Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities (Schedule of Derivative Collateral) (Details) - USD ($) $ in Thousands	Jul. 31, 2017	Jul. 31, 2016
Derivative Asset, Fair Value of Collateral	$ 3,409	$ 9,527
Derivative Liability, Fair Value of Collateral	10,802	0
Prepaid Expenses and Other Current Assets [Member]
Derivative Asset, Fair Value of Collateral	1,778	8,252
Other Current Liabilities [Member]
Derivative Liability, Fair Value of Collateral	7,729	0
Other Assets, Net [Member]
Derivative Asset, Fair Value of Collateral	1,631	1,275
Other Liabilities [Member]
Derivative Liability, Fair Value of Collateral	3,073	0
Ferrellgas, L.P. [Member]
Derivative Asset, Fair Value of Collateral	3,409	9,527
Derivative Liability, Fair Value of Collateral	10,802	0
Ferrellgas, L.P. [Member] | Prepaid Expenses and Other Current Assets [Member]
Derivative Asset, Fair Value of Collateral	1,778	8,252
Ferrellgas, L.P. [Member] | Other Current Liabilities [Member]
Derivative Liability, Fair Value of Collateral	7,729	0
Ferrellgas, L.P. [Member] | Other Assets, Net [Member]
Derivative Asset, Fair Value of Collateral	1,631	1,275
Ferrellgas, L.P. [Member] | Other Liabilities [Member]
Derivative Liability, Fair Value of Collateral	$ 3,073	$ 0