Derivative Instruments and Hedging Activities - Balance Sheet (Details) - USD ($)	9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Jul. 31, 2018
Derivatives, Fair Value [Line Items]
Gain (loss) recognized due to ineffectiveness	$ 0	$ 0
Derivative Asset, Fair Value, Gross Asset	5,489,000		$ 22,470,000
Derivative Liability, Fair Value, Gross Liability	6,502,000		1,910,000
Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Gain (loss) recognized due to ineffectiveness	0	$ 0
Derivative Asset, Fair Value, Gross Asset	5,489,000		22,470,000
Derivative Liability, Fair Value, Gross Liability	6,502,000		1,910,000
Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	5,049,000		17,123,000
Prepaid Expenses and Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	5,049,000		17,123,000
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	5,726,000		1,832,000
Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	5,726,000		1,832,000
Other Assets, Net [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	440,000		5,347,000
Other Assets, Net [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	440,000		5,347,000
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	776,000		78,000
Other Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	$ 776,000		$ 78,000