Derivatives (Fair Value Of The Financial Derivative Instruments) (Details) (USD $) In Thousands	Jul. 31, 2011	Jul. 31, 2010
Ferrellgas, L.P. And Subsidiaries [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives - Price risk management assets	$ 7,637	$ 1,882
Prepaid Expenses And Other Current Assets [Member]
Derivatives - Price risk management assets	7,637	1,882
Ferrellgas, L.P. And Subsidiaries [Member] | Other Current Liabilities [Member]
Derivatives - Price risk management liabilities	2,476	2,039
Other Current Liabilities [Member]
Derivatives - Price risk management liabilities	$ 2,476	$ 2,039