Supplemental Financial Statement Information (Narrative) (Details)	3 Months Ended
	Oct. 31, 2017 gal
Maximum term of supply procurement contracts	36 months
Net procurement of fixed priced propane in gallons	119,300,000
Ferrellgas, L.P. [Member]
Maximum term of supply procurement contracts	36 months
Net procurement of fixed priced propane in gallons	119,300,000