Loans and Leases and the Allowance for Credit Losses - Schedule of Non-Accrual Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	$ 12,979	$ 13,261
Non-Accrual Loans without a Related ACL	3,112	3,382
Total Non-Accrual Loans	16,091	16,643
Commercial
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	2,534	3,695
Non-Accrual Loans without a Related ACL	3,112	3,382
Total Non-Accrual Loans	5,646	7,077
Commercial \| Commercial Mortgage
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	0	0
Non-Accrual Loans without a Related ACL	2,195	2,450
Total Non-Accrual Loans	2,195	2,450
Commercial \| Commercial and Industrial
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	2,534	3,695
Non-Accrual Loans without a Related ACL	917	932
Total Non-Accrual Loans	3,451	4,627
Consumer
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	10,445	9,566
Non-Accrual Loans without a Related ACL	0	0
Total Non-Accrual Loans	10,445	9,566
Consumer \| Residential Mortgage
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	4,686	5,052
Non-Accrual Loans without a Related ACL	0	0
Total Non-Accrual Loans	4,686	5,052
Consumer \| Home Equity
Financing Receivable Nonaccrual Status [Line Items]
Non-Accrual Loans with a Related ACL	5,759	4,514
Non-Accrual Loans without a Related ACL	0	0
Total Non-Accrual Loans	$ 5,759	$ 4,514

Financing Receivable, Excluding Accrued Interest, Nonaccrual, with Allowance

No definition available.

Name:	boh_FinancingReceivableExcludingAccruedInterestNonaccrualWithAllowance
Namespace Prefix:	boh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrualNoAllowance
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=boh_CommercialAndIndustrialMember
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:

- Details

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

- Details

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