Summary of significant accounting policies - Summary Of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2020
Significant Accounting Policies [Line Items]
Current expense	$ 974	$ 739	$ 297
Deferred income tax expense	7	2	554
Income tax expense	981	741	851
Ferrellgas, L.P. [Member]
Significant Accounting Policies [Line Items]
Current expense	969	725	248
Deferred income tax expense	7	2	554
Income tax expense	$ 976	$ 727	$ 802