Net (loss) earnings per Unitholders' interest (Details)	12 Months Ended
	Jul. 31, 2025 USD ($) $ / shares shares	Jul. 31, 2024 USD ($) $ / shares shares	Jul. 31, 2023 USD ($) $ / shares shares
Earnings Distribution Allocation
Value of dilutive securities	$ 0
Net (loss) earnings attributable to Ferrellgas Partners, L.P.	(15,566,000)	$ 110,216,000	$ 136,881,000
Less: Allocation of undistributed net earnings to Class B units			11,030,000
Less: General partner's interest in net (loss) earnings	$ (155,000)	1,102,000	1,368,000
Allocation of earnings to Class B units relative to allocation to Class A units	6
Preferred Units
Earnings Distribution Allocation
Less: Distributions to preferred unitholders	$ 64,068,000	64,778,000	64,314,000
Class A Limited Partner Units
Earnings Distribution Allocation
Undistributed net earnings (loss) attributable to Class A unitholders	$ (79,479,000)	$ (55,660,000)	$ 10,171,000
Weighted Average Number of Shares Outstanding, Basic | shares	4,857,600	4,857,600	4,857,600
Weighted average Class A Units outstanding (in thousands) | shares	4,857,600	4,857,600	4,857,600
Basic and diluted net earnings (loss) per Class A Unit | $ / shares	$ (16.36)	$ (11.46)	$ 2.09
Class B Limited Partner Units
Earnings Distribution Allocation
Less: Distributions to preferred unitholders		$ 99,996,000	$ 49,998,000