Consolidated Statements Of Partners' Deficit - USD ($)	3 Months Ended						12 Months Ended
	Jul. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2017	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		$ (1,138,938,000)		$ (1,034,477,000)		$ (757,510,000)	$ (1,138,938,000)	$ (1,034,477,000)	$ (757,510,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							2,871,000	5,693,000	13,859,000
Distributions							(158,000)	(10,229,000)	(39,970,000)
Net loss	$ (70,605,000)	(45,717,000)			$ (217,797,000)	(48,316,000)	(83,002,000)	(64,545,000)	(256,825,000)
Other comprehensive income (loss)							12,334,000	(35,380,000)	5,969,000
Partners' capital balance, ending	(1,208,268,000)		$ (1,138,938,000)		(1,034,477,000)		(1,208,268,000)	(1,138,938,000)	(1,034,477,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(70,605,000)	(45,717,000)			(217,797,000)	(48,316,000)	(83,002,000)	(64,545,000)	(256,825,000)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(14,512,000)		20,510,000		14,601,000	(14,512,000)	20,510,000	14,601,000
Other comprehensive income (loss)							12,209,000	(35,022,000)	5,909,000
Partners' capital balance, ending	(2,303,000)		(14,512,000)		20,510,000		(2,303,000)	(14,512,000)	20,510,000
Parent [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,131,233,000)		(1,027,785,000)		(753,578,000)	(1,131,233,000)	(1,027,785,000)	(753,578,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							2,842,000	5,635,000	13,719,000
Distributions							0	(9,814,000)	(39,254,000)
Net loss							(82,499,000)	(64,247,000)	(254,581,000)
Other comprehensive income (loss)							12,209,000	(35,022,000)	5,909,000
Partners' capital balance, ending	(1,200,042,000)		(1,131,233,000)		(1,027,785,000)		(1,200,042,000)	(1,131,233,000)	(1,027,785,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							(82,499,000)	(64,247,000)	(254,581,000)
Non-Controlling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		$ (7,705,000)		$ (6,692,000)		$ (3,932,000)	(7,705,000)	(6,692,000)	(3,932,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							29,000	58,000	140,000
Distributions							(158,000)	(415,000)	(716,000)
Net loss							(503,000)	(298,000)	(2,244,000)
Other comprehensive income (loss)							125,000	(358,000)	60,000
Partners' capital balance, ending	$ (8,226,000)		$ (7,705,000)		$ (6,692,000)		(8,226,000)	(7,705,000)	(6,692,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							$ (503,000)	$ (298,000)	$ (2,244,000)
Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance (in shares)		97,152,700		97,152,700		97,152,700	97,152,700	97,152,700	97,152,700
Partners' capital balance, beginning		$ (1,046,245,000)		$ (978,503,000)		$ (701,188,000)	$ (1,046,245,000)	$ (978,503,000)	$ (701,188,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							2,814,000	5,579,000	13,582,000
Distributions								(9,716,000)	(38,862,000)
Net loss							$ (81,674,000)	$ (63,605,000)	$ (252,035,000)
Partners' capital balance (in shares)	97,152,700		97,152,700		97,152,700		97,152,700	97,152,700	97,152,700
Partners' capital balance, ending	$ (1,126,452,000)		$ (1,046,245,000)		$ (978,503,000)		$ (1,126,452,000)	$ (1,046,245,000)	$ (978,503,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							$ (81,674,000)	$ (63,605,000)	$ (252,035,000)
General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance (in shares)		989,900		989,900		989,900	989,900	989,900	989,900
Partners' capital balance, beginning		$ (70,476,000)		$ (69,792,000)		$ (66,991,000)	$ (70,476,000)	$ (69,792,000)	$ (66,991,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							28,000	56,000	137,000
Distributions								(98,000)	(392,000)
Net loss							$ (825,000)	$ (642,000)	$ (2,546,000)
Partners' capital balance (in shares)	989,900		989,900		989,900		989,900	989,900	989,900
Partners' capital balance, ending	$ (71,287,000)		$ (70,476,000)		$ (69,792,000)		$ (71,287,000)	$ (70,476,000)	$ (69,792,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							(825,000)	(642,000)	(2,546,000)
Ferrellgas Partners Finance Corp. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							(5,827)	(3,999)	(2,115)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		$ 2,858		$ 2,850		$ 1,000	2,858	2,850	1,000
Capital contribution							5,819	4,007	3,965
Net loss							(5,827)	(3,999)	(2,115)
Stockholders' equity balance	$ 2,850		$ 2,858		$ 2,850		$ 2,850	$ 2,858	$ 2,850
Ferrellgas Partners Finance Corp. [Member] | Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance (in shares)		1,000		1,000		1,000	1,000	1,000	1,000
Stockholders' equity balance		$ 1,000		$ 1,000		$ 1,000	$ 1,000	$ 1,000	$ 1,000
Stockholders' equity balance (in shares)	1,000		1,000		1,000		1,000	1,000	1,000
Stockholders' equity balance	$ 1,000		$ 1,000		$ 1,000		$ 1,000	$ 1,000	$ 1,000
Ferrellgas Partners Finance Corp. [Member] | Additional Paid-in Capital [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		33,027		29,020		25,055	33,027	29,020	25,055
Capital contribution							5,819	4,007	3,965
Net loss							0	0	0
Stockholders' equity balance	38,846		33,027		29,020		38,846	33,027	29,020
Ferrellgas Partners Finance Corp. [Member] | Accumulated deficit [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							(5,827)	(3,999)	(2,115)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		(31,169)		(27,170)		(25,055)	(31,169)	(27,170)	(25,055)
Capital contribution							0	0	0
Net loss							(5,827)	(3,999)	(2,115)
Stockholders' equity balance	(36,996)		(31,169)		(27,170)		(36,996)	(31,169)	(27,170)
Ferrellgas, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(780,403,000)		(680,078,000)		(406,798,000)	(780,403,000)	(680,078,000)	(406,798,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							2,871,000	5,693,000	13,859,000
Distributions							(15,654,000)	(41,121,000)	(70,962,000)
Net loss	(62,902,000)	(36,898,000)	(62,874,000)	(48,814,000)	(209,134,000)	(39,699,000)	(49,764,000)	(29,517,000)	(222,146,000)
Other comprehensive income (loss)							12,334,000	(35,380,000)	5,969,000
Partners' capital balance, ending	(831,991,000)		(780,403,000)		(680,078,000)		(831,991,000)	(780,403,000)	(680,078,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(62,902,000)	(36,898,000)	(62,874,000)	(48,814,000)	(209,134,000)	(39,699,000)	(49,764,000)	(29,517,000)	(222,146,000)
Ferrellgas, L.P. [Member] | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(14,647,000)		20,733,000		14,764,000	(14,647,000)	20,733,000	14,764,000
Other comprehensive income (loss)							12,334,000	(35,380,000)	5,969,000
Partners' capital balance, ending	(2,313,000)		(14,647,000)		20,733,000		(2,313,000)	(14,647,000)	20,733,000
Ferrellgas, L.P. [Member] | Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(758,186,000)		(693,896,000)		(417,467,000)	(758,186,000)	(693,896,000)	(417,467,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							2,842,000	5,635,000	13,719,000
Distributions							(15,496,000)	(40,706,000)	(70,246,000)
Net loss							(49,261,000)	(29,219,000)	(219,902,000)
Partners' capital balance, ending	(821,462,000)		(758,186,000)		(693,896,000)		(821,462,000)	(758,186,000)	(693,896,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							(49,261,000)	(29,219,000)	(219,902,000)
Ferrellgas, L.P. [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(7,570,000)		(6,915,000)		(4,095,000)	(7,570,000)	(6,915,000)	(4,095,000)
Contributions in connection with non-cash ESOP and stock and unit-based compensation charges							29,000	58,000	140,000
Distributions							(158,000)	(415,000)	(716,000)
Net loss							(503,000)	(298,000)	(2,244,000)
Partners' capital balance, ending	(8,216,000)		(7,570,000)		(6,915,000)		(8,216,000)	(7,570,000)	(6,915,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss							(503,000)	(298,000)	(2,244,000)
Ferrellgas Finance Corp. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							(6,010)	(5,625)	(5,216)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		$ 2,941		$ 2,600		$ 2,600	2,941	2,600	2,600
Capital contribution							5,669	5,966	5,216
Net loss							(6,010)	(5,625)	(5,216)
Stockholders' equity balance	$ 2,600		$ 2,941		$ 2,600		$ 2,600	$ 2,941	$ 2,600
Ferrellgas Finance Corp. [Member] | Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance (in shares)		1,000		1,000		1,000	1,000	1,000	1,000
Stockholders' equity balance		$ 1,000		$ 1,000		$ 1,000	$ 1,000	$ 1,000	$ 1,000
Stockholders' equity balance (in shares)	1,000		1,000		1,000		1,000	1,000	1,000
Stockholders' equity balance	$ 1,000		$ 1,000		$ 1,000		$ 1,000	$ 1,000	$ 1,000
Ferrellgas Finance Corp. [Member] | Additional Paid-in Capital [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		78,518		72,552		67,336	78,518	72,552	67,336
Capital contribution							5,669	5,966	5,216
Net loss							0	0	0
Stockholders' equity balance	84,187		78,518		72,552		84,187	78,518	72,552
Ferrellgas Finance Corp. [Member] | Accumulated deficit [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Net loss							(6,010)	(5,625)	(5,216)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' equity balance		(76,577)		$ (70,952)		$ (65,736)	(76,577)	(70,952)	(65,736)
Capital contribution							0	0	0
Net loss							(6,010)	(5,625)	(5,216)
Stockholders' equity balance	$ (82,587)		(76,577)		$ (70,952)		(82,587)	(76,577)	$ (70,952)
Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,375,000)					(1,375,000)
Partners' capital balance, ending			(1,375,000)					(1,375,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Parent [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,361,000)					(1,361,000)
Partners' capital balance, ending			(1,361,000)					(1,361,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Non-Controlling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(14,000)					(14,000)
Partners' capital balance, ending			(14,000)					(14,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,347,000)					(1,347,000)
Partners' capital balance, ending			(1,347,000)					(1,347,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(14,000)					(14,000)
Partners' capital balance, ending			(14,000)					(14,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Ferrellgas, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,375,000)					(1,375,000)
Partners' capital balance, ending			(1,375,000)					(1,375,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Ferrellgas, L.P. [Member] | Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		(1,361,000)					(1,361,000)
Partners' capital balance, ending			(1,361,000)					(1,361,000)
Cumulative Effect, Period of Adoption, Adjustment [Member] | Ferrellgas, L.P. [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning		$ (14,000)					$ (14,000)
Partners' capital balance, ending			$ (14,000)					$ (14,000)