Bank segment (HEI only) - Key Assumptions Used in Estimating the Fair Value of ASB's Mortgage Servicing Rights (Details) - Allowance for mortgage-servicing assets – bank $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Prepayment rate:
25 basis points adverse rate change	$ (714)	$ (738)
50 basis points adverse rate change	(1,608)	(1,445)
Discount rate:
25 basis points adverse rate change	(129)	(68)
50 basis points adverse rate change	(256)	(135)
American Savings Bank (ASB)
Mortgage Servicing Rights
Unpaid principal balance	$ 1,481,899	$ 1,450,312
Weighted average note rate	3.38%	3.68%
American Savings Bank (ASB) | Weighted average discount rate
Mortgage Servicing Rights
Weighted average measurement input	0.0925	0.0925
American Savings Bank (ASB) | Weighted average prepayment speed
Mortgage Servicing Rights
Weighted average measurement input	0.0977	0.1770