Investment Securities (Gains and losses by category) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2016	Dec. 31, 2015
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	$ 17,351	$ 180,338
Available for sale - Amortized cost - more than 12 month	42,259	121,141
Total Available for Sale Amortization cost	59,610	301,479
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	55	1,869
Available for sale - Unrealized Loss - more than 12 month	927	6,480
Total Available for Sale Unrealized Loss	982	8,349
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	17,296	178,469
Available-for-sale, Fair Value - more than 12 month	41,332	114,661
Total Available for Sale Fair Value	58,628	293,130
Continuous Unrealized Loss Position Amortized Cost [Abstract]
Held to Maturity - Amortized cost - less than 12 month	21,240	493,519
Held to Maturity - Amortized Cost	21,240	493,519
Held To Maturity Securities, Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Held to Maturity- Unrealized Loss - less than 12 month	18
Held to Maturity- Unrealized Loss - more than 12 month		5,936
Held to Maturity- Unrealized Loss	18	5,936
Held To Maturity Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Held-to-Maturity - Fair Value - less than 12 Month	21,222	487,583
Held to Maturity - Fair Value	21,222	487,583
Investment Securities Continuous Unrealized Loss Position [Abstract]
Investment Securities - Amortized Cost - less than 12 month	38,591	673,857
Investment Securities - Amortized Cost - more than 12 month	42,259	121,141
Investment Securities - Amortized Cost	80,850	794,998
Investment Securities - Unrealized Position - less than 12 month	73	7,805
Investment Securities - Unrealized Position - more than 12 month	927	6,480
Investment Securities - Unrealized Loss	1,000	14,285
Investment Securities - Fair Value - less than 12 month	38,518	666,052
Investment Securities - Fair Value - more than 12 month	41,332	114,661
Investment Securities - Fair Value	79,850	780,713
CMO's issued by us government sponsored agencies at loss
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	13,181	25,736
Available for sale - Amortized cost - more than 12 month	37,579	103,340
Total Available for Sale Amortization cost	50,760	129,076
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	50	331
Available for sale - Unrealized Loss - more than 12 month	320	2,410
Total Available for Sale Unrealized Loss	370	2,741
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	13,131	25,405
Available-for-sale, Fair Value - more than 12 month	37,259	100,930
Total Available for Sale Fair Value	50,390	126,335
Obligation of Puerto Rico Government and public instrumentalities at loss
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - more than 12 month	4,680	17,801
Total Available for Sale Amortization cost	4,680	17,801
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - more than 12 month	607	4,070
Total Available for Sale Unrealized Loss	607	4,070
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available-for-sale, Fair Value - more than 12 month	4,073	13,731
Total Available for Sale Fair Value	4,073	13,731
FNMA and FHLMC [Member]
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month		149,480
Total Available for Sale Amortization cost		149,480
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month		1,509
Total Available for Sale Unrealized Loss		1,509
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month		147,971
Total Available for Sale Fair Value		147,971
Continuous Unrealized Loss Position Amortized Cost [Abstract]
Held to Maturity - Amortized cost - less than 12 month	21,240	468,487
Held to Maturity - Amortized Cost	21,240	468,487
Held To Maturity Securities, Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Held to Maturity- Unrealized Loss - less than 12 month	18
Held to Maturity- Unrealized Loss - more than 12 month		5,865
Held to Maturity- Unrealized Loss	18	5,865
Held To Maturity Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Held-to-Maturity - Fair Value - less than 12 Month	21,222	462,622
Held to Maturity - Fair Value	21,222	462,622
Obligation of US Government sponsored agencies at loss [Member]
Available For Sale Securities Continuous Unrealized Loss Position Amortized Cost [Abstract]
Available for sale - Amortized cost - less than 12 month	4,170	5,122
Total Available for Sale Amortization cost	4,170	5,122
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Available for sale - Unrealized Loss - less than 12 month	5	29
Total Available for Sale Unrealized Loss	5	29
Available For Sale Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Available for sale - Fair Value - less than 12 month	4,165	5,093
Total Available for Sale Fair Value	$ 4,165
US Treasury Securities at loss
Continuous Unrealized Loss Position Amortized Cost [Abstract]
Held to Maturity - Amortized cost - less than 12 month		25,032
Held to Maturity - Amortized Cost		25,032
Held To Maturity Securities, Continuous Unrealized Loss Position Aggregate Losses [Abstract]
Held to Maturity- Unrealized Loss - more than 12 month		71
Held to Maturity- Unrealized Loss		71
Held To Maturity Securities Continuous Unrealized Loss Position Fair Value [Abstract]
Held-to-Maturity - Fair Value - less than 12 Month		24,961
Held to Maturity - Fair Value		$ 24,961

Amortized cost of investments in available-for-sale securities that have been in a loss position.

No definition available.

Name:	ofg_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	ofg_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAmortizedCostAbstract
Namespace Prefix:	ofg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost of investments in available-for-sale securities that have been in a loss position for less than twelve months.

+ References

No definition available.

+ Details

Name:	ofg_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost of investments in available-for-sale securities that have been in a loss position for more than twelve months.

+ References

No definition available.

+ Details

Name:	ofg_AvailableforsalesecuritiesContinuousUnrealizedLossPosition12MonthsorLongerAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	ofg_ContinuousUnrealizedLossPositionAmortizedCostAbstract1Abstract
Namespace Prefix:	ofg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost of investments in held-to-maturity securities that have been in a loss position for less than twelve months.

+ References

No definition available.

+ Details

Name:	ofg_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLessAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Held to maturity securities continuous unrealized loss position, amortized cost.

+ References

No definition available.

+ Details

Name:	ofg_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAbstract
Namespace Prefix:	ofg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate losses of investments in securities that have been in a loss position.

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAggregateLosses
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Investment Securities Continuous Unrealized Loss Position Aggregate Losses Less Than Twelve Month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAggregateLossesLessThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Investment Securities Continuous Unrealized Loss Position Aggregate Losses More Than Twelve Month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAggregateLossesMoreThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost of investments in securities that have been in a loss position.

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAmortizedCost
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Investment Securities Continuous Unrealized Loss Position Amortized Cost More than Twelve month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionAmortizedCostMoreThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair Value of investments in securities that have been in a loss position.

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Investment Securities Continuous Unrealized Loss Position Fair Value Less Than Twelve Month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionFairValueLessThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Investment Securities Continuous Unrealized Loss Position Fair Value More Than Twelve Month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentSecuritiesContinuousUnrealizedLossPositionFairValueMoreThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Investment Securities Continuous Unrealized Loss Position Amortized Cost Less than Twelve month

+ References

No definition available.

+ Details

Name:	ofg_InvestmentsecuritiesContinuousUnrealizedLossPositionAmortizedCostLessThanTwelveMonth
Namespace Prefix:	ofg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized loss on securities classified as available-for-sale that have been in a loss position for twelve months or longer.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of unrealized loss on securities classified as available-for-sale.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities.

+ References

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of unrealized loss on investments in available-for-sale securities that have been in a loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item represents the aggregate fair value of investments in debt and equity securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

This item represents the fair value of securities categorized as held-to-maturity which are in an unrealized loss position.

+ References

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

This item represents the fair value of securities categorized as held-to-maturity that have been in a continuous unrealized loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized loss on investments in held-to-maturity securities that have been in a loss position for twelve months or longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

+ Details

Name:	us-gaap_HeldtomaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of unrealized loss on investments in held-to-maturity securities.

+ References

+ Details

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

- Definition

Amount of unrealized loss before deducting unrealized gain on investments in held-to-maturity securities that have been in a loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

+ Details

Name:	us-gaap_HeldtomaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	invest_InvestmentSecuritiesClassAxis=us-gaap_CollateralizedMortgageObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSecuritiesClassAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSecuritiesClassAxis=ofg_FnmaAndFhlmcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSecuritiesClassAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSecuritiesClassAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: