Loans and the Allowance for Loan Losses, Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 16,341	$ 22,466
Without Valuation Allowance	7,644	11,414
With Valuation Allowance	6,784	8,371
Associated Allowance	702	1,693
Average Recorded Investment	17,732	19,201
Interest Income Recognized	656	681
Total Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	16,327	22,301
Without Valuation Allowance	7,630	11,265
With Valuation Allowance	6,784	8,356
Associated Allowance	702	1,693
Average Recorded Investment	17,669	19,140
Interest Income Recognized	655	674
Residential 1-4 Family [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	2,898	5,713
Without Valuation Allowance	2,083	1,542
With Valuation Allowance	646	4,009
Associated Allowance	91	1,383
Average Recorded Investment	4,099	5,152
Interest Income Recognized	126	102
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	11,766	12,905
Without Valuation Allowance	4,729	6,882
With Valuation Allowance	5,322	4,300
Associated Allowance	163	307
Average Recorded Investment	10,669	10,631
Interest Income Recognized	449	591
Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	1,157	3,309
Without Valuation Allowance	623	2,545
With Valuation Allowance	534	0
Associated Allowance	270	0
Average Recorded Investment	2,431	2,798
Interest Income Recognized	55	0
Second Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	506	374
Without Valuation Allowance	195	296
With Valuation Allowance	282	47
Associated Allowance	178	3
Average Recorded Investment	470	462
Interest Income Recognized	25	(19)
Equity Line of Credit [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	0
Without Valuation Allowance	0	0
With Valuation Allowance	0	0
Associated Allowance	0	0
Average Recorded Investment	0	97
Interest Income Recognized	0	0
Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	0	150
Without Valuation Allowance	0	149
With Valuation Allowance	0	0
Associated Allowance	0	0
Average Recorded Investment	37	44
Interest Income Recognized	0	6
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	14	15
Without Valuation Allowance	14	0
With Valuation Allowance	0	15
Associated Allowance	0	0
Average Recorded Investment	26	17
Interest Income Recognized	$ 1	$ 1

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

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5258-111524

+ Details

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

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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