Bank segment (HEI only) - Off Balance Sheet Arrangements and Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
American Savings Bank (ASB)
Guarantees
FDIC insurance assessment	$ 3,200	$ 3,000
American Savings Bank (ASB) | Indemnification Agreement
Guarantees
Accrued indemnification litigation obligation	1,100
Reserve for Off-balance Sheet Activities
Guarantees
Unused Commitments to Extend Credit	1,842,799	1,832,082
Home equity line of credit
Guarantees
Unused Commitments to Extend Credit	1,146,339	1,096,532
Commercial and commercial real estate
Guarantees
Unused Commitments to Extend Credit	577,410	631,780
Consumer loans
Guarantees
Unused Commitments to Extend Credit	64,762	60,198
Residential 1-4 family
Guarantees
Unused Commitments to Extend Credit	38,271	24,863
Commercial and financial standby letters of credit
Guarantees
Unused Commitments to Extend Credit	$ 16,017	$ 18,709