Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year

No definition available.

Name:	opbk_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract
Namespace Prefix:	opbk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Revolving, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff

+ References

No definition available.

+ Details

Name:	opbk_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	opbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after allowance for credit loss, of accrued interest on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3A
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267960-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL120267845-210446

+ Details

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

- Definition

Indicates line item in statement of financial position that includes accrued interest, after allowance for credit loss, on financing receivable.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ Details

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

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI https://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919232-210447

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_DoubtfulMember
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=opbk_SBARealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

Loans and Allowance for Credit Losses on Loans - Schedule of Credit Risk Ratings by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Financing Receivable Recorded Investment [Line Items]
2023	$ 52,315
2022	618,291
2021	294,577
2020	159,976
2019	197,830
Prior	309,803
Revolving Loans	59,693
Total	1,692,485		$ 1,678,292
2023	0
2022	0
2021	11
2020	0
2019	91
Prior	14
Revolving Loans	0
Total	116	$ 14
Current period charge-offs
2023	0
2022	0
2021	11
2020	0
2019	91
Prior	14
Revolving Loans	0
Total	$ 116	14
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Accrued interest receivable		Accrued interest receivable
Accrued interest receivable	$ 6,400		$ 6,400
Pass
Financing Receivable Recorded Investment [Line Items]
2023	52,315
2022	618,291
2021	292,735
2020	159,185
2019	196,894
Prior	305,992
Revolving Loans	59,693
Total	1,685,105		1,674,422
Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	936
Prior	1,681
Revolving Loans	0
Total	2,617		563
Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	1,842
2020	791
2019	0
Prior	1,785
Revolving Loans	0
Total	4,418		3,031
Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	345
Revolving Loans	0
Total	345		276
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
2023	17,774
2022	216,444
2021	150,672
2020	101,254
2019	147,925
Prior	188,362
Revolving Loans	11,184
Total	833,615		842,208
2023	0
2022	0
2021	0
2020	0
2019	91
Prior	0
Revolving Loans	0
Total	91	0
Current period charge-offs
2023	0
2022	0
2021	0
2020	0
2019	91
Prior	0
Revolving Loans	0
Total	91	0
Commercial Real Estate \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	17,774
2022	216,444
2021	150,672
2020	101,254
2019	147,925
Prior	187,802
Revolving Loans	11,184
Total	833,055		841,645
Commercial Real Estate \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	560
Revolving Loans	0
Total	560		563
Commercial Real Estate \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Commercial Real Estate \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
SBA—real estate
Financing Receivable Recorded Investment [Line Items]
2023	2,686
2022	49,259
2021	33,531
2020	29,056
2019	33,264
Prior	77,923
Revolving Loans	0
Total	225,719		221,340
2023	0
2022	0
2021	11
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	11	14
Current period charge-offs
2023	0
2022	0
2021	11
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	11	14
SBA—real estate \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	2,686
2022	49,259
2021	32,031
2020	29,056
2019	32,328
Prior	75,815
Revolving Loans	0
Total	221,175		220,348
SBA—real estate \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	936
Prior	1,121
Revolving Loans	0
Total	2,057		0
SBA—real estate \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	1,500
2020	0
2019	0
Prior	987
Revolving Loans	0
Total	2,487		992
SBA—real estate \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
SBA—non-real estate
Financing Receivable Recorded Investment [Line Items]
2023	1,235
2022	2,958
2021	539
2020	2,146
2019	1,070
Prior	5,327
Revolving Loans	0
Total	13,275		13,377
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	14
Revolving Loans	0
Total	14	0
Current period charge-offs
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	14
Revolving Loans	0
Total	14	0
SBA—non-real estate \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	1,235
2022	2,958
2021	539
2020	2,146
2019	1,070
Prior	4,586
Revolving Loans	0
Total	12,534		12,621
SBA—non-real estate \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
SBA—non-real estate \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	396
Revolving Loans	0
Total	396		480
SBA—non-real estate \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	345
Revolving Loans	0
Total	345		276
C&I
Financing Receivable Recorded Investment [Line Items]
2023	4,054
2022	24,304
2021	26,764
2020	6,533
2019	5,564
Prior	3,111
Revolving Loans	47,511
Total	117,841		116,951
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	0
Current period charge-offs
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	0
C&I \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	4,054
2022	24,304
2021	26,764
2020	6,533
2019	5,564
Prior	2,841
Revolving Loans	47,511
Total	117,571		116,672
C&I \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
C&I \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	270
Revolving Loans	0
Total	270		279
C&I \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Home mortgage
Financing Receivable Recorded Investment [Line Items]
2023	26,513
2022	325,326
2021	83,071
2020	20,987
2019	9,858
Prior	34,880
Revolving Loans	0
Total	500,635		482,949
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	0
Current period charge-offs
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	0
Home mortgage \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	26,513
2022	325,326
2021	82,729
2020	20,196
2019	9,858
Prior	34,748
Revolving Loans	0
Total	499,370		481,669
Home mortgage \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Home mortgage \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	342
2020	791
2019	0
Prior	132
Revolving Loans	0
Total	1,265		1,280
Home mortgage \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Consumer
Financing Receivable Recorded Investment [Line Items]
2023	53
2022	0
2021	0
2020	0
2019	149
Prior	200
Revolving Loans	998
Total	1,400		1,467
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	0
Current period charge-offs
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0	$ 0
Consumer \| Pass
Financing Receivable Recorded Investment [Line Items]
2023	53
2022	0
2021	0
2020	0
2019	149
Prior	200
Revolving Loans	998
Total	1,400		1,467
Consumer \| Special mention
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Consumer \| Substandard
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	0		0
Consumer \| Doubtful
Financing Receivable Recorded Investment [Line Items]
2023	0
2022	0
2021	0
2020	0
2019	0
Prior	0
Revolving Loans	0
Total	$ 0		$ 0