Partners' Deficit - Narrative (Details) - shares	6 Months Ended
	Jan. 31, 2019	Jul. 31, 2018
Capital Unit [Line Items]
Common unitholders, units outstanding	97,152,665	97,152,665
Ferrell Companies [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Limited partner ownership interest	23.00%
Ferrell Companies [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	22,529,361	22,529,361
Ferrell Companies [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Limited partner ownership interest	23.40%
Ferrell Companies [Member] | FCI Trading Corp. [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	195,686
Ferrell Companies [Member] | Ferrell Propane, Inc. [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	51,204
James E. Ferrell [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	4,763,475	4,763,475
James E. Ferrell [Member] | JEF Capital Management [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	4,758,859
James E. Ferrell [Member] | Ferrell Resources Holdings, Inc. [Member] | Ferrellgas Partners LP [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding	4,616