Bank segment (HEI only) - Securities Sold Under Agreements to Repurchase, Including Related Collateral Received From or Pledged to Counterparties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Securities sold under agreements to repurchase
Gross amount of recognized liabilities, repurchase agreements	$ 93,000	$ 229,000
Gross amount offset in the Balance Sheet	0	0
Net amount of liabilities presented in the Balance Sheet, repurchase agreements	93,000	229,000
Financial instruments	116,000	261,000
Cash collateral pledged		0		$ 0
Identical securities
Securities sold under agreements to repurchase
Repurchase liability	92,618	228,582	$ 191,000
Average amount outstanding during the year	170,000	219,000	155,000
Maximum amount outstanding as of any month-end	$ 229,000	$ 277,000	$ 195,000
Weighted-average interest rate as of end of the period (as a percent)	0.23%	1.24%	1.45%
Weighted-average interest rate during the year (as a percent)	1.43%	1.29%	1.67%
Weighted-average remaining days to maturity as of end of the period	6 days	117 days	343 days
Financial institution
Securities sold under agreements to repurchase
Net amount of liabilities presented in the Balance Sheet, repurchase agreements	$ 0	$ 50,000
Financial instruments	0	56,000
Cash collateral pledged		0		0
Government entities
Securities sold under agreements to repurchase
Net amount of liabilities presented in the Balance Sheet, repurchase agreements	14,000	56,000
Financial instruments	15,000	61,000
Cash collateral pledged		0		0
Commercial account holders
Securities sold under agreements to repurchase
Net amount of liabilities presented in the Balance Sheet, repurchase agreements	79,000	123,000
Financial instruments	$ 101,000	144,000
Cash collateral pledged		$ 0		$ 0