LOANS AND ALLOWANCE FOR LOAN LOSSES - Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Activity in allowance for loan losses
Balance, beginning of period	$ 13,437	$ 12,751	$ 12,796	$ 12,775
Provision for loan losses	200	100	600	200
Charge-offs	(159)	(135)	(363)	(342)
Recoveries	334	55	779	138
Balance, end of period	13,812	12,771	13,812	12,771
Unallocated
Activity in allowance for loan losses
Balance, beginning of period	585	470	475	414
Provision for loan losses	(75)	51	35	107
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	510	521	510	521
Commercial
Activity in allowance for loan losses
Balance, beginning of period	9,078	8,764	8,710	9,238
Provision for loan losses	174	(13)	211	(424)
Charge-offs	(17)	(30)	(17)	(130)
Recoveries	201	2	532	39
Balance, end of period	9,436	8,723	9,436	8,723
Commercial \| Commercial Real Estate
Activity in allowance for loan losses
Balance, beginning of period	6,680	6,777	6,763	7,530
Provision for loan losses	194	(102)	(217)	(840)
Charge-offs	(17)	0	(17)	(45)
Recoveries	200	0	528	30
Balance, end of period	7,057	6,675	7,057	6,675
Commercial \| Acquisition and Development
Activity in allowance for loan losses
Balance, beginning of period	720	579	417	580
Provision for loan losses	19	(90)	319	(93)
Charge-offs	0	0	0	0
Recoveries	0	1	3	3
Balance, end of period	739	490	739	490
Commercial \| Commercial and Industrial
Activity in allowance for loan losses
Balance, beginning of period	1,598	1,291	1,446	1,074
Provision for loan losses	(38)	191	114	458
Charge-offs	0	(30)	0	(85)
Recoveries	1	1	1	6
Balance, end of period	1,561	1,453	1,561	1,453
Commercial \| Municipal
Activity in allowance for loan losses
Balance, beginning of period	80	117	84	54
Provision for loan losses	(1)	(12)	(5)	51
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	79	105	79	105
Consumer
Activity in allowance for loan losses
Balance, beginning of period	3,774	3,517	3,611	3,123
Provision for loan losses	101	62	354	517
Charge-offs	(142)	(105)	(346)	(212)
Recoveries	133	53	247	99
Balance, end of period	3,866	3,527	3,866	3,527
Consumer \| Residential Mortgage
Activity in allowance for loan losses
Balance, beginning of period	3,544	3,386	3,400	2,979
Provision for loan losses	(45)	(12)	157	429
Charge-offs	(62)	(54)	(148)	(105)
Recoveries	102	41	130	58
Balance, end of period	3,539	3,361	3,539	3,361
Consumer \| Installment and Other
Activity in allowance for loan losses
Balance, beginning of period	230	131	211	144
Provision for loan losses	146	74	197	88
Charge-offs	(80)	(51)	(198)	(107)
Recoveries	31	12	117	41
Balance, end of period	$ 327	$ 166	$ 327	$ 166

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of expense related to estimated loss from loan and lease transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

+ Details

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

- Details

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

- Details

Name:	us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis=us-gaap_CommercialBorrowerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_ClassOfFinancingReceivableTypeOfBorrowerAxis=us-gaap_ConsumerBorrowerMember
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_FinancingReceivablePortfolioSegmentAxis=orrf_InstallmentandOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: