XML 84 R57.htm IDEA: XBRL DOCUMENT v3.24.0.1
Summary of significant accounting policies - Earnings Per Share (HEI only) (Details) - shares
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Antidilutive securities outstanding (in shares)   0 0
Restricted stock units      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Antidilutive securities outstanding (in shares) 65,078