Derivative Instruments and Hedging Activities (Changes in Derivative Value Effect on Other Comprehensive Income Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Beginning balance	$ (10,468)
Ending balance	14,601	$ (10,468)
Derivative, Net Hedge Ineffectiveness Gain (Loss)	2,092	2,864	$ 199
Ferrellgas, L.P. [Member]
Beginning balance	(10,560)
Ending balance	14,764	(10,560)
Derivative, Net Hedge Ineffectiveness Gain (Loss)	2,092	2,864	199
Commodity Derivatives Propane [Member]
Change in value on risk management derivatives	21,659	4,409	(70,291)
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	(154)	24,438	28,059
Commodity Derivatives Propane [Member] | Ferrellgas, L.P. [Member]
Change in value on risk management derivatives	21,659	4,409	(70,291)
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	(154)	24,438	28,059
Interest Rate Swap [Member]
Change in value on risk management derivatives	866	(2,620)	(3,356)
Interest Rate Swap [Member] | Ferrellgas, L.P. [Member]
Change in value on risk management derivatives	866	(2,620)	(3,356)
Derivative [Member]
Beginning balance	(9,815)	(38,906)	6,483
Change in value on risk management derivatives	22,525	1,789	(73,647)
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	1,938	27,302	28,059
Ending balance	14,648	(9,815)	(38,906)
Derivative [Member] | Ferrellgas, L.P. [Member]
Beginning balance	(9,815)	(38,906)	6,483
Change in value on risk management derivatives	22,525	1,789	(73,647)
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	1,938	27,302	28,059
Ending balance	14,648	(9,815)	(38,906)
Cost of Sales [Member] | Commodity Derivatives Propane [Member]
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	(154)	24,438	28,059
Cost of Sales [Member] | Commodity Derivatives Propane [Member] | Ferrellgas, L.P. [Member]
Reclassification of gains and losses of commodity hedges to cost of product sold - propane and other gas liquids sales	(154)	24,438	28,059
Cost of Sales [Member] | Midstream - Crude Oil Logistics [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(425)	1,084
Cost of Sales [Member] | Midstream - Crude Oil Logistics [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(425)	1,084
Operating Expense [Member] | Propane and related equipment sales [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1,090	(4,351)	(2,412)
Operating Expense [Member] | Propane and related equipment sales [Member] | Ferrellgas, L.P. [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 1,090	$ (4,351)	$ (2,412)