Consolidated Statements Of Partners' Deficit - USD ($)	3 Months Ended				6 Months Ended
	Jan. 31, 2021	Oct. 31, 2020	Jan. 31, 2020	Oct. 31, 2019	Jan. 31, 2021	Jan. 31, 2020
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	$ (1,246,096,000)	$ (1,208,268,000)	$ (1,191,384,000)	$ (1,138,938,000)	$ (1,208,268,000)	$ (1,138,938,000)
Contributions in connection with non-cash ESOP compensation charges	762,000	708,000	630,000	795,000
Distributions			(157,000)	(1,000)
Net income (loss)	63,991,000	(46,453,000)	48,791,000	(45,717,000)	17,538,000	3,074,000
Other comprehensive income (loss)	28,516,000	7,917,000	(2,555,000)	(6,148,000)	36,433,000	(8,703,000)
Partners' capital balance, ending	(1,152,827,000)	(1,246,096,000)	(1,144,675,000)	(1,191,384,000)	(1,152,827,000)	(1,144,675,000)
Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				(1,375,000)		(1,375,000)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	5,534,000	(2,303,000)	(20,598,000)	(14,512,000)	(2,303,000)	(14,512,000)
Other comprehensive income (loss)	28,228,000	7,837,000	(2,528,000)	(6,086,000)
Partners' capital balance, ending	33,762,000	5,534,000	(23,126,000)	(20,598,000)	33,762,000	(23,126,000)
Parent [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(1,237,566,000)	(1,200,042,000)	(1,183,237,000)	(1,131,233,000)	(1,200,042,000)	(1,131,233,000)
Contributions in connection with non-cash ESOP compensation charges	754,000	701,000	624,000	787,000
Net income (loss)	63,267,000	(46,062,000)	48,207,000	(45,344,000)
Other comprehensive income (loss)	28,228,000	7,837,000	(2,528,000)	(6,086,000)
Partners' capital balance, ending	(1,145,317,000)	(1,237,566,000)	(1,136,934,000)	(1,183,237,000)	(1,145,317,000)	(1,136,934,000)
Parent [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				(1,361,000)		(1,361,000)
Non-Controlling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(8,530,000)	(8,226,000)	(8,147,000)	(7,705,000)	(8,226,000)	(7,705,000)
Contributions in connection with non-cash ESOP compensation charges	8,000	7,000	6,000	8,000
Distributions			(157,000)	(1,000)
Net income (loss)	724,000	(391,000)	584,000	(373,000)
Other comprehensive income (loss)	288,000	80,000	(27,000)	(62,000)
Partners' capital balance, ending	$ (7,510,000)	$ (8,530,000)	$ (7,741,000)	(8,147,000)	$ (7,510,000)	(7,741,000)
Non-Controlling Interest [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				$ (14,000)		$ (14,000)
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	$ (1,171,359,000)	$ (1,126,452,000)	$ (1,091,704,000)	$ (1,046,245,000)	$ (1,126,452,000)	$ (1,046,245,000)
Contributions in connection with non-cash ESOP compensation charges	746,000	694,000	618,000	779,000
Distributions	0
Net income (loss)	$ 62,634,000	$ (45,601,000)	$ 47,725,000	$ (44,891,000)
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	$ (1,107,979,000)	$ (1,171,359,000)	$ (1,043,361,000)	$ (1,091,704,000)	$ (1,107,979,000)	$ (1,043,361,000)
Common Unitholders [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				$ (1,347,000)		$ (1,347,000)
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	$ (71,741,000)	$ (71,287,000)	$ (70,935,000)	$ (70,476,000)	$ (71,287,000)	$ (70,476,000)
Contributions in connection with non-cash ESOP compensation charges	8,000	7,000	6,000	8,000
Net income (loss)	$ 633,000	$ (461,000)	$ 482,000	$ (453,000)
Partners' capital balance (in shares)	989,900	989,900	989,900	989,900	989,900	989,900
Partners' capital balance, ending	$ (71,100,000)	$ (71,741,000)	$ (70,447,000)	$ (70,935,000)	$ (71,100,000)	$ (70,447,000)
General Partner [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				(14,000)		(14,000)
Ferrellgas, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(862,117,000)	(831,991,000)	(824,130,000)	(780,403,000)	(831,991,000)	(780,403,000)
Contributions in connection with non-cash ESOP compensation charges	762,000	708,000	630,000	795,000
Distributions			(15,553,000)	(101,000)
Net income (loss)	71,750,000	(38,751,000)	57,756,000	(36,898,000)	32,999,000	20,858,000
Other comprehensive income (loss)	28,516,000	7,917,000	(2,555,000)	(6,148,000)	36,433,000	(8,703,000)
Partners' capital balance, ending	(761,089,000)	(862,117,000)	(783,852,000)	(824,130,000)	(761,089,000)	(783,852,000)
Ferrellgas, L.P. [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				(1,375,000)		(1,375,000)
Ferrellgas, L.P. [Member] | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	5,604,000	(2,313,000)	(20,795,000)	(14,647,000)	(2,313,000)	(14,647,000)
Other comprehensive income (loss)	28,516,000	7,917,000	(2,555,000)	(6,148,000)
Partners' capital balance, ending	34,120,000	5,604,000	(23,350,000)	(20,795,000)	34,120,000	(23,350,000)
Ferrellgas, L.P. [Member] | Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(859,121,000)	(821,462,000)	(795,385,000)	(758,186,000)	(821,462,000)	(758,186,000)
Contributions in connection with non-cash ESOP compensation charges	754,000	701,000	624,000	787,000
Distributions			(15,396,000)	(100,000)
Net income (loss)	71,026,000	(38,360,000)	57,172,000	(36,525,000)
Partners' capital balance, ending	(787,341,000)	(859,121,000)	(752,985,000)	(795,385,000)	(787,341,000)	(752,985,000)
Ferrellgas, L.P. [Member] | Common Unitholders [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				(1,361,000)		(1,361,000)
Ferrellgas, L.P. [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(8,600,000)	(8,216,000)	(7,950,000)	(7,570,000)	(8,216,000)	(7,570,000)
Contributions in connection with non-cash ESOP compensation charges	8,000	7,000	6,000	8,000
Distributions			(157,000)	(1,000)
Net income (loss)	724,000	(391,000)	584,000	(373,000)
Partners' capital balance, ending	$ (7,868,000)	$ (8,600,000)	$ (7,517,000)	(7,950,000)	$ (7,868,000)	(7,517,000)
Ferrellgas, L.P. [Member] | General Partner [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning				$ (14,000)		$ (14,000)