Name:	opof_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnDebitCardExpense
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The amount of increase (decrease) to debit card revenue from the retrospective reclassification of debit card expenses against debit card revenue to create a net presentation resulting from the effect of a new accounting principle applied in the period of adoption.

No definition available.

Name:	opof_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnDebitCardRevenue
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Number of branch offices operated by the entity.

No definition available.

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

Number of operating subsidiaries held by the entity.

No definition available.

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

Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	opof_TaxCutsAndJobsActOf2017ReclassificationFromAOCIToRetainedEarningsTaxEffect
Namespace Prefix:	opof_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

No definition available.

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

The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

No definition available.

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

- References

No definition available.

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

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=opof_AccountingStandardsUpdate201802Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_AccumulatedOtherComprehensiveIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_RetainedEarningsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: