Derivative Instruments and Hedging Activities - Effect on Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Derivative [Line Items]
Swap Termination Payment			$ 4,200
Interest expense	$ (192,962)	$ (177,619)	(168,467)
Interest Rate Swap [Member]
Derivative [Line Items]
Amount of Gain Recognized			266
Interest expense			(6,825)
Ferrellgas, L.P. [Member]
Derivative [Line Items]
Swap Termination Payment			4,200
Interest expense	$ (159,889)	$ (142,635)	(133,946)
Ferrellgas, L.P. [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Amount of Gain Recognized			266
Interest expense			$ (6,825)