Financial instruments - Financial assets and liabilities measured at fair value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023
Assets:
Derivatives	$ 27,143	$ 21,578
Quoted Prices In Active Markets (Level 1)
Assets:
Derivatives	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	27,143	21,578
Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	$ 0	$ 0