Bank segment (HEI only) - Loan Modifications (Details)	12 Months Ended
Dec. 31, 2020 USD ($) contract	Dec. 31, 2019 USD ($) contract	Dec. 31, 2018 USD ($) contract
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	68	25	70
Pre-modification outstanding recorded investment	$ 26,991,000	$ 8,821,000	$ 10,728,000
Post-modification outstanding recorded investment	$ 5,379,000	$ 680,000	$ 815,000
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	2
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 327,000
Commitments to borrowers whose loan terms are impaired or modified under troubled debt restructuring	0	0
Consumer mortgage loans collateralized by residential real estate property in foreclosure process	$ 3,800,000	$ 3,500,000
Residential 1-4 family
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	1	11	3
Pre-modification outstanding recorded investment	$ 144,000	$ 1,770,000	$ 566,000
Post-modification outstanding recorded investment	$ 6,000	$ 190,000	$ 26,000
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Commercial real estate
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	6	0	0
Pre-modification outstanding recorded investment	$ 20,714,000	$ 0	$ 0
Post-modification outstanding recorded investment	$ 4,439,000	$ 0	$ 0
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Home equity line of credit
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	3	3	53
Pre-modification outstanding recorded investment	$ 85,000	$ 442,000	$ 6,659,000
Post-modification outstanding recorded investment	$ 11,000	$ 73,000	$ 578,000
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	1
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 81,000
Residential land
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	4	3	2
Pre-modification outstanding recorded investment	$ 668,000	$ 1,086,000	$ 1,338,000
Post-modification outstanding recorded investment	$ 54,000	$ 0	$ 0
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Commercial construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	$ 0	$ 0	$ 0
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Residential construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	$ 0	$ 0	$ 0
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Commercial
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	54	8	12
Pre-modification outstanding recorded investment	$ 5,380,000	$ 5,523,000	$ 2,165,000
Post-modification outstanding recorded investment	$ 869,000	$ 417,000	$ 211,000
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	1
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 246,000
Consumer
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	$ 0	$ 0	$ 0
Troubled debt restructuring that subsequently defaulted, number of contracts \| contract	0	0	0
Troubled debt restructuring that subsequently defaulted, recorded investment	$ 0	$ 0	$ 0
Troubled debt restructurings real estate loans
Loan modifications determined to be troubled debt restructurings
Minimum period of payment default of loans determined to be TDRs	90 days	90 days	90 days

Represents the commitments to borrowers whose loan terms are impaired or modified under troubled debt restructuring.

No definition available.

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- Definition

Financial Receivables, Loans Collateralized by Real Estate in Foreclosure

+ References

No definition available.

+ Details

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- Definition

Represents the minimum period of payment default of loans determined to be troubled debt restructurings.

+ References

No definition available.

+ Details

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- Definition

The amount of the outstanding recorded investment in financial receivables after the financial receivables being modified as troubled debt restructurings.

+ References

No definition available.

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- Definition

The amount of the outstanding recorded investment in financial receivables prior to the financial receivables being modified as troubled debt restructurings.

+ References

No definition available.

+ Details

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- 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

No definition available.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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- Definition

Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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- Definition

Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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