Affordable Housing Projects Tax Credit Partnerships - Tax Credits and Other Tax Benefits Recognized and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Effective Yield Method
Tax Credits and Other Tax Benefits Recognized	$ 1,137	$ 1,457	$ 3,411	$ 4,372
Amortization Expense in Provision for Income Taxes	1,119	1,333	3,358	3,998
Proportional Amortization Method
Tax Credits and Other Tax Benefits Recognized	6,210	3,696	18,631	14,572
Amortization Expense in Provision for Income Taxes	$ 5,348	$ 3,203	$ 16,044	$ 12,630

Affordable Housing Tax Credits, Proportional Amortization Method.

No definition available.

Name:	boh_AffordableHousingTaxCreditProportionalAmortizationMethod
Namespace Prefix:	boh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Effective yield Methods

+ References

No definition available.

+ Details

Name:	boh_EffectiveYieldMethodsAbstract
Namespace Prefix:	boh_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Proportional amortization methods.

+ References

No definition available.

+ Details

Name:	boh_ProportionalAmortizationMethodsAbstract
Namespace Prefix:	boh_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Proportional Amortization Method, Qualified Affordable Housing Project Investments, Amortization

+ References

No definition available.

+ Details

Name:	boh_ProportionalAmortizationMethodsQualifiedAffordableHousingProjectInvestmentsAmortization
Namespace Prefix:	boh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, before amortization expense, of income tax credit and other tax benefit generated by investment under tax credit program elected to be accounted for using proportional amortization method. Includes, but is not limited to, investment under tax credit program not meeting condition for accounting under proportional amortization method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 323
-SubTopic 740
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478156/323-740-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 323
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A

+ Details

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

- Definition

Amount of amortization expense for investment that generates income tax credit and other income tax benefit under tax credit program accounted for using proportional amortization method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 740
-SubTopic 323
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478156/740-323-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 323
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478156/740-323-50-1A

+ Details

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