XML 50 R37.htm IDEA: XBRL DOCUMENT v3.10.0.1
Electric utility segment - HECO Capital Trust III (Details) - VIE, Not Primary Beneficiary - USD ($)
$ in Thousands
9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Variable Interest Entity [Line Items]      
Investments $ 51,500   $ 51,500
Investment income, interest 2,500 $ 2,500  
Trust Preferred Securities Subject to Mandatory Redemption | Hawaiian Electric Company      
Variable Interest Entity [Line Items]      
Convertible preferred stock 50,000   50,000
Distributions to holders of Trust Preferred Securities 2,400 2,400  
Trust Common Securities | Hawaiian Electric Company      
Variable Interest Entity [Line Items]      
Convertible preferred stock 1,500   $ 1,500
Common dividends on the trust common securities $ 75 $ 75