Derivatives (Assets And Liabilities Measured At Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2011	Jul. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Price risk management assets	$ 2,044	$ 7,637
Price risk management liabilities	1,290	2,476
Ferrellgas, L.P. And Subsidiaries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Price risk management assets	2,044	7,637
Price risk management liabilities	1,290	2,476
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Price risk management assets	2,044	7,637
Price risk management liabilities	1,290	2,476
Level 2 [Member] | Ferrellgas, L.P. And Subsidiaries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Price risk management assets	2,044	7,637
Price risk management liabilities	$ 1,290	$ 2,476