Derivative Instruments and Hedging Activities - Balance Sheet (Details) - USD ($)	6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jul. 31, 2019
Derivatives, Fair Value [Line Items]
Gain (loss) recognized due to ineffectiveness	$ 0
Gain (loss) recognized due to ineffectiveness, pre-adoption		$ 0
Derivative Asset, Fair Value, Gross Asset	253,000		$ 1,259,000
Derivative Liability, Fair Value, Gross Liability	23,602,000		16,015,000
Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Gain (loss) recognized due to ineffectiveness	0
Gain (loss) recognized due to ineffectiveness, pre-adoption		$ 0
Derivative Asset, Fair Value, Gross Asset	253,000		1,259,000
Derivative Liability, Fair Value, Gross Liability	23,602,000		16,015,000
Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	253,000		910,000
Prepaid Expenses and Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets	253,000		910,000
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	22,861,000		14,198,000
Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	22,861,000		14,198,000
Other Assets, Net [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets			349,000
Other Assets, Net [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap assets			349,000
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	741,000		1,817,000
Other Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Commodity derivatives propane swap liabilities	$ 741,000		$ 1,817,000