Represents the interest receivable written off by reversing interest income.

No definition available.

Name:	fhb_LoanAndLeaseLossesWriteOffsReversalOfInterestIncome
Namespace Prefix:	fhb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of interest income on impaired and nonperforming loans that is due to the change in present value attributable to the passage of time.

+ References

No definition available.

+ Details

Name:	fhb_LoansAndLeasesReceivableImpairedInterestIncomeRecognized
Namespace Prefix:	fhb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amortized cost of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- Definition

Amortized cost of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (3)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph a
-Subparagraph (2)
-Publisher SEC

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

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

- 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_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Allowance for Credit Losses - Nonaccrual Loans and Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases With No Allowance for Credit Losses	$ 4,435		$ 4,435		$ 6,515
Nonaccrual Loans and Leases	18,013		18,013		18,595
Interest income recognized on nonaccrual loans and leases	300	$ 200	500	$ 300
Accrued interest receivables written off, Interest income reversed		$ 300		$ 500
Commercial and Industrial
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases	1,084		1,084		970
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases With No Allowance for Credit Losses					2,685
Nonaccrual Loans and Leases	3,085		3,085		2,953
Construction
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases	447		447
Residential mortgage
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases With No Allowance for Credit Losses	3,285		3,285		2,667
Nonaccrual Loans and Leases	7,273		7,273		7,620
Home equity Line
Financing Receivable, Nonaccrual
Nonaccrual Loans and Leases With No Allowance for Credit Losses	1,150		1,150		1,163
Nonaccrual Loans and Leases	$ 6,124		$ 6,124		$ 7,052