Supplemental Financial Statement Information (Narrative) (Details) gal in Millions	3 Months Ended	12 Months Ended
	Jul. 31, 2016 USD ($)	Jul. 31, 2017 USD ($) gal	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)
Asset Impairment Charges	$ 628,800,000	$ 0	$ 658,118,000	$ 0
Supply procurement contract duration		36 months
Net procurement of fixed priced propane by Ferrellgas in gallons | gal		109.6
Depreciation		$ 68,100,000	$ 85,800,000	61,300,000
Long Lived Assets Held-for-sale, Description		12	12
Ferrellgas, L.P. [Member]
Asset Impairment Charges	628,800,000	$ 0	$ 658,118,000	0
Net procurement of fixed priced propane by Ferrellgas in gallons | gal		109.6
Depreciation		$ 68,100,000	$ 85,800,000	$ 61,300,000
Long Lived Assets Held-for-sale, Description		12	12
Maximum [Member] | Ferrellgas, L.P. [Member]
Supply procurement contract duration		36 months
Vehicles, Including Transport Trailers [Member] | Midstream - Crude Oil Logistics [Member]
Assets Sold			134
Vehicles, Including Transport Trailers [Member] | Midstream - Crude Oil Logistics [Member] | Ferrellgas, L.P. [Member]
Assets Sold			134
Property And Equipment [Member]
Asset Impairment Charges			$ 181,800,000
Property And Equipment [Member] | Ferrellgas, L.P. [Member]
Asset Impairment Charges			181,800,000
Jamex Marketing, LLC [Member]
Accounts Receivable, Related Parties, Noncurrent	39,800,000	$ 32,500,000	39,800,000
Jamex Marketing, LLC [Member] | Ferrellgas, L.P. [Member]
Accounts Receivable, Related Parties, Noncurrent	$ 39,800,000	$ 32,500,000	$ 39,800,000