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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.

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This element represents disclosure of the total aggregate cash dividends paid to the entity by consolidated subsidiaries, by unconsolidated subsidiaries, and by 50% or less owned persons accounted for using the equity method.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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The fair value of notes issued in noncash investing and financing activities.

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The value of notes retired (or transferred to another entity) in noncash investing or financing transactions.

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SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Less unamortized debt issuance costs	$ (2,350,000)	$ (2,599,000)
Long-term debt, net—other than bank	1,964,365,000	1,879,641,000
Aggregate principal payments, fiscal year maturity:
2020	102,000,000
2021	54,000,000
2022	213,000,000
2023	154,000,000
2024	5,000,000
Parent Company
Condensed Financial Statements, Captions [Line Items]
Less unamortized debt issuance costs	(936,000)	(1,126,000)
Long-term debt, net—other than bank	399,064,000	398,874,000
Aggregate principal payments, fiscal year maturity:
2020	0
2021	50,000,000
2022	150,000,000
2023	50,000,000
2024	0
Thereafter	150,000,000
Cash dividends paid	157,000,000	154,000,000	$ 125,000,000
Parent Company \| ASB Hawaii, Inc. \| Consolidated subsidiary
Aggregate principal payments, fiscal year maturity:
Accounts receivable reduction	2,300,000	2,300,000	2,800,000
HEI notes payable increase to ASHI	2,300,000	2,300,000	2,800,000
Parent Company \| Hamakua Energy Partners, L.P. (HEP)
Aggregate principal payments, fiscal year maturity:
Notes receivable converted into equity			$ 3,600,000
Parent Company \| Self Insured United States Longshore and Horbor Bond
Aggregate principal payments, fiscal year maturity:
Maximum undiscounted exposure	600,000
Parent Company \| Self Insured Automobile Bond
Aggregate principal payments, fiscal year maturity:
Maximum undiscounted exposure	700,000
Parent Company \| HEI loan 2.99%, due 2022
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 150,000,000	150,000,000
Debt instrument, stated interest rate	2.99%
Parent Company \| HEI 5.67% senior notes, due 2021
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 50,000,000	50,000,000
Debt instrument, stated interest rate	5.67%
Parent Company \| HEI 3.99% senior notes, due 2023
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 50,000,000	50,000,000
Debt instrument, stated interest rate	3.99%
Parent Company \| HEI 4.58% senior notes, due 2025
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 50,000,000	50,000,000
Debt instrument, stated interest rate	4.58%
Parent Company \| HEI 4.72% senior notes, due 2028
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 100,000,000	$ 100,000,000
Debt instrument, stated interest rate	4.72%