Derivative Instruments and Hedging Activities (Fair Value Hedge Derivative Effect on Earnings) (Details) - Interest Rate Swap [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Derivative, Gain (Loss) on Derivative, Net	$ 40	$ 323	$ 266	$ 1,071
Interest expense recognized on fixed-rate debt	(2,275)	(2,275)	(6,825)	(6,825)
Ferrellgas, L.P. [Member]
Derivative, Gain (Loss) on Derivative, Net	40	323	266	1,071
Interest expense recognized on fixed-rate debt	$ (2,275)	$ (2,275)	$ (6,825)	$ (6,825)