No definition available.

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

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

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

+ Details

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

- References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fhb_CommercialAndIndustrialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=fhb_ConstructionPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_FinanceLeasesPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
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_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Allowance for Loan and Lease Losses - Disaggregation by Impairment Methodology (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Allowance for loan and lease losses:
Individually evaluated for impairment	$ 642		$ 1,092
Collectively evaluated for impairment	136,685		134,402
Total allowance for loan and lease losses	137,327	$ 136,883	135,494	$ 135,025	$ 136,360	$ 135,484
Loans and leases:
Individually evaluated for impairment	45,337		59,428
Collectively evaluated for impairment	12,104,374		11,460,950
Total loans and leases	12,149,711		11,520,378
Commercial Lending
Loans and leases:
Total loans and leases	6,586,061		6,213,147
Commercial and Industrial
Allowance for loan and lease losses:
Individually evaluated for impairment	4		380
Collectively evaluated for impairment	31,834		32,749
Total allowance for loan and lease losses	31,838	33,341	33,129	34,160	35,792	34,025
Loans and leases:
Individually evaluated for impairment	19,223		27,572
Collectively evaluated for impairment	3,171,014		3,212,028
Total loans and leases	3,190,237		3,239,600
Commercial Real Estate
Allowance for loan and lease losses:
Individually evaluated for impairment	7		7
Collectively evaluated for impairment	20,574		18,441
Total allowance for loan and lease losses	20,581	20,011	18,448	18,523	18,260	18,489
Loans and leases:
Individually evaluated for impairment	9,061		12,545
Collectively evaluated for impairment	2,616,627		2,330,950
Total loans and leases	2,625,688		2,343,495
Construction
Allowance for loan and lease losses:
Collectively evaluated for impairment	5,824		4,513
Total allowance for loan and lease losses	5,824	5,471	4,513	5,232	4,636	3,793
Loans and leases:
Collectively evaluated for impairment	598,763		450,012
Total loans and leases	598,763		450,012
Lease Financing
Allowance for loan and lease losses:
Collectively evaluated for impairment	820		847
Total allowance for loan and lease losses	820	857	847	725	780	888
Loans and leases:
Individually evaluated for impairment			153
Collectively evaluated for impairment	171,373		179,887
Total loans and leases	171,373		180,040
Residential
Allowance for loan and lease losses:
Individually evaluated for impairment	631		705
Collectively evaluated for impairment	44,246		42,731
Total allowance for loan and lease losses	44,877	44,374	43,436	46,042	46,452	46,099
Loans and leases:
Individually evaluated for impairment	17,053		19,158
Collectively evaluated for impairment	3,984,425		3,777,301
Total loans and leases	4,001,478		3,796,459
Consumer
Allowance for loan and lease losses:
Collectively evaluated for impairment	28,599		28,388
Total allowance for loan and lease losses	28,599	27,903	28,388	28,214	28,386	28,385
Loans and leases:
Collectively evaluated for impairment	1,562,172		1,510,772
Total loans and leases	1,562,172		1,510,772
Unallocated
Allowance for loan and lease losses:
Collectively evaluated for impairment	4,788		6,733
Total allowance for loan and lease losses	$ 4,788	$ 4,926	$ 6,733	$ 2,129	$ 2,054	$ 3,805