Bank segment (HEI only) - Carrying Amount of Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Recorded investment:
With no related allowance recorded	$ 16,349	$ 14,072
With an allowance recorded	23,348	19,321
Recorded investment	39,697	33,393
Unpaid principal balance:
With no related allowance recorded	18,372	16,041
With an allowance recorded	23,580	19,574
Unpaid principal balance	41,952	35,615
Related Allowance	2,222	2,730
Average recorded investment, with no related allowance recorded	15,630	15,378	$ 22,579
Average recorded investment, with an allowance recorded	22,360	21,160	36,398
Average recorded investment	37,990	36,538	58,977
Interest income recognized, with no related allowance recorded	588	599	783
Interest income recognized, with an allowance recorded	974	1,621	1,271
Interest income recognized	1,562	2,220	2,054
Residential 1-4 family
Recorded investment:
With no related allowance recorded	7,822	9,097
With an allowance recorded	8,672	9,187
Recorded investment	16,494	18,284
Unpaid principal balance:
With no related allowance recorded	8,333	9,644
With an allowance recorded	8,875	9,390
Unpaid principal balance	17,208	19,034
Related Allowance	876	1,248
Average recorded investment, with no related allowance recorded	8,595	9,440	10,136
Average recorded investment, with an allowance recorded	8,878	9,818	11,589
Average recorded investment	17,473	19,258	21,725
Interest income recognized, with no related allowance recorded	445	316	324
Interest income recognized, with an allowance recorded	363	493	457
Interest income recognized	808	809	781
Commercial real estate
Recorded investment:
With no related allowance recorded	0	0
With an allowance recorded	915	1,016
Recorded investment	915	1,016
Unpaid principal balance:
With no related allowance recorded	0	0
With an allowance recorded	915	1,016
Unpaid principal balance	915	1,016
Related Allowance	7	65
Average recorded investment, with no related allowance recorded	0	91	1,124
Average recorded investment, with an allowance recorded	982	1,241	1,962
Average recorded investment	982	1,332	3,086
Interest income recognized, with no related allowance recorded	0	11	0
Interest income recognized, with an allowance recorded	42	54	15
Interest income recognized	42	65	15
Home equity line of credit
Recorded investment:
With no related allowance recorded	2,743	1,496
With an allowance recorded	12,057	6,692
Recorded investment	14,800	8,188
Unpaid principal balance:
With no related allowance recorded	3,004	1,789
With an allowance recorded	12,086	6,736
Unpaid principal balance	15,090	8,525
Related Allowance	701	647
Average recorded investment, with no related allowance recorded	2,206	1,976	1,105
Average recorded investment, with an allowance recorded	10,617	5,045	3,765
Average recorded investment	12,823	7,021	4,870
Interest income recognized, with no related allowance recorded	75	101	23
Interest income recognized, with an allowance recorded	440	251	137
Interest income recognized	515	352	160
Residential land
Recorded investment:
With no related allowance recorded	2,030	1,143
With an allowance recorded	29	122
Recorded investment	2,059	1,265
Unpaid principal balance:
With no related allowance recorded	2,228	1,434
With an allowance recorded	29	122
Unpaid principal balance	2,257	1,556
Related Allowance	6	47
Average recorded investment, with no related allowance recorded	1,532	1,094	1,518
Average recorded investment, with an allowance recorded	37	1,308	2,964
Average recorded investment	1,569	2,402	4,482
Interest income recognized, with no related allowance recorded	40	117	66
Interest income recognized, with an allowance recorded	3	97	206
Interest income recognized	43	214	272
Commercial construction
Recorded investment:
With no related allowance recorded	0	0
With an allowance recorded	0	0
Recorded investment	0	0
Unpaid principal balance:
With no related allowance recorded	0	0
With an allowance recorded	0	0
Unpaid principal balance	0	0
Related Allowance	0	0
Average recorded investment, with no related allowance recorded	0	0	0
Average recorded investment, with an allowance recorded	0	0	0
Average recorded investment	0	0	0
Interest income recognized, with no related allowance recorded	0	0	0
Interest income recognized, with an allowance recorded	0	0	0
Interest income recognized	0	0	0
Residential construction
Recorded investment:
With no related allowance recorded	0	0
With an allowance recorded	0	0
Recorded investment	0	0
Unpaid principal balance:
With no related allowance recorded	0	0
With an allowance recorded	0	0
Unpaid principal balance	0	0
Related Allowance	0	0
Average recorded investment, with no related allowance recorded	0	0	0
Average recorded investment, with an allowance recorded	0	0	0
Average recorded investment	0	0	0
Interest income recognized, with no related allowance recorded	0	0	0
Interest income recognized, with an allowance recorded	0	0	0
Interest income recognized	0	0	0
Commercial
Recorded investment:
With no related allowance recorded	3,722	2,328
With an allowance recorded	1,618	2,246
Recorded investment	5,340	4,574
Unpaid principal balance:
With no related allowance recorded	4,775	3,166
With an allowance recorded	1,618	2,252
Unpaid principal balance	6,393	5,418
Related Allowance	628	694
Average recorded investment, with no related allowance recorded	3,275	2,776	8,694
Average recorded investment, with an allowance recorded	1,789	3,691	16,106
Average recorded investment	5,064	6,467	24,800
Interest income recognized, with no related allowance recorded	28	54	370
Interest income recognized, with an allowance recorded	122	723	456
Interest income recognized	150	777	826
Consumer
Recorded investment:
With no related allowance recorded	32	8
With an allowance recorded	57	58
Recorded investment	89	66
Unpaid principal balance:
With no related allowance recorded	32	8
With an allowance recorded	57	58
Unpaid principal balance	89	66
Related Allowance	4	29
Average recorded investment, with no related allowance recorded	22	1	2
Average recorded investment, with an allowance recorded	57	57	12
Average recorded investment	79	58	14
Interest income recognized, with no related allowance recorded	0	0	0
Interest income recognized, with an allowance recorded	4	3	0
Interest income recognized	$ 4	$ 3	$ 0