Loans and the Allowance for Loan Losses, Troubled Debt Restructuring (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014 Contract Modification	Dec. 31, 2013 Modification Contract
Financing Receivable, Modifications [Line Items]
Number of Modifications	4	13
Recorded Investment Prior to Modification	$ 567	$ 5,529
Recorded Investment After Modification	567	5,529
Current Investment	554	5,480
Loans restructured and given below market rates	4	13
Principal forgiveness on all loans	0	0
Loans restructured given principal reductions	0	0
Loans restructured given principal reductions and below market rate	0	0
Financing Receivable, Modifications, Subsequent Defaults, Number of Contracts	2	3
Recorded investment in defaulting TDRs	389opof_RecordedInvestmentInDefaultingTdrs	2,243opof_RecordedInvestmentInDefaultingTdrs
Unfunded Commitments on TDRs	0opof_UnfundedCommitmentsOnTdrs	0opof_UnfundedCommitmentsOnTdrs
Total Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	4
Recorded Investment Prior to Modification	567
Recorded Investment After Modification	567
Current Investment	554
Residential 1-4 Family [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	2	8
Recorded Investment Prior to Modification	375	1,633
Recorded Investment After Modification	375	1,633
Current Investment	366	1,620
Financing Receivable, Modifications, Subsequent Defaults, Number of Contracts	2	2
Recorded investment in defaulting TDRs	389	181
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0	3
Recorded Investment Prior to Modification	0	3,665
Recorded Investment After Modification	0	3,665
Current Investment	0	3,657
Financing Receivable, Modifications, Subsequent Defaults, Number of Contracts	0	1
Recorded investment in defaulting TDRs	0	2,062
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	102
Second Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	1	2
Recorded Investment Prior to Modification	89	231
Recorded Investment After Modification	89	231
Current Investment	86	203
Home Equity Line of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0
Recorded Investment Prior to Modification	0
Recorded Investment After Modification	0
Current Investment	0
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0
Recorded Investment Prior to Modification	0
Recorded Investment After Modification	0
Current Investment	0
Consumer Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0
Recorded Investment Prior to Modification	0
Recorded Investment After Modification	0
Current Investment	0
Other Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications	0
Recorded Investment Prior to Modification	0
Recorded Investment After Modification	0
Current Investment	$ 0

Number of loans modified and given below market rates.

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- Definition

Number of modifications given principal reductions.

+ References

No definition available.

+ Details

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Number of modifications given both principal reductions and a below-market rate for debt with similar risk characteristics.

+ References

No definition available.

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- Definition

The recorded investment in loans that defaulted within twelve months of restructuring.

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- 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

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

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- Definition

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

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- 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

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- 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

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- Definition

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

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