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		6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Propane and related equipment sales [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ 489		$ 1,516
Propane and related equipment sales [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		489		1,516
Midstream - Crude Oil Logistics [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (2,080)	(1,007)	$ (3,470)	(2,248)
Midstream - Crude Oil Logistics [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (2,080)	$ (1,007)	$ (3,470)	$ (2,248)