Derivative Instruments and Hedging Activities (Fair Value of Financial Derivatives Balance Sheet Locations) (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Jul. 31, 2017
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	$ 19,750	$ 16,212
Interest rate swap assets	41	583
Derivative assets, fair value	19,791	16,795
Propane commodity derivative liabilities	2,239	1,258
Interest rate swap liabilities	3,222	707
Derivative liabilities, fair value	5,461	1,965
Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	19,750	16,212
Interest rate swap assets	41	583
Derivative assets, fair value	19,791	16,795
Propane commodity derivative liabilities	2,239	1,258
Interest rate swap liabilities	3,222	707
Derivative liabilities, fair value	5,461	1,965
Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	14,449	11,061
Interest rate swap assets	41	583
Prepaid Expenses and Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	14,449	11,061
Interest rate swap assets	41	583
Other assets, net [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	5,301	4,413
Interest rate swap assets	0	0
Other assets, net [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative assets	5,301	4,413
Interest rate swap assets	0	0
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative liabilities	2,207	415
Interest rate swap liabilities	738	595
Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative liabilities	2,207	415
Interest rate swap liabilities	738	595
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative liabilities	32	15
Interest rate swap liabilities	2,484	112
Other Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Propane commodity derivative liabilities	32	15
Interest rate swap liabilities	$ 2,484	112
Midstream - Crude Oil Logistics [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net		738
Midstream - Crude Oil Logistics [Member] | Prepaid Expenses and Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Other Derivatives Not Designated as Hedging Instruments at Fair Value, Net		738
Midstream - Crude Oil Logistics [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value		828
Midstream - Crude Oil Logistics [Member] | Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value		$ 828