Bank segment (HEI only) - Off Balance Sheet Arrangements and Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended
	Sep. 30, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
American Savings Bank (ASB)
Guarantees
Minimum reserve ratio	1.36%
FDIC insurance assessment		$ 3,200	$ 2,300	$ 1,200
Reserve for Off-balance Sheet Activities
Guarantees
Unused commitments to extend credit		1,911,729	1,963,802
Home equity line of credit
Guarantees
Unused commitments to extend credit		1,181,496	1,248,773
Commercial real estate
Guarantees
Unused commitments to extend credit		612,158	574,281
Consumer
Guarantees
Unused commitments to extend credit		62,090	69,168
Residential 1-4 family
Guarantees
Unused commitments to extend credit		44,262	57,862
Commercial and financial standby letters of credit
Guarantees
Unused commitments to extend credit		$ 11,723	$ 13,718