Accounts And Notes Receivable, Net And Accounts Receivable Securitization (Narrative) (Details) - USD ($)	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	$ 109,407,000	$ 106,464,000
Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable pledged as collateral	109,407,000	106,464,000
Accounts Receivable Securitization [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable securitization program, maximum capacity	$ 225,000,000
Accounts receivable securitization program, maturity date	Jul. 29, 2019
Accounts receivable pledged as collateral	$ 109,400,000	106,500,000
Available proceeds from additional trade accounts receivable	$ 0	$ 0
Weighted average discount rate to value the retained interest in the transferred receivables	4.00%	3.00%
Note payable	$ 69,000,000	$ 64,000,000
Proceeds from Accounts Receivable Securitization	69,000,000	64,000,000
Accounts Receivable Securitization [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable securitization program, maximum capacity	$ 225,000,000.0
Accounts receivable securitization program, maturity date	Jul. 29, 2019
Accounts receivable pledged as collateral	$ 109,400,000	106,500,000
Available proceeds from additional trade accounts receivable	$ 0	$ 0
Weighted average discount rate to value the retained interest in the transferred receivables	4.00%	3.00%
Note payable	$ 69,000,000	$ 64,000,000
Proceeds from Accounts Receivable Securitization	69,000,000	$ 64,000,000
January, February, March, And December [Member] | Maximum [Member] | Accounts Receivable Securitization [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	225,000,000
January, February, March, And December [Member] | Maximum [Member] | Accounts Receivable Securitization [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	225,000,000.0
April And May [Member] | Maximum [Member] | Accounts Receivable Securitization [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	175,000,000
April And May [Member] | Maximum [Member] | Accounts Receivable Securitization [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	175,000,000.0
All Other Months [Member] | Maximum [Member] | Accounts Receivable Securitization [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	145,000,000
All Other Months [Member] | Maximum [Member] | Accounts Receivable Securitization [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from Accounts Receivable Securitization	$ 145,000,000.0