Derivative Instruments and Hedging Activities (Cash Flow Derivative Value Recorded in OCI and reclassified to Earnings) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Amount of gain (loss) recognized in AOCI(L) on derivative	$ (25,068)	$ 22,676
Amount of gain (loss) reclassified from AOCI(L)	7,108	(17,358)
Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(25,068)	22,676
Amount of gain (loss) reclassified from AOCI(L)	7,108	(17,358)
Interest Rate Swap [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(1,778)
Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(1,778)
Commodity Derivatives Propane [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(23,290)	22,676	12,063
Reclassification of gains (losses) from AOCI(L) to Cost of product sold - propane and other gas liquids	7,108	(17,358)	(11,231)
Commodity Derivatives Propane [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI(L) on derivative	(23,290)	22,676	12,063
Reclassification of gains (losses) from AOCI(L) to Cost of product sold - propane and other gas liquids	$ 7,108	$ (17,358)	$ (11,231)