Partners' Capital (Narrative) (Details) - USD ($)					3 Months Ended					12 Months Ended
	Sep. 14, 2017	Aug. 22, 2017	Sep. 14, 2015	Aug. 20, 2015	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jan. 31, 2016	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Capital Unit [Line Items]
Limited partner ownership interest										5.00%	5.00%
Common unitholders, units outstanding					97,152,665					97,152,665	98,002,665
General partner ownership interest										1.00%
Minimum percentage ownership of outstanding common units resulting in non voting of owners										20.00%
Cash distributions declared per common unit					$ 0.10					$ 0.40	$ 2.05
Stock Issued During Period, Shares, Treasury Stock Reissued												1,500,000
Stock Issued During Period, Value, Other												$ 42,000,000
Offering of common units, shares												6,300,000
Proceeds from offering of common units												$ 139,100,000
Stock issued during the period for acquisition, shares												11,300,000
Stock issued during the period for acquisition, value												$ 260,000,000
Partners' Capital Account, Units, Treasury Units Purchased								900,000	2,400,000
Energy Related Inventory, Crude Oil and Natural Gas Liquids								$ 23,000
Payments for Repurchase of Common Stock										$ (15,851,000)	$ (46,432,000)	0
Cash received from contributions										0	$ 32,000	$ 4,456,000
Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Paid										418,900,000
General Partners' Cumulative Cash Distributions					$ 4,300,000					$ 4,300,000
General partner ownership interest										1.00%
Distribution Made to Limited Partner, Cash Distributions Declared								$ 15,900,000	$ 46,400,000
Cash contributions from limited partner							$ 166,100,000
Partners' Capital Account, Units, Treasury Units Purchased								900,000	2,400,000
Energy Related Inventory, Crude Oil and Natural Gas Liquids								$ 23,000
Asset contribution										$ 822,500,000
General Partners' Contributed Capital					$ 8,400,000					$ 8,400,000
General Partner [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared									$ 500,000
Cash contributions from limited partner						$ 1,700,000
Ferrell Companies [Member]
Capital Unit [Line Items]
Limited partner ownership interest										23.00%
FCI Trading Corp. [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding					195,686					195,686	195,686
Ferrell Propane, Inc. [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding					51,204					51,204	51,204
Ferrell Companies Beneficial Ownership [Member]
Capital Unit [Line Items]
Limited partner ownership interest										23.40%
JEF Capital Management [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding					4,758,859					4,758,859
Ferrell Resources Holdings, Inc. [Member]
Capital Unit [Line Items]
Common unitholders, units outstanding					4,616					4,616
Jamex Marketing, LLC [Member]
Capital Unit [Line Items]
Partners' Capital Account, Units, Treasury Units Purchased										900,000
Payments for Repurchase of Common Stock									45,900,000	$ 16,900,000
Jamex Marketing, LLC [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Payments for Repurchase of Common Stock								16,900,000	45,900,000
Ferrellgas Partners [Member]
Capital Unit [Line Items]
Limited partner ownership interest										98.00%
Ferrellgas Partners [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Cash contributions from limited partner											$ 42,200,000
Non-cash contributions											3,000,000
General Partner [Member]
Capital Unit [Line Items]
General partner ownership interest										2.00%
Cash received from contributions										$ 1,700,000
Non-cash contributions										$ 400,000	700,000
General Partner [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
General partner ownership interest										1.0101%
Cash received from contributions										$ 1,700,000
Non-cash contributions										$ 200,000	400,000
Subsequent Event [Member]
Capital Unit [Line Items]
Cash distribution declared date		Aug. 22, 2017
Cash distributions declared per common unit					$ 0.10
Cash distributions, payment date	Sep. 14, 2017
Subsequent Event [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Cash distribution declared date				Aug. 22, 2017
Cash distributions, payment date			Sep. 14, 2017
Subsequent Event [Member] | Ferrell Companies [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared	$ 2,253,000
Subsequent Event [Member] | FCI Trading Corp. [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared	20,000
Subsequent Event [Member] | Ferrell Propane, Inc. [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared	5,000
Subsequent Event [Member] | Ferrellgas Partners [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared											9,800,000
Subsequent Event [Member] | General Partner [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared	$ 98,000
Subsequent Event [Member] | General Partner [Member] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Distribution Made to Limited Partner, Cash Distributions Declared											$ 100,000
Credit Facility [Domain]
Capital Unit [Line Items]
Payments for Repurchase of Common Stock								$ 16,900,000	$ 45,900,000
Credit Facility [Domain] | Ferrellgas, L.P. [Member]
Capital Unit [Line Items]
Limited partner ownership interest										5.00%