The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

+ Details

Name:	us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeNonmonetaryNotionalAmountVolume
Namespace Prefix:	us-gaap_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of net gain (loss) reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

+ Details

Name:	us-gaap_GainLossOnDiscontinuationOfCashFlowHedgeDueToForecastedTransactionProbableOfNotOccurringNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, after tax and before reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount after tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph c
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41638-113959

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL34724391-108580

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109978405&loc=d3e80720-113993

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

+ Details

Name:	us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of partners' capital (deficit), including portions attributable to both the parent and noncontrolling interests. Excludes temporary equity and is sometimes called permanent equity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70478-108055

+ Details

Name:	us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_PartnerCapitalComponentsAxis=us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PartnerCapitalComponentsAxis=us-gaap_AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=fgp_FerrellgasLPMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_EnergyRelatedDerivativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Instruments and Hedging Activities - AOCI Rollforward (Details) gal in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2020 USD ($) gal	Jan. 31, 2019 USD ($)
Derivative [Line Items]
Partners' capital balance, beginning	$ (1,191,384,000)	$ (1,111,739,000)	$ (1,138,938,000)	$ (1,034,477,000)
Change in value of derivative	(11,212,000)		(24,839,000)
Change in value of derivative, pre-adoption		(21,080,000)		(29,234,000)
Reclassification of (gains) losses on derivatives to earnings, net	8,766,000		16,245,000
Reclassification of (gains) losses on derivatives to earnings, net, pre-adoption		3,807,000		(626,000)
Partners' capital balance, ending	(1,144,675,000)	(1,083,350,000)	(1,144,675,000)	(1,083,350,000)
Reclassification of net losses to earnings during next 12 months			22,600,000
Gain (loss) on discontinuation of cash flow hedge due to forecasted transaction probable of not occurring, net			$ 0	0
Number of barrels of propane covered by cash flow hedges \| gal			3.4
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Derivative [Line Items]
Partners' capital balance, beginning			$ (14,756,000)
Partners' capital balance, ending	(23,350,000)		(23,350,000)
Accumulated Net Gain (Loss) from Cash Flow Hedges, pre-adoption
Derivative [Line Items]
Partners' capital balance, beginning				20,560,000
Partners' capital balance, ending		(9,300,000)		(9,300,000)
Ferrellgas, L.P. [Member]
Derivative [Line Items]
Partners' capital balance, beginning	(824,130,000)	(748,746,000)	(780,403,000)	(680,078,000)
Change in value of derivative	(11,212,000)		(24,839,000)
Change in value of derivative, pre-adoption		(21,080,000)		(29,234,000)
Reclassification of (gains) losses on derivatives to earnings, net	8,766,000		16,245,000
Reclassification of (gains) losses on derivatives to earnings, net, pre-adoption		3,807,000		(626,000)
Partners' capital balance, ending	(783,852,000)	(727,011,000)	(783,852,000)	(727,011,000)
Reclassification of net losses to earnings during next 12 months			22,600,000
Gain (loss) on discontinuation of cash flow hedge due to forecasted transaction probable of not occurring, net			$ 0	0
Number of barrels of propane covered by cash flow hedges \| gal			3.4
Ferrellgas, L.P. [Member] \| Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Derivative [Line Items]
Partners' capital balance, beginning			$ (14,756,000)
Partners' capital balance, ending	$ (23,350,000)		(23,350,000)
Ferrellgas, L.P. [Member] \| Accumulated Net Gain (Loss) from Cash Flow Hedges, pre-adoption
Derivative [Line Items]
Partners' capital balance, beginning				20,560,000
Partners' capital balance, ending		$ (9,300,000)		(9,300,000)
Commodity Derivatives Propane [Member] \| Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Derivative [Line Items]
Change in value of derivative			(24,839,000)
Reclassification of (gains) losses on derivatives to earnings, net			16,245,000
Commodity Derivatives Propane [Member] \| Accumulated Net Gain (Loss) from Cash Flow Hedges, pre-adoption
Derivative [Line Items]
Change in value of derivative, pre-adoption				(29,234,000)
Reclassification of (gains) losses on derivatives to earnings, net, pre-adoption				(626,000)
Commodity Derivatives Propane [Member] \| Ferrellgas, L.P. [Member] \| Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member]
Derivative [Line Items]
Change in value of derivative			(24,839,000)
Reclassification of (gains) losses on derivatives to earnings, net			$ 16,245,000
Commodity Derivatives Propane [Member] \| Ferrellgas, L.P. [Member] \| Accumulated Net Gain (Loss) from Cash Flow Hedges, pre-adoption
Derivative [Line Items]
Change in value of derivative, pre-adoption				(29,234,000)
Reclassification of (gains) losses on derivatives to earnings, net, pre-adoption				$ (626,000)