Description of Business and Summary of Significant Accounting Policies, Interest-bearing Deposits in Banks (Details)	12 Months Ended
Dec. 31, 2024
Interest-Bearing Deposits in Banks [Abstract]
Maturity period of interest bearing deposits	1 year

Maturity period of interest bearing deposits, which are carried at cost in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	opof_MaturityPeriodOfInterestBearingDeposits
Namespace Prefix:	opof_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration