LOANS AND ALLOWANCE FOR LOAN LOSSES - Average Recorded Investment in Impaired Loans and Related Interest Income (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	$ 10,864	$ 6,504	$ 11,514	$ 6,190
Interest Income Recognized	12	12	38	43
Commercial real estate \| Owner occupied
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	4,424	2,126	5,033	1,950
Interest Income Recognized	0	0	1	1
Commercial real estate \| Non-owner occupied
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	102	150	108	60
Interest Income Recognized	0	0	0	0
Commercial real estate \| Multi-family
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	141	110	259	118
Interest Income Recognized	0	0	0	0
Commercial real estate \| Non-owner occupied residential
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	433	173	422	246
Interest Income Recognized	0	0	0	0
Acquisition and development \| Commercial and land development
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	837	0	586	0
Interest Income Recognized	0	0	0	0
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	1,044	765	1,316	469
Interest Income Recognized	0	0	0	0
Residential mortgage \| First lien
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	3,209	2,392	3,050	2,574
Interest Income Recognized	12	12	36	41
Residential mortgage \| Home equity - term
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	12	12	12	13
Interest Income Recognized	0	0	0	0
Residential mortgage \| Home equity - lines of credit
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	645	768	699	752
Interest Income Recognized	0	0	1	1
Installment and other loans
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	17	8	29	8
Interest Income Recognized	$ 0	$ 0	$ 0	$ 0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

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

- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

+ Details

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

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_OwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_NonOwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_MultifamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_NonOwnerOccupiedResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=orrf_AcquisitionAndDevelopmentPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_CommercialAndLandDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=orrf_CommercialAndIndustrialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_FirstLienMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=orrf_HomeEquityTermMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=orrf_InstallmentandOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: