Loans and the Allowance for Loan Losses, Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($) Loan	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Loan Contract	Sep. 30, 2018 USD ($) Contract	Dec. 31, 2018 USD ($) Loan
Receivables [Abstract]
Number of Modifications \| Contract			3	0
Outstanding commitments on TDR's	$ 0		$ 0		$ 0
Defaulting TDR's within twelve months of restructuring	$ 0	$ 0	$ 0	$ 0
Mortgage Loans on Real Estate [Member] \| Residential 1-4 Family [Member]
Receivables [Abstract]
Number of loans in process for disclosure \| Loan	0		0		0

The number of recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

No definition available.

+ Details

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Namespace Prefix:	opof_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524

+ Details

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

- Definition

Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554

+ Details

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

- References

No definition available.

+ Details

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Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=opof_OneToFourFamilyResidentialMember
Namespace Prefix:
Data Type:	na
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