Bank segment (HEI only) - Mortgage Servicing Rights and Valuation Allowance Roll Forward (Details) - American Savings Bank (ASB) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Mortgage Servicing Rights [Roll Forward]
Beginning balance	$ 8,884
Ending balance	9,373	$ 8,884
Allowance for mortgage-servicing assets – bank
Mortgage Servicing Rights [Roll Forward]
Beginning balance	8,884	11,749	$ 11,938
Amount capitalized	2,740	3,123	1,637
Amortization	(2,251)	(2,682)	(1,731)
Sale of mortgage servicing rights	0	(3,302)	0
Other-than-temporary impairment	0	(4)	(95)
Ending balance	9,373	8,884	11,749
Valuation Allowance [Roll Forward]
Valuation allowance, beginning balance	0	209	251
Provision (recovery)	0	(205)	53
Other-than-temporary impairment	0	(4)	(95)
Valuation allowance, ending balance	0	0	209
Net carrying amount	9,373	$ 8,884	$ 11,540
Estimated Aggregate Amortization Expenses of Mortgage Servicing Rights [Abstract]
2017	1,300
2018	1,200
2019	1,000
2020	900
2021	$ 800