Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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

- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

+ Details

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

- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Definition

Aggregate amount of net income allocated to limited partners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

+ Details

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

- Definition

The amount of net income or loss for the period per each limited partnership and general partnership unit in instances when basic and diluted earnings per unit are the same amount and aggregated on the face of the financial statements. Basic earnings per unit is the amount of net income or loss for the period per unit outstanding during the reporting period. Diluted earnings per unit includes the amount of net income or loss for the period available to each limited and general partnership unit outstanding during the reporting period and to each unit that would have been outstanding assuming the issuance of units for all dilutive potential units outstanding during the reporting period.

+ References

No definition available.

+ Details

Name:	us-gaap_NetIncomeLossPerOutstandingLimitedPartnershipAndGeneralPartnershipUnitBasicAndDiluted
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4K
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591552-111686

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4569616-111683

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84161450&loc=SL4573702-111684

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4J
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4591551-111686

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=84161450&loc=SL4573702-111684

+ Details

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

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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

- Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fgp_MidstreamOperationsWaterSolutionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fgp_PropaneandrelatedequipmentsalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=fgp_ConsolidatedMidstreamOperationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Quarterly Data (Unaudited) (Summarized Unaudited Quarterly Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Goodwill, Impairment Loss														$ (219,870)
Revenues	$ 433,376	$ 538,109	$ 579,250	$ 379,542	$ 409,511	$ 509,472	$ 649,238	$ 471,146	$ 382,511	$ 532,551	$ 665,973	$ 443,355	$ 1,930,277	2,039,367	$ 2,024,390
Net earnings (loss)	(56,249)	6,691	38,528	(43,471)	(668,142)	18,918	57,755	(80,566)	(59,333)	36,220	86,371	(33,169)	(54,501)	(672,035)	30,089
Net earnings (loss) attributable to Ferrellgas Partners, L.P.	(55,768)	6,536	38,098	(43,073)	(661,434)	18,685	57,127	(79,793)	(58,775)	35,812	85,458	(32,875)	(54,207)	(665,415)	29,620
Common unitholders' interest in net earnings (loss)	$ (55,210)	$ 6,470	$ 37,717	$ (42,642)	$ (654,820)	$ 18,498	$ 56,556	$ (78,995)	$ (58,187)	$ 35,454	$ 84,603	$ (32,546)	$ (53,665)	$ (658,761)	$ 29,324
Basic and diluted net earnings (loss) per common unitholders' interest	$ (0.57)	$ 0.07	$ 0.39	$ (0.44)	$ (6.68)	$ 0.19	$ 0.58	$ (0.79)	$ (0.64)	$ 0.43	$ 0.89	$ (0.40)	$ (0.55)	$ (6.68)	$ 0.35
Asset Impairment Charges					$ 628,800								$ 0	$ 658,118	$ 0
Ferrellgas, L.P. [Member]
Goodwill, Impairment Loss														(219,870)
Revenues	$ 433,376	$ 538,109	$ 579,250	$ 379,542	409,511	$ 509,472	$ 649,238	$ 471,146	$ 382,511	$ 532,551	$ 665,973	$ 443,355	1,930,277	2,039,367	2,024,390
Net earnings (loss)	(47,614)	15,395	42,600	(39,440)	(664,091)	23,049	62,187	(76,536)	(55,249)	40,404	90,409	(29,137)	(29,059)	(655,391)	46,427
Asset Impairment Charges					628,800								$ 0	658,118	$ 0
Midstream Operations - Water Solutions [Member]
Goodwill, Impairment Loss								(29,316)
Midstream Operations - Water Solutions [Member] \| Ferrellgas, L.P. [Member]
Goodwill, Impairment Loss								(29,316)						(29,316)
Propane and related equipment sales [Member]
Goodwill, Impairment Loss														0
Gross margin from propane and other gas liquids sales (a)	126,774	171,950	202,346	123,187	125,690	186,668	202,027	123,550	128,087	191,983	230,175	129,547
Propane and related equipment sales [Member] \| Ferrellgas, L.P. [Member]
Goodwill, Impairment Loss														$ 0
Gross margin from propane and other gas liquids sales (a)	126,774	171,950	202,346	123,187	125,690	186,668	202,027	123,550	128,087	191,983	230,175	129,547
Consolidated Midstream Operations [Member]
Gross margin from propane and other gas liquids sales (a)	6,190	7,909	9,763	13,402	40,476	33,572	39,890	40,066	16,301	3,416	4,934	5,948
Consolidated Midstream Operations [Member] \| Ferrellgas, L.P. [Member]
Gross margin from propane and other gas liquids sales (a)	$ 6,190	$ 7,909	$ 9,763	$ 13,402	$ 40,476	$ 33,572	$ 39,890	$ 40,066	$ 16,301	$ 3,416	$ 4,934	$ 5,948