Derivative Instruments and Hedging Activities (Cash Flow Hedge Derivative Effect on Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2013	Oct. 31, 2012
Amount of gain (loss) recognized in AOCI	$ 10,604	$ 6,276
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	10,604	6,276
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Propane commodity derivatives [Member]
Amount of gain (loss) recognized in AOCI	11,617	6,526
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Propane commodity derivatives [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	11,617	6,526
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Interest Rate Swap [Member]
Amount of gain (loss) recognized in AOCI	(1,013)	(250)
Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	(1,013)	(250)
Cost of Sales [Member] | Propane commodity derivatives [Member]
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Cost of Sales [Member] | Propane commodity derivatives [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) reclassified from AOCI into income	929	(4,191)
Interest Expense [Member] | Interest Rate Swap [Member]
Amount of gain (loss) reclassified from AOCI into income	0	0
Interest Expense [Member] | Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) reclassified from AOCI into income	$ 0	$ 0