Derivative instruments and hedging activities - Effect on Comprehensive Income and Change in FV (Details) - Commodity Derivatives Propane - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2023	Oct. 31, 2022
Derivative instruments and hedging activities
Amount of gain (loss) recognized in AOCI on derivative	$ (13,472)	$ (36,185)
Amount of gain (loss) reclassified from AOCI into income	(3,184)
Cost of Sales
Derivative instruments and hedging activities
Amount of gain (loss) reclassified from AOCI into income		12,788
Amount of gain (loss) reclassified, ineffective portion	$ 0	$ 0