Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Interim Period, Costs Not Allocable [Line Items]
Goodwill, Impairment Loss													$ 0
Revenues	$ 281,649	$ 412,130	$ 510,833	$ 293,214	$ 279,081	$ 479,625	$ 573,377	$ 352,309	$ 347,521	$ 515,810	$ 755,156	$ 454,655	1,497,826	$ 1,684,392	$ 2,073,142
Net loss	(70,605)	(15,471)	48,791	(45,717)					(217,797)	11,062	(1,774)	(48,316)	(83,002)	(64,545)	(256,825)
Net earnings (loss)	(69,969)	(15,393)	48,207	(45,344)	(71,037)	20,461	43,344	(57,015)	(215,684)	10,861	(1,843)	(47,915)	(82,499)	(64,247)	(254,581)
Common unitholders' interest in net earnings (loss)	$ (69,269)	$ (15,239)	$ 47,725	$ (44,891)	$ (70,327)	$ 20,256	$ 42,911	$ (56,445)	$ (213,527)	$ 10,752	$ (1,824)	$ (47,436)	$ (81,674)	$ (63,605)	$ (252,035)
Basic and diluted net loss per common unit	$ (0.71)	$ (0.16)	$ 0.49	$ (0.46)	$ (0.72)	$ 0.21	$ 0.44	$ (0.58)	$ (2.20)	$ 0.11	$ (0.02)	$ (0.49)	$ (0.84)	$ (0.65)	$ (2.59)
Loss on extinguishment of debt		$ 37,400											$ 37,399
Asset impairments											$ 10,000		0	$ 0	$ 10,005
Propane and related equipment sales [Member]
Interim Period, Costs Not Allocable [Line Items]
Gross margin from propane and other gas liquids sales (a)	$ 140,497	215,480	$ 247,404	$ 139,357	$ 127,764	$ 209,167	$ 238,581	$ 130,830	$ 126,115	$ 190,883	229,321	$ 123,243
Consolidated Midstream Operations [Member]
Interim Period, Costs Not Allocable [Line Items]
Gross margin from propane and other gas liquids sales (a)									(4,161)	8,077	10,209	12,635
Net loss					(71,672)	20,760	43,875	(57,508)
Ferrellgas, L.P. [Member]
Interim Period, Costs Not Allocable [Line Items]
Goodwill, Impairment Loss													0
Revenues	281,649	412,130	510,833	293,214	279,081	479,625	573,377	352,309	347,521	515,810	755,156	454,655	1,497,826	1,684,392	2,073,142
Net loss	(62,902)	(7,720)	57,756	(36,898)	(62,874)	29,554	52,617	(48,814)	(209,134)	19,840	6,847	(39,699)	(49,764)	$ (29,517)	(222,146)
Loss on extinguishment of debt		37,400											$ 37,399
Asset impairments											10,000				$ 10,005
Ferrellgas, L.P. [Member] | Propane and related equipment sales [Member]
Interim Period, Costs Not Allocable [Line Items]
Gross margin from propane and other gas liquids sales (a)	$ 140,497	$ 215,480	$ 247,404	$ 139,357	$ 127,764	$ 209,167	$ 238,581	$ 130,830	126,115	190,883	229,321	123,243
Ferrellgas, L.P. [Member] | Consolidated Midstream Operations [Member]
Interim Period, Costs Not Allocable [Line Items]
Gross margin from propane and other gas liquids sales (a)									$ (4,161)	$ 8,077	$ 10,209	$ 12,635