Bank segment (HEI only) - Derivative Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative instrument
Net gains (losses) recognized in the Statement of Income	$ (59)	$ (137)	$ (111)
Not Designated as Hedging Instrument
Derivative instrument
Asset derivative	91	137
Liability derivative	43	30
Interest Rate Lock Commitments
Derivative instrument
Notional amount	10,180	13,669
Fair value	91	131
Interest Rate Lock Commitments \| Not Designated as Hedging Instrument
Derivative instrument
Asset derivative	91	133
Liability derivative	0	2
Interest Rate Lock Commitments \| Not Designated as Hedging Instrument \| Mortgage banking income
Derivative instrument
Net gains (losses) recognized in the Statement of Income	(40)	(290)	37
Forward commitments
Derivative instrument
Notional amount	10,132	14,465
Fair value	(43)	(24)
Forward commitments \| Not Designated as Hedging Instrument
Derivative instrument
Asset derivative	0	4
Liability derivative	43	28
Forward commitments \| Not Designated as Hedging Instrument \| Mortgage banking income
Derivative instrument
Net gains (losses) recognized in the Statement of Income	$ (19)	$ 153	$ (148)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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