Represents the value of assets secured for the standby letters of credit.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Commitments Contingencies and Guarantees.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
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- Definition

Current loans serviced for third parties as percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	boh_
Data Type:	num:percentItemType
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- Definition

Number of Mortgage Loans Repurchased

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Number of Mortgage Loans Repurchased, Pending

+ References

No definition available.

+ Details

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- Definition

Number of Mortgage Loans Repurchased due to Loan Servicing Activities

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Number of Mortgage Loans Repurchased due to Loan Servicing Activities, Pending

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Represents the remaining term of standby and commercial letters of credit.

+ References

No definition available.

+ Details

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Namespace Prefix:	boh_
Data Type:	xbrli:durationItemType
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- Definition

Cash Flows between a transferor and a transferee attributable to purchases of previously transferred financial assets (or its underlying collateral) related to a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(3)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107207-111719

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107314-111719

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount awarded from other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageMember
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Balance Type:
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- Details

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- Details

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Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
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Commitments, Contingencies, and Guarantees - Additional Information (Details) $ in Millions		12 Months Ended
	Dec. 06, 2019 USD ($)	Dec. 31, 2020 USD ($) Loan	Dec. 31, 2019 USD ($)
Residential Mortgage
Representations and Warranties [Line Items]
Continuing involvement with transferred financial assets, principal amount outstanding		$ 2,500.0
Number of mortgage loans repurchased \| Loan		40
Unpaid principal balance of repurchased mortgage loan		$ 13.4
Number of mortgage loans repurchased, pending \| Loan		0
Number of mortgage loans repurchased due to loan servicing activities \| Loan		0
Number of mortgage loans repurchased due to loan servicing activities, pending \| Loan		0
Current residential mortgage loans serviced for third parties as percentage of total		99.00%
Class Settlement \| Settled Litigation
Representations and Warranties [Line Items]
Litigation settlement amount	$ 8.0
Litigation settlement, amount awarded from other party		$ 8.0	$ 2.0
Standby Letters of Credit
Representations and Warranties [Line Items]
Assets secured for standby letters of credit		$ 73.3
Standby and Commercial Letters of Credit \| Minimum [Member]
Representations and Warranties [Line Items]
Standby and commercial letters of credit remaining term		1 month
Standby and Commercial Letters of Credit \| Maximum
Representations and Warranties [Line Items]
Standby and commercial letters of credit remaining term		14 months