Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities (Derivatives Not Designated as Hedging Effect on Earnings) (Details) - Operating Expense [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Propane and related equipment sales [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ (393)		$ 1,123
Propane and related equipment sales [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(393)		1,123
Midstream - Crude Oil Logistics [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 0	1,464	$ (3,470)	(784)
Midstream - Crude Oil Logistics [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 0	$ 1,464	$ (3,470)	$ (784)