Bank segment - Mortgage servicing rights (Details) - American Savings Bank (ASB) $ in Thousands	3 Months Ended
Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Servicing Asset at Amortized Cost [Line Items]
Mortgage service fees	$ 900	$ 900
Mortgage servicing rights
Servicing asset - beginning balance	9,950
Servicing asset - ending balance	10,024
Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	75,600	170,900
Gain on sale of mortgage loans	1,100	4,300
Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	19,137		$ 18,674
Accumulated amortization	(9,113)		(8,724)
Valuation allowance	0	(4)	0
Net carrying amount	10,024	10,685	9,950
Mortgage servicing rights
Servicing asset - beginning balance	9,950	10,280
Amount capitalized	719	1,547
Amortization	(645)	(1,138)
Other-than-temporary impairment	0	0
Servicing asset - ending balance	10,024	10,689
Valuation allowance for mortgage servicing rights
Valuation allowance, beginning balance	0	260
Provision	0	(256)
Other-than-temporary impairment	0	0
Valuation allowance, ending balance	0	$ 4
Unpaid principal balance	1,488,591		1,481,899
Prepayment rate:
25 basis points adverse rate change	(360)		(714)
50 basis points adverse rate change	(809)		(1,608)
Discount rate:
25 basis points adverse rate change	(160)		(129)
50 basis points adverse rate change	$ (318)		$ (256)
Servicing contracts \| Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0334		0.0338
Servicing contracts \| Weighted average discount rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0925		0.0925
Servicing contracts \| Weighted average prepayment speed
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0706		0.0977

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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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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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Sensitivity Analysis Of Fair Value, Transferor's Interests In Transferred Financial Assets, Impact Of 50 Basis Points Adverse Change In Discount Rate

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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
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Subsection Instruction 3

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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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