Partners' Deficit - Paid Distributions (Details) - USD ($) $ in Thousands	3 Months Ended					9 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Apr. 30, 2019	Apr. 30, 2018
Limited Partners' Capital Account [Line Items]
Distributions paid	$ 157	$ 9,915	$ 9,915	$ 10,071	$ 9,913
Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	15,553	10,015	10,115	25,467	9,913	$ 25,568	$ 45,495
Ferrellgas Inc., General Partner [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			102			258	459
Ferrellgas Partners LP [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			10,013			25,310	45,036
Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		9,814	9,813	9,814	9,813	9,814	29,440
Parent [Member] | Ferrell Companies [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			2,253			2,253	6,759
Parent [Member] | FCI Trading Corp. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			20			20	60
Parent [Member] | Ferrell Propane, Inc. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			5			5	15
Parent [Member] | James E. Ferrell [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			476			476	1,428
Parent [Member] | Ferrellgas Inc., General Partner [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			98			98	294
Common Unitholders [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid		9,716	9,715	9,716	9,715
Common Unitholders [Member] | Ferrellgas, L.P. [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid	$ 15,396	$ 9,914	10,013	$ 25,210	$ 9,813
Public Common Unitholders [Member] | Parent [Member]
Limited Partners' Capital Account [Line Items]
Distributions paid			$ 6,961			$ 6,962	$ 20,884