Derivative Instruments and Hedging Activities (Fair Value of Financial Derivatives Balance Sheet Locations) (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	$ 1,049	$ 7,637
Interest Rate Derivative Assets, at Fair Value	7,784
Derivative Asset, Fair Value, Gross Asset	8,833	7,637
Derivatives - Price risk management liabilities	12,069	2,476
Interest Rate Derivative Liabilities, at Fair Value	1,778
Derivative Liability, Fair Value, Gross Liability	13,847	2,476
Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	1,049	7,637
Interest Rate Derivative Assets, at Fair Value	7,784
Derivative Asset, Fair Value, Gross Asset	8,833	7,637
Derivatives - Price risk management liabilities	12,069	2,476
Interest Rate Derivative Liabilities, at Fair Value	1,778
Derivative Liability, Fair Value, Gross Liability	13,847	2,476
Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	1,049	7,637
Interest Rate Derivative Assets, at Fair Value	3,346
Prepaid Expenses And Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	1,049	7,637
Interest Rate Derivative Assets, at Fair Value	3,346
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	12,069	2,476
Interest Rate Derivative Liabilities, at Fair Value	0
Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	12,069	2,476
Interest Rate Derivative Liabilities, at Fair Value	0
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	4,438
Other Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	4,438
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	1,778
Other Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	$ 1,778