Bank segment - Mortgage Servicing Rights (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) loan	Jun. 30, 2022 USD ($) loan	Dec. 31, 2022 USD ($)
Servicing contracts
Prepayment rate:
25 basis points adverse rate change	$ (72)		$ (72)		$ (92)
50 basis points adverse rate change	(169)		(169)		(214)
Discount rate:
25 basis points adverse rate change	(191)		(191)		(182)
50 basis points adverse rate change	(378)		$ (378)		(361)
American Savings Bank (ASB)
Servicing Asset at Amortized Cost [Line Items]
Number of mortgage loans repurchased | loan			0	0
Mortgage service fees	900	$ 900	$ 1,800	$ 1,800
Mortgage servicing rights
Servicing asset - beginning balance			9,047
Servicing asset - ending balance	8,495		8,495
American Savings Bank (ASB) | Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	8,900	38,700	14,600	114,300
Gain on sale of mortgage loans	300	300	400	1,400
American Savings Bank (ASB) | Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	17,953		17,953		19,544
Accumulated amortization	(9,458)		(9,458)		(10,497)
Valuation allowance	0	0	0	0	0
Net carrying amount	8,495	9,696	8,495	9,696	9,047
Mortgage servicing rights
Servicing asset - beginning balance	8,745	10,024	9,047	9,950
Amount capitalized	84	204	135	923
Amortization	(334)	(532)	(687)	(1,177)
Other-than-temporary impairment	0	0	0	0
Servicing asset - ending balance	8,495	9,696	8,495	9,696
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	$ 1,414,845		$ 1,414,845		$ 1,451,322
American Savings Bank (ASB) | Servicing contracts | Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0340		0.0340		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	0.0628		0.0628		0.0656