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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	$ 6,504	$ 6,177	$ 6,190	$ 8,798
Interest Income Recognized	12	16	43	47
Commercial real estate \| Owner occupied
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	2,126	1,569	1,950	1,372
Interest Income Recognized	0	1	1	2
Commercial real estate \| Non-owner occupied
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	150	0	60	2,395
Interest Income Recognized	0	0	0	0
Commercial real estate \| Multi-family
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	110	144	118	152
Interest Income Recognized	0	0	0	0
Commercial real estate \| Non-owner occupied residential
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	173	336	246	355
Interest Income Recognized	0	0	0	0
Acquisition and development \| 1-4 family residential construction
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	0	201	0	235
Interest Income Recognized	0	0	0	0
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	765	316	469	330
Interest Income Recognized	0	0	0	0
Residential mortgage \| First lien
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	2,392	2,900	2,574	3,312
Interest Income Recognized	12	15	41	44
Residential mortgage \| Home equity - term
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	12	18	13	20
Interest Income Recognized	0	0	0	0
Residential mortgage \| Home equity - lines of credit
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	768	692	752	621
Interest Income Recognized	0	0	1	1
Installment and other loans
Financing Receivable, Impaired [Line Items]
Average Impaired Balance	8	1	8	6
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=118936363&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=118936363&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_OneToFourFamilyResidentialConstructionMember
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: