Supplemental Financial Statement Information - Property, Plant And Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,255,518	$ 1,201,117
Less: accumulated depreciation	658,795	643,394
Property, plant and equipment, net	596,723	557,723
Depreciation	60,700	67,100	$ 68,100
Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,255,518	1,201,117
Less: accumulated depreciation	658,795	643,394
Property, plant and equipment, net	596,723	557,723
Depreciation	$ 60,700	67,100	$ 68,100
Land [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	Indefinite
Property, plant and equipment, gross	$ 35,165	33,719
Land [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	35,165	33,719
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	14,149	13,361
Land Improvements [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 14,149	13,361
Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Property, plant and equipment, gross	$ 86,444	71,612
Buildings And Improvements [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Property, plant and equipment, gross	$ 86,444	71,612
Vehicles, Including Transport Trailers [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	111,283	85,893
Vehicles, Including Transport Trailers [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	111,283	85,893
Bulk Equipment And District Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	109,751	103,627
Bulk Equipment And District Facilities [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	109,751	103,627
Tanks, Cylinders And Customer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	779,827	769,165
Tanks, Cylinders And Customer Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	779,827	769,165
Computer And Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	111,838	109,346
Computer And Office Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	111,838	109,346
Construction In Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	7,061	14,394
Construction In Progress [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 7,061	$ 14,394
Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Land Improvements [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Vehicles, Including Transport Trailers [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Minimum [Member] | Vehicles, Including Transport Trailers [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	8 years
Minimum [Member] | Bulk Equipment And District Facilities [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum [Member] | Bulk Equipment And District Facilities [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Minimum [Member] | Tanks, Cylinders And Customer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Tanks, Cylinders And Customer Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Computer And Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Minimum [Member] | Computer And Office Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	2 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum [Member] | Land Improvements [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum [Member] | Vehicles, Including Transport Trailers [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum [Member] | Vehicles, Including Transport Trailers [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 years
Maximum [Member] | Bulk Equipment And District Facilities [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Bulk Equipment And District Facilities [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Tanks, Cylinders And Customer Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Tanks, Cylinders And Customer Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	30 years
Maximum [Member] | Computer And Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Maximum [Member] | Computer And Office Equipment [Member] | Ferrellgas, L.P. [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years