Fair Value of Assets and Liabilities (Details 2) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	$ 10,298	$ 15,144	$ 9,894	$ 15,152
Realized and Unrealized Net Gains (Losses): Included in Net Income	1,037	3,833	2,012	5,652
Transfers to Loans Held for Sale	(2,051)	(3,130)	(2,622)	(4,957)
Balance at the end of the period	9,284	15,847	9,284	15,847
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	(121)	1,453	(55)	1,361
Mortgage Servicing Rights.
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	9,692	14,807	10,226	15,332
Realized and Unrealized Net Gains (Losses): Included in Net Income	(840)	(967)	(1,374)	(1,492)
Balance at the end of the period	8,852	13,840	8,852	13,840
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	(553)	(554)	(487)	(646)
Net Derivative Assets and Liabilities
Changes in Level 3 assets measured at fair value on a recurring basis
Balance at the beginning of the period	606	337	(332)	(180)
Realized and Unrealized Net Gains (Losses): Included in Net Income	1,877	4,800	3,386	7,144
Transfers to Loans Held for Sale	(2,051)	(3,130)	(2,622)	(4,957)
Balance at the end of the period	432	2,007	432	2,007
Total Unrealized Net Gains (Losses) Included in Net Income Related to Assets Still Held as of the end of the period	$ 432	$ 2,007	$ 432	$ 2,007

This element represents the total unrealized net gains included in net income related to assets still held as of the balance sheet date.

Name:	boh_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsRelatedToAssetsStillHeld
Namespace Prefix:	boh
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents transfers to loans held for sale which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ Details

Name:	boh_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersToLoansHeldforSale
Namespace Prefix:	boh
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph c(1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant