to-maturity	94,838	574
Restricted securities	2,378	2,562
Loans, net of allowances for loan losses	0	0
Bank owned life insurance	22,472	21,824
Accrued Interest Receivable	2,340	2,420
Financial liabilities [Abstract]
Deposits	734,017	757,923
Federal Funds Purchased	0	0
Overnight repurchase agreements	37,020	35,946
Term repurchase agreements	411	1,282
Federal Home Loan Bank advances	27,814	28,681
Accrued interest payable	350	439
Significant Unobservable Inputs (Level 3) [Member]
Financial assets [Abstract]
Cash and Cash Equivalents	0	0
Securities available-for-sale	0	0
Securities held-to-maturity	0	0
Restricted securities	0	0
Loans, net of allowances for loan losses	475,990	466,492
Bank owned life insurance	0	0
Accrued Interest Receivable	0	0
Financial liabilities [Abstract]
Deposits	0	0
Federal Funds Purchased	0	0
Overnight repurchase agreements	0	0
Term repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Accrued interest payable	0	0
Impaired Loans, Residential 1-4 Family Real Estate [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	3,001	3,009
Impaired Loans, Residential 1-4 Family Real Estate [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	13.00%	4.75%
Liquidation Discount	6.50%	0.00%
Impaired Loans, Residential 1-4 Family Real Estate [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	14.00%	6.00%
Liquidation Discount	6.50%	5.00%
Impaired Loans, Residential 1-4 Family Real Estate [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	13.00%	6.00%
Liquidation Discount	6.50%	5.00%
Impaired Loans, Commercial Real Estate [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	2,201	2,271
Impaired Loans, Commercial Real Estate [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	5.00%	0.00%
Liquidation Discount	10.00%
Impaired Loans, Commercial Real Estate [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	14.00%	6.00%
Liquidation Discount	10.00%
Impaired Loans, Commercial Real Estate [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%	4.00%
Liquidation Discount	10.00%
Impaired Loans, Construction Loans [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	2,396
Impaired Loans, Construction Loans [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%
Liquidation Discount	15.50%
Impaired Loans, Construction Loans [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%
Liquidation Discount	15.50%
Impaired Loans, Construction Loans [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%
Liquidation Discount	15.50%
Impaired Loans, Second Mortgages [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	0	42
Impaired Loans, Second Mortgages [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	0.00%
Liquidation Discount	0.00%
Impaired Loans, Second Mortgages [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	0.00%
Liquidation Discount	0.00%
Impaired Loans, Second Mortgages [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	0.00%
Liquidation Discount	0.00%
Impaired Loans, Commercial Loans [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value		64
Foreclosed Assets, Residential 1-4 Family [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	216	676
Foreclosed Assets, Residential 1-4 Family [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%
Foreclosed Assets, Residential 1-4 Family [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%	10.00%
Foreclosed Assets, Residential 1-4 Family [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%
Foreclosed Assets, Commercial [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	2,444	2,094
Foreclosed Assets, Commercial [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%
Foreclosed Assets, Commercial [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%	10.00%
Foreclosed Assets, Commercial [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%
Foreclosed Assets, Construction [Member] \| Market Comparables [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value	$ 3,722	$ 3,804
Foreclosed Assets, Construction [Member] \| Market Comparables [Member] \| Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%
Foreclosed Assets, Construction [Member] \| Market Comparables [Member] \| Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	10.00%	10.00%
Foreclosed Assets, Construction [Member] \| Market Comparables [Member] \| Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Selling costs (in hundredths)	6.00%	6.00%

No definition available.

Name:	opof_AccruedInterestPayableFairValueDisclosure
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

Name:	opof_OvernightRepurchaseAgreementsFairValueDisclosure
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

Name:	opof_TermRepurchaseAgreementsFairValueDisclosure
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_AssetsFairValueDisclosureAbstract
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

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 includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 7

-Footnote 1

-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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 8

-Footnote 2

-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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 7, 8, 9, 10

-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.

+ Details

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

- 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 element represents the portion of a 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 the amount that could be realized under a life insurance contract or contracts owned by the Company as of the date of the statement of financial position. Such Company-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Surrender Value

-URI http://asc.fasb.org/extlink&oid=6507153

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 88-5

-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 FASB Technical Bulletin (FTB)

-Number 85-4

-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.

+ Details

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

- Definition

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Percentage of adjustment to the observed price for a similar asset or liability when an identical transaction does not exist, used as an input to measure fair value.

+ 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 (bbb)

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

+ Details

Name:	us-gaap_FairValueInputsComparabilityAdjustments
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Adjustment to the discount rate used to measure fair value for lack of ability to convert business interests into cash quickly.

+ 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 (bbb)

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

+ Details

Name:	us-gaap_FairValueInputsDiscountForLackOfMarketability
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount borrowed by a bank, at the federal funds rate, from another bank to meet its reserve requirements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(1))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph 1

-Article 9

+ Details

Name:	us-gaap_FederalFundsPurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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 17

-IssueDate 2006-05-01

-Chapter 15

-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.

+ Details

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

- Definition

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 33

-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 Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 7-11

-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.

+ Details

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

- Details

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

- Definition

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

-URI http://asc.fasb.org/extlink&oid=6517073

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 4

-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.

+ Details

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