Bank segment - Mortgage Servicing Rights (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) loan	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($) loan	Dec. 31, 2023 USD ($)
Servicing contracts
Prepayment rate:
25 basis points adverse rate change	$ (133)		$ (133)		$ (90)
50 basis points adverse rate change	(296)		(296)		(204)
Discount rate:
25 basis points adverse rate change	(185)		(185)		(203)
50 basis points adverse rate change	$ (367)		(367)		(402)
American Savings Bank (ASB)
Servicing Asset at Amortized Cost [Line Items]
Number of mortgage loans repurchased | loan	0			0
Mortgage service fees	$ 800	$ 900	1,700	$ 1,800
Mortgage servicing rights
Servicing asset - beginning balance			8,169
Servicing asset - ending balance	7,906		7,906
American Savings Bank (ASB) | Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	30,900	8,900	57,300	14,600
Gain on sale of mortgage loans	400	300	800	400
American Savings Bank (ASB) | Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	18,114		18,114		18,241
Accumulated amortization	(10,208)		(10,208)		(10,072)
Valuation allowance	0	0	0	0	0
Net carrying amount	7,906	8,495	7,906	8,495	8,169
Mortgage servicing rights
Servicing asset - beginning balance	8,050	8,745	8,169	9,047
Amount capitalized	179	84	377	135
Amortization	(323)	(334)	(640)	(687)
Other-than-temporary impairment	0	0	0	0
Servicing asset - ending balance	7,906	8,495	7,906	8,495
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	$ 1,399,592		$ 1,399,592		$ 1,402,736
American Savings Bank (ASB) | Servicing contracts | Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0357		0.0357		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	0.0681		0.0681		0.0571