Net loss per unitholders' interest (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Oct. 31, 2023	Oct. 31, 2022
Earnings Distribution Allocation [Line Items]
Net earnings attributable to Ferrellgas Partners, L.P.	$ (17,556)	$ (4,545)
Less: General partner's interest in net earnings (loss)	(175)	(45)
Undistributed net earnings (loss) attributable to Class A unitholders	$ (33,632)	(20,751)
Allocation of earnings to Class B units relative to allocation to Class A units	6
Preferred Units
Earnings Distribution Allocation [Line Items]
Less: Distributions to preferred unitholders	$ 16,251	$ 16,251
Class A Limited Partner Units
Earnings Distribution Allocation [Line Items]
Weighted average Class A Units outstanding (in thousands)	4,857,600	4,857,600
Basic and diluted net earnings (loss) per Class A Unit	$ (6.92)	$ (4.27)
Class B Limited Partner Units
Earnings Distribution Allocation [Line Items]
Percentage of allocated earnings	100.00%