Accounts And Notes Receivable, Net And Accounts Receivable Securitization - Additional information (Details) - USD ($)	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017	May 13, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	$ 106,145,000	$ 120,079,000
Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	106,145,000	120,079,000
Cash collected for purchase of interest in accounts receivable	0	0	$ 0
Capacity to receive additional proceeds	23,100,000
Trade Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	106,100,000	120,100,000
Cash collected for purchase of interest in accounts receivable	62,000,000	58,000,000
Available proceeds from additional trade accounts receivable	0	0
Trade Accounts Receivable | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	106,100,000	120,100,000
Cash collected for purchase of interest in accounts receivable	62,000,000	58,000,000
Available proceeds from additional trade accounts receivable	0	0
Accounts Receivable Securitization Facility [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateralized notes payable	$ 62,000,000	$ 58,000,000
Margin added to variable rate (as a percent)	2.00%
Secured line of credit facility	$ 250,000,000			$ 225,000,000
Weighted average discount rate to value the retained interest in the transferred receivables	5.50%	5.20%
Accounts Receivable Securitization Facility [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateralized notes payable	$ 62,000,000	$ 58,000,000
Margin added to variable rate (as a percent)	2.00%
Secured line of credit facility	$ 250,000,000			$ 225,000,000
Weighted average discount rate to value the retained interest in the transferred receivables	5.50%	5.20%
Letter of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured line of credit facility	$ 50,000,000
Letter of Credit [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured line of credit facility	$ 50,000,000