Fair Value of Assets and Liabilities (FV option) (Details 5) - Residential mortgage loans held for sale - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Fair Value Option
Aggregate Fair Value	$ 3,222	$ 5,136
Aggregate Unpaid Principal	3,009	4,740
Aggregate Fair Value Less Aggregate Unpaid Principal	$ 213	$ 396

Represents the aggregate unpaid principal balance of loans held for sale for which the fair value option was elected.

No definition available.

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

- Definition

This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of loans and long-term receivables (other than securities categorized as trading, available-for-sale or held-to-maturity) that have contractual principal amounts and for which the fair value option has been elected.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 28

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

+ Details

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

- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_EligibleItemOrGroupForFairValueOptionAxis=boh_ResidentialMortgageHeldForSaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: