Bank segment (HEI only) - Credit Risk Profile by Internally Assigned Grade for Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Credit risk profile by internally assigned grade for loans
Total financing receivables	$ 5,120,664	$ 4,843,634	$ 4,671,577
Loans, Excluding Consumer Loans
Credit risk profile by internally assigned grade for loans
Total financing receivables	1,566,109	1,428,553
Loans, Excluding Consumer Loans | Pass
Credit risk profile by internally assigned grade for loans
Total financing receivables	1,446,720	1,295,902
Loans, Excluding Consumer Loans | Special mention
Credit risk profile by internally assigned grade for loans
Total financing receivables	34,372	44,469
Loans, Excluding Consumer Loans | Substandard
Credit risk profile by internally assigned grade for loans
Total financing receivables	85,017	88,182
Loans, Excluding Consumer Loans | Doubtful
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Loans, Excluding Consumer Loans | Loss
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial real estate
Credit risk profile by internally assigned grade for loans
Total financing receivables	824,830	748,398	733,106
Commercial real estate | Pass
Credit risk profile by internally assigned grade for loans
Total financing receivables	756,747	658,288
Commercial real estate | Special mention
Credit risk profile by internally assigned grade for loans
Total financing receivables	4,451	32,871
Commercial real estate | Substandard
Credit risk profile by internally assigned grade for loans
Total financing receivables	63,632	57,239
Commercial real estate | Doubtful
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial real estate | Loss
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial construction
Credit risk profile by internally assigned grade for loans
Total financing receivables	70,605	92,264	108,273
Commercial construction | Pass
Credit risk profile by internally assigned grade for loans
Total financing receivables	68,316	89,974
Commercial construction | Special mention
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial construction | Substandard
Credit risk profile by internally assigned grade for loans
Total financing receivables	2,289	2,290
Commercial construction | Doubtful
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial construction | Loss
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial
Credit risk profile by internally assigned grade for loans
Total financing receivables	670,674	587,891	$ 544,828
Commercial | Pass
Credit risk profile by internally assigned grade for loans
Total financing receivables	621,657	547,640
Commercial | Special mention
Credit risk profile by internally assigned grade for loans
Total financing receivables	29,921	11,598
Commercial | Substandard
Credit risk profile by internally assigned grade for loans
Total financing receivables	19,096	28,653
Commercial | Doubtful
Credit risk profile by internally assigned grade for loans
Total financing receivables	0	0
Commercial | Loss
Credit risk profile by internally assigned grade for loans
Total financing receivables	$ 0	$ 0