Derivative Instruments and Hedging Activities (Changes in Derivative Value Effect on Other Comprehensive Income Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Jul. 31, 2017	Jul. 31, 2016
Beginning balance	$ 17,672		$ 17,672		$ 14,601
Change in value of risk management derivatives	(159)	$ (6,496)	23,362	$ 13,904
Reclassification of gains and losses on commodity hedges to cost of product sold - propane and other gas liquids sales	(6,568)	(1,933)	(20,260)	2,819
Ending balance	17,672		17,672
Ferrellgas, L.P. [Member]
Beginning balance	17,866		17,866		14,764
Change in value of risk management derivatives	(159)	(6,496)	23,362	13,904
Reclassification of gains and losses on commodity hedges to cost of product sold - propane and other gas liquids sales	(6,568)	(1,933)	(20,260)	2,819
Ending balance	17,866		17,866
Propane commodity derivatives [Member]
Change in value of risk management derivatives	(169)	(6,642)	23,114	12,930
Reclassification of gains and losses on commodity hedges to cost of product sold - propane and other gas liquids sales			(20,646)	1,112
Propane commodity derivatives [Member] \| Ferrellgas, L.P. [Member]
Change in value of risk management derivatives	(169)	(6,642)	23,114	12,930
Reclassification of gains and losses on commodity hedges to cost of product sold - propane and other gas liquids sales			(20,646)	1,112
Interest Rate Swap [Member]
Change in value of risk management derivatives	10	146	248	974
Derivative, Net Hedge Ineffectiveness Gain (Loss)			386	1,707
Interest Rate Swap [Member] \| Ferrellgas, L.P. [Member]
Change in value of risk management derivatives	10	146	248	974
Derivative, Net Hedge Ineffectiveness Gain (Loss)			386	1,707
Derivative [Member]
Beginning balance	17,750	6,908	17,750	6,908	14,648	$ (9,815)
Ending balance	17,750	6,908	17,750	6,908
Derivative [Member] \| Ferrellgas, L.P. [Member]
Beginning balance	17,750	6,908	17,750	6,908	$ 14,648	$ (9,815)
Ending balance	$ 17,750	$ 6,908	$ 17,750	$ 6,908

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount of gain (loss) from the ineffectiveness of the hedge.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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