Bank segment (HEI only) - Reconciliation of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Revenues	$ 658,597	$ 673,185	$ 632,281	$ 591,562	$ 617,395	$ 646,055	$ 566,244	$ 550,960	$ 2,555,625	$ 2,380,654	$ 2,602,982
Total interest expense									91,128	88,558	88,476
Total expenses									2,217,334	2,032,479	2,280,429
Operating income	$ 84,988	$ 109,545	$ 75,896	$ 67,862	$ 88,427	$ 105,442	$ 85,455	$ 68,851	338,291	348,175	322,553
American Savings Bank (ASB)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Interest and dividend income									236,078	218,958	199,902
Noninterest income									61,562	66,966	67,831
Revenues									297,640	285,924	267,733
Total interest expense									12,156	12,755	11,326
Provision for loan losses									10,901	16,763	6,275
Noninterest expense									175,867	169,054	166,320
Total expenses									198,924	198,572	183,921
Operating income									$ 98,716	$ 87,352	$ 83,812