DERIVATIVE FINANCIAL INSTRUMENTS - Summary of Effect of Derivative Financial Instruments on OCI and Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Net Loss Recognized in OCI on Derivative	$ (2,747)	$ (67)	$ (1,065)	$ (1,441)
Amount of Gain Reclassified from AOCI into Income	191	0	228	0
Amount of Gain (Loss) Recognized in Income	597	52	691	(343)
Interest rate products
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Net Loss Recognized in OCI on Derivative	(2,938)	(67)	(1,293)	(1,441)
Interest rate products \| Location, Statement of Income, Balance [Axis]: us-gaap:InterestExpenseOperating
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain Reclassified from AOCI into Income	191	0	228	0
Interest rate products \| Location, Statement of Income, Balance [Axis]: us-gaap:OtherNoninterestExpense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Income	606	12	652	(384)
Interest rate swaps \| Location, Statement of Income, Balance [Axis]: us-gaap:InterestAndFeeIncomeLoansAndLeases \| Interest rate swaps - commercial loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Income	0	0	0	(1)
Risk participation agreements \| Location, Statement of Income, Balance [Axis]: us-gaap:OtherNoninterestExpense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Income	12	(1)	16	0
Interest rate lock commitments with customers \| Location, Statement of Income, Balance [Axis]: orrf:FeesAndCommissionsMortgageBankingAndServicesNet
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Income	(68)	34	(38)	69
Forward sale commitments \| Location, Statement of Income, Balance [Axis]: orrf:FeesAndCommissionsMortgageBankingAndServicesNet
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Recognized in Income	$ 47	$ 7	$ 61	$ (28)