Bank segment (HEI only) - Mortgage Servicing Rights and Valuation Allowance Roll Forward (Details) - American Savings Bank (ASB) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Mortgage servicing rights
Beginning balance	$ 9,047
Ending balance	8,169	$ 9,047
Allowance for mortgage-servicing assets – bank
Mortgage servicing rights
Beginning balance	9,047	9,950	$ 10,280
Amount capitalized	423	1,130	3,404
Amortization	(1,301)	(2,033)	(3,734)
Sale of mortgage servicing rights	0	0	0
Other-than-temporary impairment	0	0	0
Ending balance	8,169	9,047	9,950
Valuation allowance for mortgage servicing rights
Beginning balance	0	0	260
Provision	0	0	(260)
Other-than-temporary impairment	0	0	0
Ending balance	0	0	0
Net carrying amount	8,169	$ 9,047	$ 9,950
Estimated Aggregate Amortization Expenses of Mortgage Servicing Rights
2024	1,000
2025	900
2026	800
2027	800
2028	$ 700

Estimated Aggregate Amortization Expenses of Mortgage Servicing Rights [Abstract]

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Mortgage Servicing Rights [Roll Forward]

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of amortization for assets, excluding financial assets and goodwill, lacking physical substance with finite life expected to be recognized in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of other-than-temporary impairment (OTTI) applied to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount conveyed to unrelated parties of contract to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of increase (decrease) in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from expenses (recoveries) recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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