Bank segment (HEI only) - Carrying Amount of Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Recorded investment:
With no related allowance recorded	$ 14,037	$ 16,349
With an allowance recorded	26,700	23,348
Recorded investment	40,737	39,697
Unpaid principal balance:
With no related allowance recorded	15,123	18,372
With an allowance recorded	26,762	23,580
Unpaid principal balance	41,885	41,952
Related Allowance	2,691	2,222
Average recorded investment, with no related allowance recorded	17,422	15,630	$ 15,378
Average recorded investment, with an allowance recorded	27,972	22,360	21,160
Average recorded investment	45,394	37,990	36,538
Interest income recognized, with no related allowance recorded	1,400	588	599
Interest income recognized, with an allowance recorded	1,119	974	1,621
Interest income recognized	2,519	1,562	2,220
Residential 1-4 family
Recorded investment:
With no related allowance recorded	6,817	7,822
With an allowance recorded	8,783	8,672
Recorded investment	15,600	16,494
Unpaid principal balance:
With no related allowance recorded	7,207	8,333
With an allowance recorded	8,835	8,875
Unpaid principal balance	16,042	17,208
Related Allowance	898	876
Average recorded investment, with no related allowance recorded	8,169	8,595	9,440
Average recorded investment, with an allowance recorded	8,390	8,878	9,818
Average recorded investment	16,559	17,473	19,258
Interest income recognized, with no related allowance recorded	907	445	316
Interest income recognized, with an allowance recorded	359	363	493
Interest income recognized	1,266	808	809
Commercial real estate
Recorded investment:
With no related allowance recorded	195	0
With an allowance recorded	853	915
Recorded investment	1,048	915
Unpaid principal balance:
With no related allowance recorded	200	0
With an allowance recorded	853	915
Unpaid principal balance	1,053	915
Related Allowance	2	7
Average recorded investment, with no related allowance recorded	16	0	91
Average recorded investment, with an allowance recorded	886	982	1,241
Average recorded investment	902	982	1,332
Interest income recognized, with no related allowance recorded	0	0	11
Interest income recognized, with an allowance recorded	37	42	54
Interest income recognized	37	42	65
Home equity line of credit
Recorded investment:
With no related allowance recorded	1,984	2,743
With an allowance recorded	10,089	12,057
Recorded investment	12,073	14,800
Unpaid principal balance:
With no related allowance recorded	2,135	3,004
With an allowance recorded	10,099	12,086
Unpaid principal balance	12,234	15,090
Related Allowance	322	701
Average recorded investment, with no related allowance recorded	2,020	2,206	1,976
Average recorded investment, with an allowance recorded	11,319	10,617	5,045
Average recorded investment	13,339	12,823	7,021
Interest income recognized, with no related allowance recorded	84	75	101
Interest income recognized, with an allowance recorded	567	440	251
Interest income recognized	651	515	352
Residential land
Recorded investment:
With no related allowance recorded	3,091	2,030
With an allowance recorded	0	29
Recorded investment	3,091	2,059
Unpaid principal balance:
With no related allowance recorded	3,294	2,228
With an allowance recorded	0	29
Unpaid principal balance	3,294	2,257
Related Allowance	0	6
Average recorded investment, with no related allowance recorded	2,662	1,532	1,094
Average recorded investment, with an allowance recorded	27	37	1,308
Average recorded investment	2,689	1,569	2,402
Interest income recognized, with no related allowance recorded	129	40	117
Interest income recognized, with an allowance recorded	0	3	97
Interest income recognized	129	43	214
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	1,948	3,722
With an allowance recorded	6,470	1,618
Recorded investment	8,418	5,340
Unpaid principal balance:
With no related allowance recorded	2,285	4,775
With an allowance recorded	6,470	1,618
Unpaid principal balance	8,755	6,393
Related Allowance	1,015	628
Average recorded investment, with no related allowance recorded	4,534	3,275	2,776
Average recorded investment, with an allowance recorded	6,990	1,789	3,691
Average recorded investment	11,524	5,064	6,467
Interest income recognized, with no related allowance recorded	276	28	54
Interest income recognized, with an allowance recorded	132	122	723
Interest income recognized	408	150	777
Consumer
Recorded investment:
With no related allowance recorded	2	32
With an allowance recorded	505	57
Recorded investment	507	89
Unpaid principal balance:
With no related allowance recorded	2	32
With an allowance recorded	505	57
Unpaid principal balance	507	89
Related Allowance	454	4
Average recorded investment, with no related allowance recorded	21	22	1
Average recorded investment, with an allowance recorded	360	57	57
Average recorded investment	381	79	58
Interest income recognized, with no related allowance recorded	4	0	0
Interest income recognized, with an allowance recorded	24	4	3
Interest income recognized	$ 28	$ 4	$ 3