Supplemental Financial Statement Information (Narrative) (Details) $ in Thousands, gal in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2018 USD ($) gal	Apr. 30, 2017 USD ($)	Apr. 30, 2018 USD ($) gal	Apr. 30, 2017 USD ($)
Loss on sale of assets and other	$ 5,033	$ 2,393	$ 9,662	$ 8,861
Maximum term of supply procurement contracts			36 months
Net procurement of fixed priced propane in gallons | gal	70.7		70.7
Ferrellgas, L.P. [Member]
Loss on sale of assets and other	$ 5,033	$ 2,393	$ 9,662	$ 8,861
Maximum term of supply procurement contracts			36 months
Net procurement of fixed priced propane in gallons | gal	70.7		70.7
Midstream - Crude Oil Logistics [Member]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down			$ 35,500
Number of rail cars sold	1,292		1,292
Loss on sale of assets and other			$ 3,800
Proceeds from Sale of Property, Plant, and Equipment	$ 51,300
Gain (Loss) on Sale of Assets and Asset Impairment Charges			36,800
Other Assets, Noncurrent	$ 8,500		8,500
Midstream - Crude Oil Logistics [Member] | Ferrellgas, L.P. [Member]
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down			$ 35,500
Number of rail cars sold	1,292		1,292
Loss on sale of assets and other			$ 3,800
Proceeds from Sale of Property, Plant, and Equipment	$ 51,300
Gain (Loss) on Sale of Assets and Asset Impairment Charges			36,800
Other Assets, Noncurrent	$ 8,500		$ 8,500