Bank segment (HEI only) - Balance Sheets Data (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) building	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Assets
Cash and due from banks	$ 196,813	$ 169,208
Investment securities
Available-for-sale, at fair value	1,232,826	1,388,533
Held-to-maturity, at amortized cost (fair value of $143,467 and $142,057 at December 31, 2019 and 2018, respectively)	139,451	141,875
Stock in Federal Home Loan Bank, at cost	8,434	9,958
Allowance for loan losses	(53,355)	(52,119)
Total loans, net	5,067,821	4,790,902
Loans held for sale, at lower of cost or fair value	12,286	1,805
Other	649,885	530,364
Goodwill	82,190	82,190
Total assets	13,745,251	13,104,051	$ 12,534,160
LIABILITIES AND SHAREHOLDERS’ EQUITY
Other	583,545	580,788
Total liabilities	11,430,698	10,907,478
Commitments and contingencies
Retained earnings	622,042	543,623
Net unrealized gains (losses) on securities	2,481	(24,423)
Accumulated other comprehensive loss, net of tax benefits	(20,039)	(50,610)
Total shareholders’ equity	2,280,260	2,162,280	$ 2,097,386	$ 2,066,753
Total capitalization and liabilities	13,745,251	13,104,051
Other assets
Premises and equipment, net	5,109,628	4,830,118
Total other assets	649,885	530,364
Other liabilities
Total other liabilities	583,545	580,788
Held-to-maturity investment securities	$ 143,467	142,057
Number of buildings sold | building	2
American Savings Bank (ASB)
Assets
Cash and due from banks	$ 129,770	122,059
Interest-bearing deposits	48,628	4,225
Investment securities
Available-for-sale, at fair value	1,232,826	1,388,533
Held-to-maturity, at amortized cost (fair value of $143,467 and $142,057 at December 31, 2019 and 2018, respectively)	139,451	141,875
Stock in Federal Home Loan Bank, at cost	8,434	9,958
Loans held for investment	5,121,176	4,843,021
Allowance for loan losses	(53,355)	(52,119)
Total loans, net	5,067,821	4,790,902
Loans held for sale, at lower of cost or fair value	12,286	1,805
Other	511,611	486,347
Goodwill	82,190	82,190
Total assets	7,233,017	7,027,894
LIABILITIES AND SHAREHOLDERS’ EQUITY
Deposit liabilities–noninterest-bearing	1,909,682	1,800,727
Deposit liabilities–interest-bearing	4,362,220	4,358,125
Other borrowings	115,110	110,040
Other	146,954	124,613
Total liabilities	6,533,966	6,393,505
Commitments and contingencies
Common stock	1	1
Additional paid in capital	349,453	347,170
Retained earnings	358,259	325,286
Net unrealized gains (losses) on securities	2,481	(24,423)
Retirement benefit plans	(11,143)	(13,645)
Accumulated other comprehensive loss, net of tax benefits	(8,662)	(38,068)
Total shareholders’ equity	699,051	634,389
Total capitalization and liabilities	7,233,017	7,027,894
Other assets
Bank-owned life insurance	157,465	151,172
Premises and equipment, net	204,449	214,415
Accrued interest receivable	19,365	20,140
Mortgage servicing rights	9,101	8,062
Low-income housing investments	66,302	67,626
Real estate acquired in settlement of loans, net	0	406
Other	54,929	24,526
Total other assets	511,611	486,347
Other liabilities
Accrued expenses	45,822	54,084
Federal and state income taxes payable	14,996	2,012
Cashier’s checks	23,647	26,906
Advance payments by borrowers	10,486	10,183
Other	52,003	31,428
Total other liabilities	146,954	124,613
Held-to-maturity investment securities	$ 143,467	$ 142,057