Net earnings (loss) per unitholders' interest (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2022	Apr. 30, 2021
Earnings Distribution Allocation [Line Items]
Net earnings attributable to Ferrellgas Partners, L.P.	$ 67,586	$ (66,794)	$ 167,385	$ (49,589)
Less: General partner's interest in net earnings	675	(748)	1,673	(576)
Limited partner unitholders' interest in net earnings (loss)	7,336	(74,057)	$ 16,668	(57,024)
Allocation of earnings to Class B units relative to allocation to Class A units			6
Preferred Units
Earnings Distribution Allocation [Line Items]
Less: Distributions	$ 15,558	$ 8,011	$ 49,037	$ 8,011
Class A Limited Partner Units
Earnings Distribution Allocation [Line Items]
Weighted average common units outstanding, basic and diluted	4,857,600	4,857,600	4,857,600	4,857,600
Basic and diluted net earnings (loss) per limited partner unit	$ 1.51	$ (15.25)	$ 3.43	$ (11.74)
Class B Limited Partner Units
Earnings Distribution Allocation [Line Items]
Less: Distributions			$ 49,998
Less: Allocation of undistributed net earnings to Class B units	$ 44,017		$ 50,009
Percentage of allocated earnings			100.00%

[Line Items] for Earnings Distribution Allocation [Table]

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