Loans Receivable (Interest Income Recognized in loans individually evaluated for impairment) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Loan [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Total Interest Income	$ 1,116	$ 1,557	$ 3,272	$ 3,647
Impaired Financing Receivable Average Recorded Investment [Abstract]
Total Average Recorded Investment	152,614	147,756	153,845	147,578
Originated Loans [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Total Interest Income	1,116	1,557	3,272	3,647
Impaired Financing Receivable Average Recorded Investment [Abstract]
Total Average Recorded Investment	151,867	147,005	153,098	146,768
Acquired loans accounted for under ASC 310-20 [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Total Interest Income	0	0	0	0
Impaired Financing Receivable Average Recorded Investment [Abstract]
Total Average Recorded Investment	0	0	0	0
Commercial Loan [Member] \| Originated Loans [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Impaired Financing Receivable With Related Allowance Interest Income Accrual Method	150	306	432	612
Impaired Financing Receivable With No Related Allowance Interest Income Accrual Method	271	675	812	1,350
Impaired Financing Receivable Average Recorded Investment [Abstract]
Impaired Financing Receivable With Related Allowance Average Recorded Investment	35,765	24,178	44,691	17,298
Impaired Financing Receivable With No Related Allowance Average Recorded Investment	31,315	36,133	23,736	41,519
Commercial Loan [Member] \| Acquired loans accounted for under ASC 310-20 [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Impaired Financing Receivable With Related Allowance Interest Income Accrual Method	0	0	0	0
Impaired Financing Receivable With No Related Allowance Interest Income Accrual Method	0	0	0	0
Impaired Financing Receivable Average Recorded Investment [Abstract]
Impaired Financing Receivable With Related Allowance Average Recorded Investment	747	751	747	810
Impaired Financing Receivable With No Related Allowance Average Recorded Investment	0	0	0	0
Troubled Debt Restructuring [Member] \| Originated Loans [Member]
Impaired Financing Receivable Interest Income Accrual Method [Abstract]
Impaired Financing Receivable With Related Allowance Interest Income Accrual Method	695	576	2,028	1,685
Impaired Financing Receivable Average Recorded Investment [Abstract]
Impaired Financing Receivable With Related Allowance Average Recorded Investment	$ 84,787	$ 86,694	$ 84,671	$ 87,951

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

+ Details

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

- References

No definition available.

+ Details

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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

- References

No definition available.

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

+ References

+ Details

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

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ofg_LoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ofg_OriginatedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ofg_AccountedForUnderAsc31020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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