Derivative Instruments and Hedging Activities (Changes in Derivative Value Effect on Other Comprehensive Income Loss) (Details) (USD $) In Thousands, unless otherwise specified					3 Months Ended
	Oct. 31, 2012	Jul. 31, 2012	Oct. 31, 2012 Ferrellgas, L.P. [Member]	Jul. 31, 2012 Ferrellgas, L.P. [Member]	Oct. 31, 2012 Derivative [Member]	Oct. 31, 2011 Derivative [Member]	Oct. 31, 2012 Derivative [Member] Ferrellgas, L.P. [Member]	Oct. 31, 2011 Derivative [Member] Ferrellgas, L.P. [Member]
Beginning balance	$ (2,795)	$ (13,159)	$ (2,811)	$ (13,280)	$ (12,799)	$ 5,161	$ (12,799)	$ 5,161
Change in value on risk management commodity derivatives					6,526	(2,528)	6,526	(2,528)
Reclassification of gains (losses) from AOCI(L) to Cost of product sold - propane and other gas liquids					4,191	(1,879)	4,191	(1,879)
Change in value on risk management interest rate derivatives					(250)		(250)
Ending balance	$ (2,795)	$ (13,159)	$ (2,811)	$ (13,280)	$ (2,332)	$ 754	$ (2,332)	$ 754