Accounts And Notes Receivable, Net (Narrative) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jan. 31, 2012	Jul. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable securitization program, maximum capacity	$ 225,000,000
Accounts receivable from securitization maturity period	Jan. 19, 2017
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	205,000,000	61,000,000
Available proceeds from additional trade accounts receivable		3,000,000
Pledged trade receivable as collateral against collateralized notes payable	293,163,000	112,509,000
Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable securitization program, maximum capacity	225,000,000
Accounts receivable from securitization maturity period	Jan. 19, 2017
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	205,000,000	61,000,000
Available proceeds from additional trade accounts receivable		3,000,000
Pledged trade receivable as collateral against collateralized notes payable	293,163,000	112,509,000
Accounts Receivable Securitization [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average discount rate to value the retained interest in the transferred receivables	2.80%	3.60%
Accounts Receivable Securitization [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average discount rate to value the retained interest in the transferred receivables	2.80%	3.60%
Commercial Paper [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pledged trade receivable as collateral against collateralized notes payable	293,200,000
Note payable to Ferrellgas, L.P.	205,000,000
Commercial Paper [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pledged trade receivable as collateral against collateralized notes payable	293,200,000
Note payable to Ferrellgas, L.P.	205,000,000
Operating Partnership's Previous 364-Day Facility [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable from securitization maturity period	Apr. 04, 2013
Operating Partnership's Previous 364-Day Facility [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable from securitization maturity period	Apr. 04, 2013
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in interest rate from previous facility	1.45%
Maximum [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in interest rate from previous facility	1.45%
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in interest rate from previous facility	1.20%
Minimum [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in interest rate from previous facility	1.20%
January, February, March, and December [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	225,000,000
January, February, March, and December [Member] | Maximum [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	225,000,000
April And May [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	175,000,000
April And May [Member] | Maximum [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	175,000,000
All Other Months [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	145,000,000
All Other Months [Member] | Maximum [Member] | Ferrellgas, L.P. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds to Ferrellgas from securitizing receivables to a commercial paper conduit	$ 145,000,000