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, 2014	Oct. 31, 2013
Amount of gain (loss) recognized in AOCI	$ (13,897)	$ 10,604
Amount of gain (loss) reclassified from AOCI into income	(1,128)	929
Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	(13,897)	10,604
Amount of gain (loss) reclassified from AOCI into income	1,128	929
Propane commodity derivatives [Member]
Amount of gain (loss) recognized in AOCI	(12,758)	11,617
Amount of gain (loss) reclassified from AOCI into income	1,128	929
Propane commodity derivatives [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	(12,758)	11,617
Amount of gain (loss) reclassified from AOCI into income	1,128	929
Interest Rate Swap [Member]
Amount of gain (loss) recognized in AOCI	(1,139)	(1,013)
Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) recognized in AOCI	(1,139)	(1,013)
Cost of Product Sold [Member] | Propane commodity derivatives [Member]
Amount of gain (loss) reclassified from AOCI into income	(1,128)	929
Cost of Product Sold [Member] | Propane commodity derivatives [Member] | Ferrellgas, L.P. [Member]
Amount of gain (loss) reclassified from AOCI into income	1,128	929
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