Bank segment - Mortgage Servicing Rights (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) loan	Sep. 30, 2023 USD ($) loan	Dec. 31, 2023 USD ($)
Servicing contracts
Prepayment rate:
25 basis points adverse rate change	$ (232)		$ (232)		$ (90)
50 basis points adverse rate change	(494)		(494)		(204)
Discount rate:
25 basis points adverse rate change	(171)		(171)		(203)
50 basis points adverse rate change	(340)		$ (340)		(402)
American Savings Bank (ASB)
Servicing Asset at Amortized Cost [Line Items]
Number of mortgage loans repurchased | loan			0	0
Mortgage service fees	900	$ 900	$ 2,600	$ 2,700
Mortgage servicing rights
Servicing asset - beginning balance			8,169
Servicing asset - ending balance	7,722		7,722
American Savings Bank (ASB) | Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	28,100	21,500	85,400	36,100
Gain on sale of mortgage loans	400	300	1,200	700
American Savings Bank (ASB) | Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	18,284		18,284		18,241
Accumulated amortization	(10,562)		(10,562)		(10,072)
Valuation allowance	0	0	0	0	0
Net carrying amount	7,722	8,376	7,722	8,376	8,169
Mortgage servicing rights
Servicing asset - beginning balance	7,906	8,495	8,169	9,047
Amount capitalized	171	184	548	319
Amortization	(355)	(303)	(995)	(990)
Other-than-temporary impairment	0	0	0	0
Servicing asset - ending balance	7,722	8,376	7,722	8,376
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	$ 1,392,423		$ 1,392,423		$ 1,402,736
American Savings Bank (ASB) | Servicing contracts | Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0361		0.0361		0.0347
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	0.0747		0.0747		0.0571