Derivative Instruments and Hedging Activities (Narrative) (Details) MMBbls in Millions	6 Months Ended
	Jan. 31, 2018 USD ($) MMBbls	Jan. 31, 2017 USD ($)
Reclassification of net gain to earnings during next 12 months	$ 16,800,000
Description of Reclassification of Cash Flow Hedge Gain (Loss)	0
Number of barrels of propane covered by cash flow hedges | MMBbls	2.6
Derivative amount of credit risk	$ 7,500,000
Derivative net liability position aggregate fair value	0
Gain or loss in earnings related to hedge ineffectiveness	0	$ 0
Reclassifications to earnings resulting from discontinuance of cash flow hedges	0	0
Ferrellgas, L.P. [Member]
Reclassification of net gain to earnings during next 12 months	$ 16,800,000
Description of Reclassification of Cash Flow Hedge Gain (Loss)	0
Number of barrels of propane covered by cash flow hedges | MMBbls	2.6
Derivative amount of credit risk	$ 7,500,000
Derivative net liability position aggregate fair value	0
Gain or loss in earnings related to hedge ineffectiveness	0	0
Reclassifications to earnings resulting from discontinuance of cash flow hedges	$ 0	$ 0