Bank segment - Mortgage Servicing Rights (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($) loan	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($) loan	Dec. 31, 2022 USD ($)
Servicing contracts
Prepayment rate:
25 basis points adverse rate change	$ (90)		$ (90)		$ (92)
50 basis points adverse rate change	(207)		(207)		(214)
Discount rate:
25 basis points adverse rate change	(206)		(206)		(182)
50 basis points adverse rate change	$ (407)		$ (407)		(361)
American Savings Bank (ASB)
Servicing Asset at Amortized Cost [Line Items]
Number of mortgage loans repurchased \| loan	0	1	0	1
Mortgage service fees	$ 900	$ 1,000	$ 2,700	$ 2,800
Mortgage servicing rights
Servicing asset - beginning balance			9,047
Servicing asset - ending balance	8,376		8,376
American Savings Bank (ASB) \| Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	21,500	12,100	36,100	126,400
Gain on sale of mortgage loans	300	200	700	1,600
American Savings Bank (ASB) \| Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	18,125		18,125		19,544
Accumulated amortization	(9,749)		(9,749)		(10,497)
Valuation allowance	0	0	0	0	0
Net carrying amount	8,376	9,351	8,376	9,351	9,047
Mortgage servicing rights
Servicing asset - beginning balance	8,495	9,696	9,047	9,950
Amount capitalized	184	117	319	1,040
Amortization	(303)	(462)	(990)	(1,639)
Other-than-temporary impairment	0	0	0	0
Servicing asset - ending balance	8,376	9,351	8,376	9,351
Valuation allowance for mortgage servicing rights
Valuation allowance, beginning balance	0	0	0	0
Provision	0	0	0	0
Other-than-temporary impairment	0	0	0	0
Valuation allowance, ending balance	0	$ 0	0	$ 0
Unpaid principal balance	$ 1,412,412		$ 1,412,412		$ 1,451,322
American Savings Bank (ASB) \| Servicing contracts \| Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0344		0.0344		0.0338
American Savings Bank (ASB) \| Servicing contracts \| Weighted average discount rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.1000		0.1000		0.1000
American Savings Bank (ASB) \| Servicing contracts \| Weighted average prepayment speed
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0558		0.0558		0.0656

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Fair Value Inputs, Prepayment Rate [Abstract]

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Fair Value Inputs, Unpaid Principal Balance, Asset

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Number Of Mortgage Loans Repurchased

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The hypothetical financial impact of a 25 basis point adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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Servicing Asset, Accumulated Amortization

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Servicing Asset At Amortized Value, Amount Capitalized

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Servicing Asset, Net

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Income from mortgage banking activities (fees and commissions) and servicing real estate mortgages, credit cards, and other financial assets held by others net of any related impairment of capitalized service costs. Also includes any premiums received in lieu of regular servicing fees on such loans only as earned over the life of the loans.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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-Subsection Instruction 3
-Publisher SEC

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The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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The cash inflow from sales of loans that are secured with real estate mortgages and are held with the intention to resell in the near future.

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Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

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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.

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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 of amortization 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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Value of input used to measure servicing asset.

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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.

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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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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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