Description of Business and Summary of Significant Accounting Policies, Interest-bearing Deposits in Banks (Details)	12 Months Ended
Dec. 31, 2023
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.

No definition available.

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