Derivative Instruments and Hedging Activities (Cash Flow Derivative Value Recorded in OCI and reclassified to Earnings) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2012	Oct. 31, 2011
Amount of gain (loss) recognized in AOCI(L) on derivative	$ 6,276	$ (2,528)
Amount of gain (loss) reclassified from AOCI(L)	(4,191)	1,879
Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	6,276	(2,528)
Amount of gain (loss) reclassified from AOCI(L)	(4,191)	1,879
Commodity Derivatives Propane [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	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
Commodity Derivatives Propane [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	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
Interest Rate Swap [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(250)
Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	$ (250)