Bank segment (HEI only) - Investment Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less	$ 60,200
Due after one year through five years	75,694
Due after five years through ten years	53,225
Due after ten years	15,427
Amortized cost, available-for-sale securities with a single maturity date	204,546
Mortgage-related securities-FNMA, FHLMC and GNMA - amortized cost	1,024,892
Total amortized cost	1,229,438	$ 1,421,897
Mortgage-related securities-FNMA, FHLMC and GNMA, amortized cost basis	139,451
Debt Securities, Held-to-maturity	139,451	141,875
Fair value
Due in one year or less	60,249
Due after one year through five years	77,225
Due after five years through ten years	53,540
Due after ten years	15,427
Available-for-sale securities with a single maturity date	206,441
Mortgage-related securities-FNMA, FHLMC and GNMA - fair value	1,026,385
Total fair value	1,232,826	1,388,533
Mortgage-related securities - FNMA, FHLMC and GNMA, Fair Value	143,467
Held-to-maturity securities, Fair Value	143,467	142,057
Gains (losses) from sales of available-for-sale investments
Proceeds	19,810	0	$ 0
Gross gains	700	0	0
Gross losses	0	0	0
Interest income from taxable and non-taxable investment securities
Taxable	31,847	37,153	28,398
Non-taxable	1,074	609	425
Total	32,921	37,762	$ 28,823
Available-for-sale securities pledged at carrying value	546,000	546,000
Available-for-sale securities, pledged at carrying value as collateral for securities sold under agreements to repurchase	130,000	92,000
Stock in federal home loan bank at cost	8,434	9,958
FHLB Des Moines
Interest income from taxable and non-taxable investment securities
Stock in federal home loan bank at cost	$ 8,400	$ 10,000