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.

No definition available.

+ Details

Name:	srt_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=fgp_SeniorNotes6.75PercentDue2023Member
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:	srt_OwnershipAxis=fgp_FerrellgasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=fgp_FerrellgasFinanceCorpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Guarantor financial information (Details) - USD ($) $ in Millions	Jul. 31, 2020	Jul. 31, 2019	Jun. 30, 2015
Fixed Rate Six Point Seven Five Due Two Thousand Twenty Three [Member]
Condensed Financial Statements, Captions [Line Items]
Aggregate principal amount			$ 500.0
Interest rate, as a percent	6.75%	6.75%	6.75%
Ferrellgas, L.P. [Member] \| Ferrellgas [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage	100.00%
Ferrellgas, L.P. [Member] \| Ferrellgas Finance Corp. [Member]
Condensed Financial Statements, Captions [Line Items]
Ownership percentage	100.00%
Ferrellgas, L.P. [Member] \| Fixed Rate Six Point Seven Five Due Two Thousand Twenty Three [Member]
Condensed Financial Statements, Captions [Line Items]
Aggregate principal amount	$ 500.0		$ 500.0
Interest rate, as a percent	6.75%		6.75%