Bank segment (HEI only) - Key Assumptions Used in Estimating the Fair Value of ASB's Mortgage Servicing Rights (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Loans receivable
Weighted average discount rate	2.517%
American Savings Bank (ASB)
Loans receivable
Weighted average discount rate	8.90%
Allowance for mortgage-servicing assets – bank
Prepayment rate:
25 basis points adverse rate change	$ (567)	$ (561)
50 basis points adverse rate change	(1,154)	(1,104)
Discount rate:
25 basis points adverse rate change	(128)	(111)
50 basis points adverse rate change	(254)	(220)
Allowance for mortgage-servicing assets – bank | American Savings Bank (ASB)
Loans receivable
Unpaid principal balance	$ 1,188,380	$ 1,097,314
Weighted average note rate	3.96%	4.05%
Weighted average discount rate	9.40%	9.60%
Weighted average prepayment speed	8.50%	9.30%