Credit agreement and changes in debt - HEI Private Placement (Details) - Senior Notes	Sep. 30, 2023 USD ($)
Series 2023A
Debt Instrument [Line Items]
Aggregate principal amount	$ 39,000,000
Fixed coupon interest rate	6.04%
Series 2023B
Debt Instrument [Line Items]
Aggregate principal amount	$ 61,000,000
Fixed coupon interest rate	6.10%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details