Partners' Deficit - Paid Distributions (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2016	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Limited Partners' Capital Account [Line Items]
Distributions paid		$ 10,229	$ 39,970	$ 80,783
Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	$ 15,900	41,121	70,962	119,879
Ferrellgas Inc., General Partner [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		415	716	1,050
Ferrellgas Partners LP [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		40,706	70,246	102,978
Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		9,814	39,254	79,733
Parent [Member] | Ferrell Companies [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		2,253	9,012	18,305
Parent [Member] | FCI Trading Corp. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		20	80	160
Parent [Member] | Ferrell Propane, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		5	20	41
Parent [Member] | James E. Ferrell [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		476	1,904	3,869
Parent [Member] | Ferrellgas Inc., General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		98	392	797
Common Unitholders [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		9,716	38,862	78,936
Common Unitholders [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		40,706	70,246	118,829
Public Common Unitholders [Member] | Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		6,962	27,846	56,561
General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		98	392	797
General Partner [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		$ 415	$ 716	$ 1,050