Bank segment (HEI only) - Allowance For Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	$ 55,533	$ 50,038	$ 45,618
Charge-offs	(16,813)	(14,245)	(6,426)
Recoveries	4,016	2,977	4,571
Provision	10,901	16,763	6,275
Valuation allowance, balance at the end of the period	53,637	55,533	50,038
Ending balance: individually evaluated for impairment	2,730	4,083	6,320
Ending balance: collectively evaluated for impairment	50,907	51,450	43,718
Financing Receivables:
Total financing receivables	4,671,577	4,743,619	4,622,068
Ending balance: individually evaluated for impairment	33,393	51,759	53,685
Ending balance: collectively evaluated for impairment	4,638,184	4,691,860	4,568,383
Residential 1-4 family
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	2,873	4,186	4,662
Charge-offs	(826)	(639)	(356)
Recoveries	157	421	226
Provision	698	(1,095)	(346)
Valuation allowance, balance at the end of the period	2,902	2,873	4,186
Ending balance: individually evaluated for impairment	1,248	1,352	1,453
Ending balance: collectively evaluated for impairment	1,654	1,521	2,733
Financing Receivables:
Total financing receivables	2,118,047	2,048,051	2,069,665
Ending balance: individually evaluated for impairment	18,284	19,854	22,457
Ending balance: collectively evaluated for impairment	2,099,763	2,028,197	2,047,208
Commercial real estate
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	16,004	11,342	8,954
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	(208)	4,662	2,388
Valuation allowance, balance at the end of the period	15,796	16,004	11,342
Ending balance: individually evaluated for impairment	65	80	0
Ending balance: collectively evaluated for impairment	15,731	15,924	11,342
Financing Receivables:
Total financing receivables	733,106	800,395	690,561
Ending balance: individually evaluated for impairment	1,016	1,569	1,188
Ending balance: collectively evaluated for impairment	732,090	798,826	689,373
Home equity line of credit
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	5,039	7,260	6,982
Charge-offs	(14)	(112)	(205)
Recoveries	308	59	80
Provision	2,189	(2,168)	403
Valuation allowance, balance at the end of the period	7,522	5,039	7,260
Ending balance: individually evaluated for impairment	647	215	442
Ending balance: collectively evaluated for impairment	6,875	4,824	6,818
Financing Receivables:
Total financing receivables	913,052	863,163	846,294
Ending balance: individually evaluated for impairment	8,188	6,158	3,225
Ending balance: collectively evaluated for impairment	904,864	857,005	843,069
Residential land
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	1,738	1,671	1,875
Charge-offs	(210)	(138)	0
Recoveries	482	461	507
Provision	(1,114)	(256)	(711)
Valuation allowance, balance at the end of the period	896	1,738	1,671
Ending balance: individually evaluated for impairment	47	789	891
Ending balance: collectively evaluated for impairment	849	949	780
Financing Receivables:
Total financing receivables	15,797	18,889	18,229
Ending balance: individually evaluated for impairment	1,265	3,629	5,683
Ending balance: collectively evaluated for impairment	14,532	15,260	12,546
Commercial construction
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	6,449	4,461	5,471
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	(1,778)	1,988	(1,010)
Valuation allowance, balance at the end of the period	4,671	6,449	4,461
Ending balance: individually evaluated for impairment	0	0	0
Ending balance: collectively evaluated for impairment	4,671	6,449	4,461
Financing Receivables:
Total financing receivables	108,273	126,768	100,796
Ending balance: individually evaluated for impairment	0	0	0
Ending balance: collectively evaluated for impairment	108,273	126,768	100,796
Residential construction
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	12	13	28
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	0	(1)	(15)
Valuation allowance, balance at the end of the period	12	12	13
Ending balance: individually evaluated for impairment	0	0	0
Ending balance: collectively evaluated for impairment	12	12	13
Financing Receivables:
Total financing receivables	14,910	16,080	14,089
Ending balance: individually evaluated for impairment	0	0	0
Ending balance: collectively evaluated for impairment	14,910	16,080	14,089
Commercial
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	16,618	17,208	14,017
Charge-offs	(4,006)	(5,943)	(1,074)
Recoveries	1,852	1,093	2,773
Provision	(3,613)	4,260	1,492
Valuation allowance, balance at the end of the period	10,851	16,618	17,208
Ending balance: individually evaluated for impairment	694	1,641	3,527
Ending balance: collectively evaluated for impairment	10,157	14,977	13,681
Financing Receivables:
Total financing receivables	544,828	692,051	758,659
Ending balance: individually evaluated for impairment	4,574	20,539	21,119
Ending balance: collectively evaluated for impairment	540,254	671,512	737,540
Consumer
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	6,800	3,897	3,629
Charge-offs	(11,757)	(7,413)	(4,791)
Recoveries	1,217	943	985
Provision	14,727	9,373	4,074
Valuation allowance, balance at the end of the period	10,987	6,800	3,897
Ending balance: individually evaluated for impairment	29	6	7
Ending balance: collectively evaluated for impairment	10,958	6,794	3,890
Financing Receivables:
Total financing receivables	223,564	178,222	123,775
Ending balance: individually evaluated for impairment	66	10	13
Ending balance: collectively evaluated for impairment	223,498	178,212	123,762
Unallocated
Allowance for loan losses:
Valuation allowance, balance at the beginning of the period	0	0	0
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	0	0	0
Valuation allowance, balance at the end of the period	0	0	0
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	0	0	0
Financing Receivables:
Total financing receivables
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment