Goodwill and intangible assets, net - Components (Details) - USD ($) $ in Thousands	Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2020
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill, gross carrying amount	$ 257,099	$ 246,946
Goodwill, net	257,099	246,946	$ 247,195
Amortizable intangible assets, gross carrying amount	486,738	481,754
Amortizable intangible assets, accumulated amortization	(440,121)	(432,032)
Amortizable intangible assets, net	46,617	49,722
Intangible assets gross excluding goodwill	537,759	532,775
Intangible assets amortization and impairment net excluding goodwill	(440,121)	(432,032)
Intangible assets net excluding goodwill	97,638	100,743
Trade Names And Trademarks [Member]
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	51,021	51,021
Customer Lists [Member]
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Amortizable intangible assets, gross carrying amount	456,181	451,922
Amortizable intangible assets, accumulated amortization	(412,548)	(405,490)
Amortizable intangible assets, net	43,633	46,432
Non-Compete Agreements [Member]
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Amortizable intangible assets, gross carrying amount	27,044	26,319
Amortizable intangible assets, accumulated amortization	(24,060)	(23,029)
Amortizable intangible assets, net	2,984	3,290
Other Intangible Assets [Member]
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Amortizable intangible assets, gross carrying amount	3,513	3,513
Amortizable intangible assets, accumulated amortization	(3,513)	(3,513)
Amortizable intangible assets, net	0	0
Ferrellgas, L.P. [Member]
Finite Lived And Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill, net	257,099	246,946
Amortizable intangible assets, accumulated amortization	(440,121)	(432,032)
Intangible assets net excluding goodwill	$ 97,638	$ 100,743