Bank segment (HEI only) - Balance Sheets Data (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 169,208	$ 261,881	$ 278,452	$ 300,478
Investment securities
Available-for-sale, at fair value	1,388,533	1,401,198
Held-to-maturity, at amortized cost (fair value of $142,057 and $44,412 at December 31, 2018 and 2017, respectively)	141,875	44,515
Stock in Federal Home Loan Bank, at cost	9,958	9,706
Allowance for loan losses	(52,119)	(53,637)
Total loans, net	4,790,902	4,617,131
Loans held for sale, at lower of cost or fair value	1,805	11,250
Other	530,364	513,535
Goodwill	82,190	82,190
Total assets	13,104,051	12,534,160	11,881,981
LIABILITIES AND SHAREHOLDERS’ EQUITY
Other	580,788	521,018
Total liabilities	10,907,478	10,402,481
Commitments and contingencies
Retained earnings	543,623	476,836
Net unrealized losses on securities	(24,423)	(14,951)
Accumulated other comprehensive loss, net of tax benefits	(50,610)	(41,941)
Total shareholders’ equity	2,162,280	2,097,386	$ 2,066,753	$ 1,927,640
Total capitalization and liabilities	13,104,051	12,534,160
Other assets
Premises and equipment, net	4,830,118	4,460,248
Total other assets	530,364	513,535
Other liabilities
Total other liabilities	580,788	521,018
Held-to-maturity investment securities	142,057	44,412
American Savings Bank (ASB)
Assets
Cash and due from banks	122,059	140,934
Interest-bearing deposits	4,225	93,165
Investment securities
Available-for-sale, at fair value	1,388,533	1,401,198
Held-to-maturity, at amortized cost (fair value of $142,057 and $44,412 at December 31, 2018 and 2017, respectively)	141,875	44,515
Stock in Federal Home Loan Bank, at cost	9,958	9,706
Loans held for investment	4,843,021	4,670,768
Allowance for loan losses	(52,119)	(53,637)
Total loans, net	4,790,902	4,617,131
Loans held for sale, at lower of cost or fair value	1,805	11,250
Other	486,347	398,570
Goodwill	82,190	82,190
Total assets	7,027,894	6,798,659
LIABILITIES AND SHAREHOLDERS’ EQUITY
Deposit liabilities–noninterest-bearing	1,800,727	1,760,233
Deposit liabilities–interest-bearing	4,358,125	4,130,364
Other borrowings	110,040	190,859
Other	124,613	110,356
Total liabilities	6,393,505	6,191,812
Commitments and contingencies
Common stock	1	1
Additional paid in capital	347,170	345,018
Retained earnings	325,286	292,957
Net unrealized losses on securities	(24,423)	(14,951)
Retirement benefit plans	(13,645)	(16,178)
Accumulated other comprehensive loss, net of tax benefits	(38,068)	(31,129)
Total shareholders’ equity	634,389	606,847
Total capitalization and liabilities	7,027,894	6,798,659
Other assets
Bank-owned life insurance	151,172	148,775
Premises and equipment, net	214,415	136,270
Accrued interest receivable	20,140	18,724
Mortgage servicing rights	8,062	8,639
Low-income housing investments	67,626	59,016
Real estate acquired in settlement of loans, net	406	133
Other	24,526	27,013
Total other assets	486,347	398,570
Other liabilities
Accrued expenses	54,084	39,312
Federal and state income taxes payable	2,012	3,736
Cashier’s checks	26,906	27,000
Advance payments by borrowers	10,183	10,245
Other	31,428	30,063
Total other liabilities	124,613	110,356
Held-to-maturity investment securities	$ 142,057	$ 44,412