Debt - Covenants (Details)	6 Months Ended
Jan. 31, 2019 USD ($) item
Debt Instrument [Line Items]
Number of quarters for required fixed charge coverage ratio	4
Maximum restricted payments \| $	$ 50,000,000
Number of quarters for restricted payments	16
Current fixed charge coverage ratio	1.38
Dividends allowed \| $	$ 0
Minimum [Member]
Debt Instrument [Line Items]
Required fixed charge coverage ratio	1.75
Ferrellgas, L.P. [Member]
Debt Instrument [Line Items]
Number of quarters for required fixed charge coverage ratio	4
Current fixed charge coverage ratio	1.67
Ferrellgas, L.P. [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Required fixed charge coverage ratio	1.75

The amount of dividends that may be paid, under the debt securities covenant, while the entity is in default.

No definition available.

Name:	fgp_DebtSecuritiesCovenantDividendsPayableWhileInDefault
Namespace Prefix:	fgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The current ratio of trailing four quarters EBITDA to interest expense, under the indenture governing the debt securities. Compliance status entitles, or prevents, the entity from taking certain actions.

+ References

No definition available.

+ Details

Name:	fgp_DebtSecuritiesCurrentFixedChargeCoverageRatio
Namespace Prefix:	fgp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum amount of restricted payments the entity may make under certain conditions, per the indenture governing debt securities.

+ References

No definition available.

+ Details

Name:	fgp_DebtSecuritiesMaximumRestrictedPaymentInEventOfDefault
Namespace Prefix:	fgp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of quarters during which the restricted payment may be made.

+ References

No definition available.

+ Details

Name:	fgp_DebtSecuritiesNumberOfQuartersDuringWhichRestrictedPaymentMayBeMade
Namespace Prefix:	fgp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The required ratio of trailing four quarters EBITDA to interest expense, under the indenture governing the debt securities. Compliance status entitles, or prevents, the entity from taking certain actions.

+ References

No definition available.

+ Details

Name:	fgp_DebtSecuritiesRequiredFixedChargeCoverageRatio
Namespace Prefix:	fgp_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of quarters EBITDA used in the required fixed charge coverage ratio.

+ References

No definition available.

+ Details

Name:	fgp_DebtSecuritiesRequiredFixedChargeCoverageRatioMeasurementPeriodNumberOfQuarters
Namespace Prefix:	fgp_
Data Type:	xbrli:integerItemType
Balance Type:	na
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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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