Loans and Leases and the Allowance for Loan and Lease Losses (Troubled Debt Restructuring's that Defaulted During the Period) (Details 7) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017 USD ($) contract	Jun. 30, 2016 USD ($) contract	Jun. 30, 2017 USD ($) contract	Jun. 30, 2016 USD ($) contract
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract	30	13	54	30
Recorded Investment (as of period ended), TDRs that Defaulted \| $	$ 404	$ 134	$ 694	$ 1,417
Minimum
Information related to loans modified as a TDR
Default Period Past Due Following Modification of Loans in TDR (in days)			60 days
Commercial
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract			1	0
Recorded Investment (as of period ended), TDRs that Defaulted \| $			$ 49	$ 0
Commercial \| Commercial and Industrial
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract			1	0
Recorded Investment (as of period ended), TDRs that Defaulted \| $			$ 49	$ 0
Consumer
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract	30	13	53	30
Recorded Investment (as of period ended), TDRs that Defaulted \| $	$ 404	$ 134	$ 645	$ 1,417
Consumer \| Residential Mortgage
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract	0	1	0	3
Recorded Investment (as of period ended), TDRs that Defaulted \| $	$ 0	$ 43	$ 0	$ 1,056
Consumer \| Home Equity
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract			0	1
Recorded Investment (as of period ended), TDRs that Defaulted \| $			$ 0	$ 162
Consumer \| Automobile
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract	12	3	17	4
Recorded Investment (as of period ended), TDRs that Defaulted \| $	$ 267	$ 21	$ 390	$ 57
Consumer \| Other
Information related to loans modified as a TDR
Number of Contracts, TDRs that Defaulted \| contract	18	9	36	22
Recorded Investment (as of period ended), TDRs that Defaulted \| $	$ 137	$ 70	$ 255	$ 142

Represents the number of days past due following modification of loans in a troubled debt restructuring, when a loan is considered to be in default.

No definition available.

+ Details

Name:	boh_FinancingReceivableModificationsMadeDefaultPeriod
Namespace Prefix:	boh_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
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:

- Details

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

- Details

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