Consolidated Statements Of Partners' Deficit - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Apr. 30, 2020	Apr. 30, 2019	Jul. 31, 2019
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	$ (1,144,675)	$ (1,191,384)	$ (1,138,938)	$ (1,083,350)	$ (1,111,739)	$ (1,034,477)	$ (1,138,938)	$ (1,034,477)
Contributions in connection with non-cash ESOP compensation charges	757	630	795	(4)	1,944	2,748
Cumulative adjustment for lease accounting standard									$ (1,375)
Distributions		(157)	(1)		(157)	(9,915)
Net earnings	(15,471)	48,791	(45,717)	20,760	43,875	(57,508)	(12,397)	7,127
Other comprehensive income (loss)	2,572	(2,555)	(6,148)	8,286	(17,273)	(12,587)	(6,131)	(21,574)
Partners' capital balance, ending	(1,156,817)	(1,144,675)	(1,191,384)	(1,054,308)	(1,083,350)	(1,111,739)	(1,156,817)	(1,054,308)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(23,126)	(20,598)	(14,512)	(9,049)	8,050	20,510	(14,512)	20,510
Other comprehensive income (loss)	2,546	(2,528)	(6,086)	8,203	(17,099)	(12,460)
Partners' capital balance, ending	(20,580)	(23,126)	(20,598)	(846)	(9,049)	8,050	(20,580)	(846)
Parent [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(1,136,934)	(1,183,237)	(1,131,233)	(1,076,184)	(1,104,354)	(1,027,785)	(1,131,233)	(1,027,785)
Contributions in connection with non-cash ESOP compensation charges	749	624	787	(4)	1,925	2,720
Cumulative adjustment for lease accounting standard									(1,361)
Distributions						(9,814)		(9,814)
Net earnings	(15,393)	48,207	(45,344)	20,461	43,344	(57,015)
Other comprehensive income (loss)	2,546	(2,528)	(6,086)	8,203	(17,099)	(12,460)
Partners' capital balance, ending	(1,149,032)	(1,136,934)	(1,183,237)	(1,047,524)	(1,076,184)	(1,104,354)	(1,149,032)	(1,047,524)
Non-Controlling Interest [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(7,741)	(8,147)	(7,705)	(7,166)	(7,385)	(6,692)	(7,705)	(6,692)
Contributions in connection with non-cash ESOP compensation charges	8	6	8		19	28
Cumulative adjustment for lease accounting standard									(14)
Distributions		(157)	(1)		(157)	(101)
Net earnings	(78)	584	(373)	299	531	(493)
Other comprehensive income (loss)	26	(27)	(62)	83	(174)	(127)
Partners' capital balance, ending	$ (7,785)	$ (7,741)	$ (8,147)	$ (6,784)	$ (7,166)	$ (7,385)	$ (7,785)	$ (6,784)
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	97,152,700	97,152,700
Partners' capital balance, beginning	$ (1,043,361)	$ (1,091,704)	$ (1,046,245)	$ (997,154)	$ (1,041,971)	$ (978,503)	$ (1,046,245)	$ (978,503)
Contributions in connection with non-cash ESOP compensation charges	741	618	779	(4)	1,906	2,693
Cumulative adjustment for lease accounting standard									(1,347)
Distributions						(9,716)
Net earnings	$ (15,239)	$ 47,725	$ (44,891)	$ 20,256	$ 42,911	$ (56,445)
Partners' capital balance (in shares)	97,152,700	97,152,700	97,152,700	97,152,700	97,152,700	97,152,700	97,152,700	97,152,700
Partners' capital balance, ending	$ (1,057,859)	$ (1,043,361)	$ (1,091,704)	$ (976,902)	$ (997,154)	$ (1,041,971)	$ (1,057,859)	$ (976,902)
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	989,900	989,900
Partners' capital balance, beginning	$ (70,447)	$ (70,935)	$ (70,476)	$ (69,981)	$ (70,433)	$ (69,792)	$ (70,476)	$ (69,792)
Contributions in connection with non-cash ESOP compensation charges	8	6	8		19	27
Cumulative adjustment for lease accounting standard									(14)
Distributions						(98)
Net earnings	$ (154)	$ 482	$ (453)	$ 205	$ 433	$ (570)
Partners' capital balance (in shares)	989,900	989,900	989,900	989,900	989,900	989,900	989,900	989,900
Partners' capital balance, ending	$ (70,593)	$ (70,447)	$ (70,935)	$ (69,776)	$ (69,981)	$ (70,433)	$ (70,593)	$ (69,776)
Ferrellgas, L.P. [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(783,852)	(824,130)	(780,403)	(727,011)	(748,746)	(680,078)	(780,403)	(680,078)
Contributions in connection with non-cash ESOP compensation charges	757	630	795	(4)	1,944	2,748
Cumulative adjustment for lease accounting standard									(1,375)
Distributions		(15,553)	(101)		(15,553)	(10,015)	(15,654)	(25,568)
Net earnings	(7,720)	57,756	(36,898)	29,554	52,617	(48,814)	13,138	33,357
Other comprehensive income (loss)	2,572	(2,555)	(6,148)	8,286	(17,273)	(12,587)	(6,131)	(21,574)
Partners' capital balance, ending	(788,243)	(783,852)	(824,130)	(689,175)	(727,011)	(748,746)	(788,243)	(689,175)
Ferrellgas, L.P. [Member] | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(23,350)	(20,795)	(14,647)	(9,127)	8,146	20,733	(14,647)	20,733
Other comprehensive income (loss)	2,572	(2,555)	(6,148)	8,286	(17,273)	(12,587)
Partners' capital balance, ending	(20,778)	(23,350)	(20,795)	(841)	(9,127)	8,146	(20,778)	(841)
Ferrellgas, L.P. [Member] | Common Unitholders [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(752,985)	(795,385)	(758,186)	(710,796)	(749,411)	(693,896)	(758,186)	(693,896)
Contributions in connection with non-cash ESOP compensation charges	749	624	787	(4)	1,925	2,720
Cumulative adjustment for lease accounting standard									(1,361)
Distributions		(15,396)	(100)		(15,396)	(9,914)
Net earnings	(7,642)	57,172	(36,525)	29,255	52,086	(48,321)
Partners' capital balance, ending	(759,878)	(752,985)	(795,385)	(681,545)	(710,796)	(749,411)	(759,878)	(681,545)
Ferrellgas, L.P. [Member] | General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Partners' capital balance, beginning	(7,517)	(7,950)	(7,570)	(7,088)	(7,481)	(6,915)	(7,570)	(6,915)
Contributions in connection with non-cash ESOP compensation charges	8	6	8		19	28
Cumulative adjustment for lease accounting standard									$ (14)
Distributions		(157)	(1)		(157)	(101)
Net earnings	(78)	584	(373)	299	531	(493)
Partners' capital balance, ending	$ (7,587)	$ (7,517)	$ (7,950)	$ (6,789)	$ (7,088)	$ (7,481)	$ (7,587)	$ (6,789)