Schedule I Parent Only Statements - Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Condensed Income Statements, Captions [Line Items]
General and administrative expense									$ 45,752	$ 59,994	$ 54,401
Operating income									148,670	113,028	(91,964)
Interest expense									(192,962)	(177,619)	(168,467)
Other income (expense), net									(460)	369	928
Income tax expense (benefit)									851	323	(2,678)
Net loss	$ (70,605)	$ (15,471)	$ 48,791	$ (45,717)	$ (217,797)	$ 11,062	$ (1,774)	$ (48,316)	(83,002)	(64,545)	(256,825)
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Equity in earnings (loss) of Ferrellgas, L.P.									(49,261)	(29,219)	(219,902)
General and administrative expense									116	14	137
Operating income									(49,377)	(29,233)	(220,039)
Interest expense									(33,073)	(34,984)	(34,521)
Income tax expense (benefit)									49	30	21
Net loss									$ (82,499)	$ (64,247)	$ (254,581)