Bank segment (HEI only) - Collateral-dependent Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Nonaccrual [Line Items]
Total	$ 5,345,226	$ 5,120,664	$ 4,843,634
Real estate | Residential 1-4 family
Financing Receivable, Nonaccrual [Line Items]
Total	2,144,239
Real estate | Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Total	983,865
Real estate | Home equity  line of credit
Financing Receivable, Nonaccrual [Line Items]
Total	963,578
Real estate | Residential land
Financing Receivable, Nonaccrual [Line Items]
Total	15,617
Commercial
Financing Receivable, Nonaccrual [Line Items]
Total	936,748	$ 670,674	$ 587,891
Residential real estate property | Real estate | Residential 1-4 family
Financing Receivable, Nonaccrual [Line Items]
Total	2,541
Residential real estate property | Real estate | Home equity  line of credit
Financing Receivable, Nonaccrual [Line Items]
Total	1,567
Residential real estate property | Real estate | Residential land
Financing Receivable, Nonaccrual [Line Items]
Total	300
Commercial real estate | Real estate | Commercial real estate
Financing Receivable, Nonaccrual [Line Items]
Total	2,875
Business assets | Commercial
Financing Receivable, Nonaccrual [Line Items]
Total	934
Collateral Pledged
Financing Receivable, Nonaccrual [Line Items]
Total	8,217
Collateral Pledged | Real estate
Financing Receivable, Nonaccrual [Line Items]
Total	$ 7,283