Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

+ Details

Name:	us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

+ Details

Name:	us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The premium (cost) of a hedge, net of any cash received on settlement during the period.

+ References

No definition available.

+ Details

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

- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

+ References

+ Details

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

- Definition

Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

+ Details

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

- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

+ References

+ Details

Name:	us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_IncomeStatementLocationAxis=fhb_NetInterestIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=fhb_NoninterestIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Financial Instruments - Fair Value Hedges (Details) - Interest rate swaps - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Net gains and losses recognized in income related to derivatives in fair value hedging relationships
Net losses recognized on fair value hedges	$ (281)	$ (567)	$ (947)	$ (1,919)
Minimum \| Fair value hedges
Fair hedges carried
Fixed interest rate (as a percent)	2.59%		2.59%
Maximum \| Fair value hedges
Fair hedges carried
Fixed interest rate (as a percent)	5.70%		5.70%
Net interest income \| Fair value hedges
Net gains and losses recognized in income related to derivatives in fair value hedging relationships
Losses recorded	$ (279)	(547)	$ (973)	(2,011)
Noninterest income
Net gains and losses recognized in income related to derivatives in fair value hedging relationships
Recognized on derivatives	479	(977)	(1,039)	1,015
Recognized on hedged item	(481)	957	1,065	(923)
Net gains recognized on fair value hedges (ineffective portion)	(2)	$ (20)	26	$ 92
Derivatives designated as hedging instruments
Fair hedges carried
Notional amounts	202,394		202,394		$ 232,867
Derivatives designated as hedging instruments \| Fair value hedges
Fair hedges carried
Notional amounts	52,400		52,400		82,900
Positive fair value	0		0		0
Fair value losses	$ 3,500		$ 3,500		$ 2,400