Mortgage Servicing Rights (Details 4) (Mortgage Servicing Rights, USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Mortgage Servicing Rights
Constant Prepayment Rate
Decrease in fair value from 25 basis points ("bps") adverse change	$ (333)	$ (295)
Decrease in fair value from 50 bps adverse change	(657)	(582)
Discount Rate
Decrease in fair value from 25 bps adverse change	(386)	(331)
Decrease in fair value from 50 bps adverse change	$ (760)	$ (652)

The hypothetical financial impact of 25 basis points' adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

No definition available.

Name:	boh_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactFrom25BasisPointsAdverseChangeInPrepaymentSpeed
Namespace Prefix:	boh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant