Derivative Instruments and Hedging Activities (Fair Value of Financial Derivatives Balance Sheet Locations) (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013	Jul. 31, 2012
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	$ 2,133	$ 1,049
Interest Rate Derivative Assets, at Fair Value	8,008	7,784
Derivative Asset, Fair Value, Gross Asset	10,141	8,833
Derivatives - Price risk management liabilities	3,613	12,069
Interest Rate Derivative Liabilities, at Fair Value	2,622	1,778
Derivative Liability, Fair Value, Gross Liability	6,235	13,847
Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	2,133	1,049
Interest Rate Derivative Assets, at Fair Value	8,008	7,784
Derivative Asset, Fair Value, Gross Asset	10,141	8,833
Derivatives - Price risk management liabilities	3,613	12,069
Interest Rate Derivative Liabilities, at Fair Value	2,622	1,778
Derivative Liability, Fair Value, Gross Liability	6,235	13,847
Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	627	1,049
Interest Rate Derivative Assets, at Fair Value	3,324	3,346
Prepaid Expenses And Other Current Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	627	1,049
Interest Rate Derivative Assets, at Fair Value	3,324	3,346
Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	3,613	12,069
Interest Rate Derivative Liabilities, at Fair Value	0	0
Other Current Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	3,613	12,069
Interest Rate Derivative Liabilities, at Fair Value	0	0
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	1,506
Interest Rate Derivative Assets, at Fair Value	4,684	4,438
Other Assets [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management assets	1,506
Interest Rate Derivative Assets, at Fair Value	4,684	4,438
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	0
Interest Rate Derivative Liabilities, at Fair Value	2,622	1,778
Other Liabilities [Member] | Ferrellgas, L.P. [Member]
Derivatives, Fair Value [Line Items]
Derivatives - Price risk management liabilities	0
Interest Rate Derivative Liabilities, at Fair Value	$ 2,622	$ 1,778