Fair Value Measurements (Assets And Liabilities Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Jul. 31, 2016
Interest rate swap assets	$ 583	$ 5,830
Commodity derivatives propane swap assets	16,212	8,241
Interest rate swap liabilities	(707)	(3,553)
Commodity derivatives propane swap liabilities	(1,258)	(17,689)
Ferrellgas, L.P. [Member]
Interest rate swap assets	583	5,830
Commodity derivatives propane swap assets	16,212	8,241
Interest rate swap liabilities	(707)	(3,553)
Commodity derivatives propane swap liabilities	(1,258)	(17,689)
Fair Value, Inputs, Level 1 [Member]
Interest rate swap assets	0	0
Commodity derivatives propane swap assets	0	0
Interest rate swap liabilities	0	0
Commodity derivatives propane swap liabilities	0	0
Fair Value, Inputs, Level 1 [Member] | Ferrellgas, L.P. [Member]
Interest rate swap assets	0	0
Commodity derivatives propane swap assets	0	0
Interest rate swap liabilities	0	0
Commodity derivatives propane swap liabilities	0	0
Level 2 [Member]
Interest rate swap assets	583	5,830
Commodity derivatives propane swap assets	16,212	8,241
Interest rate swap liabilities	(707)	(3,553)
Commodity derivatives propane swap liabilities	(1,258)	(17,689)
Level 2 [Member] | Ferrellgas, L.P. [Member]
Interest rate swap assets	583	5,830
Commodity derivatives propane swap assets	16,212	8,241
Interest rate swap liabilities	(707)	(3,553)
Commodity derivatives propane swap liabilities	(1,258)	(17,689)
Fair Value, Inputs, Level 3 [Member]
Interest rate swap assets	0	0
Commodity derivatives propane swap assets	0	0
Interest rate swap liabilities	0	0
Commodity derivatives propane swap liabilities	0	0
Fair Value, Inputs, Level 3 [Member] | Ferrellgas, L.P. [Member]
Interest rate swap assets	0	0
Commodity derivatives propane swap assets	0	0
Interest rate swap liabilities	0	0
Commodity derivatives propane swap liabilities	$ 0	$ 0