Supplemental Information - Inventories (Details) $ in Thousands, gal in Millions	12 Months Ended
	Jul. 31, 2020 USD ($) gal	Jul. 31, 2019 USD ($)
Supplemental Financial Statement Information [Line Items]
Propane gas and related products	$ 58,733	$ 66,001
Appliances, parts and supplies	13,931	14,453
Inventories	$ 72,664	80,454
Supply procurement contract duration	36 months
Net procurement of fixed priced propane by Ferrellgas in gallons | gal	1.0
Ferrellgas, L.P. [Member]
Supplemental Financial Statement Information [Line Items]
Propane gas and related products	$ 58,733	66,001
Appliances, parts and supplies	13,931	14,453
Inventories	$ 72,664	$ 80,454
Supply procurement contract duration	36 months
Net procurement of fixed priced propane by Ferrellgas in gallons | gal	1.0