Bank segment (HEI only) - Credit risk profile - assigned grades (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross	$ 5,232,642	$ 5,067,821	$ 5,067,821
Total
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			1,566,109
Total | Pass
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			1,446,720
Total | Special mention
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			34,372
Total | Substandard
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			85,017
Total | Doubtful
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Total | Loss
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Real estate | Commercial real estate
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			824,830
Real estate | Commercial real estate | Pass
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			756,747
Real estate | Commercial real estate | Special mention
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			4,451
Real estate | Commercial real estate | Substandard
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			63,632
Real estate | Commercial real estate | Doubtful
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Real estate | Commercial real estate | Loss
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Real estate | Commercial construction
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			70,605
Real estate | Commercial construction | Pass
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			68,316
Real estate | Commercial construction | Special mention
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Real estate | Commercial construction | Substandard
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			2,289
Real estate | Commercial construction | Doubtful
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Real estate | Commercial construction | Loss
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Commercial
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			670,674
Commercial | Pass
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			621,657
Commercial | Special mention
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			29,921
Commercial | Substandard
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			19,096
Commercial | Doubtful
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			0
Commercial | Loss
Credit risk profile by internally assigned grade for loans
Loans and leases receivable before fees, gross			$ 0