Bank segment - Mortgage servicing rights (Details) - American Savings Bank (ASB) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Servicing Asset at Amortized Cost [Line Items]
Mortgage service fees	$ 900	$ 1,000	$ 1,800	$ 1,900
Mortgage servicing rights
Servicing asset - beginning balance			9,950
Servicing asset - ending balance	9,696		9,696
Residential loan
Servicing Asset at Amortized Cost [Line Items]
Proceeds from sale of residential loans	38,700	95,600	114,300	266,500
Gain on sale of mortgage loans	300	1,900	1,400	6,200
Servicing contracts
Changes in Carrying Value of MSRs
Gross carrying amount	19,341		19,341		$ 18,674
Accumulated amortization	(9,645)		(9,645)		(8,724)
Valuation allowance	0	0	0	0	0
Net carrying amount	9,696	10,754	9,696	10,754	9,950
Mortgage servicing rights
Servicing asset - beginning balance	10,024	10,689	9,950	10,280
Amount capitalized	204	1,023	923	2,570
Amortization	(532)	(958)	(1,177)	(2,096)
Other-than-temporary impairment	0	0	0	0
Servicing asset - ending balance	9,696	10,754	9,696	10,754
Valuation allowance for mortgage servicing rights
Valuation allowance, beginning balance	0	4	0	260
Provision	0	(4)	0	(260)
Other-than-temporary impairment	0	0	0	0
Valuation allowance, ending balance	0	$ 0	0	$ 0
Unpaid principal balance	1,483,877		1,483,877		1,481,899
Prepayment rate:
25 basis points adverse rate change	(111)		(111)		(714)
50 basis points adverse rate change	(244)		(244)		(1,608)
Discount rate:
25 basis points adverse rate change	(176)		(176)		(129)
50 basis points adverse rate change	$ (350)		$ (350)		$ (256)
Servicing contracts | Weighted average note rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0334		0.0334		0.0338
Servicing contracts | Weighted average discount rate
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0925		0.0925		0.0925
Servicing contracts | Weighted average prepayment speed
Valuation allowance for mortgage servicing rights
Weighted average measurement input	0.0655		0.0655		0.0977