Partners' Deficit - Paid Distributions (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Limited Partners' Capital Account [Line Items]
Distributions paid	$ 158	$ 10,229	$ 39,970
Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	0	9,814	39,254
Parent [Member] | Ferrell Companies [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		2,253	9,012
Parent [Member] | FCI Trading Corp. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		20	80
Parent [Member] | Ferrell Propane, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		5	20
Parent [Member] | James E. Ferrell [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		476	1,904
Parent [Member] | Ferrellgas Inc., General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		98	392
Common Unitholders [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		9,716	38,862
Public Common Unitholders [Member] | Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		6,962	27,846
General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		98	392
Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	15,654	41,121	70,962
Ferrellgas, L.P. [Member] | Ferrellgas Inc., General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	158	415	716
Ferrellgas, L.P. [Member] | Ferrellgas Partners LP [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	15,496	40,706	70,246
Ferrellgas, L.P. [Member] | Common Unitholders [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	15,496	40,706	70,246
Ferrellgas, L.P. [Member] | General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	$ 158	$ 415	$ 716