Partnership Organization And Formation (Details)	6 Months Ended
	Jan. 31, 2021 USD ($) employee item subsidiary shares	Jan. 31, 2020	Jan. 08, 2021 USD ($)	Jul. 31, 2020 shares	Jan. 31, 2017 USD ($)	Nov. 30, 2010 USD ($)
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of subsidiaries | subsidiary	2
Number of states in which entity operates	50
Debt subject to compromise	$ 357,000,000
Number of employees | employee	0
Fixed rate, 8.625%, due 2020
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Debt subject to compromise	$ 357,000,000
Aggregate principal amount					$ 175,000,000
Interest rate, as a percent	8.625%			8.625%	8.625%
Fixed rate, 6.5%, due 2021
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Aggregate principal amount						$ 500,000,000
Interest rate, as a percent	6.50%			6.50%		6.50%
P I K Term Loan Due Two Thousand Twenty Two [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Aggregate principal amount			$ 19,900,000
Interest rate, as a percent			20.00%
Ferrellgas, L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of general partners | item	3
Ferrellgas Partners LP [Member] | Ferrellgas, L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Limited partner interest	99.00%
Ferrellgas Partners LP [Member] | Ferrellgas Partners Finance Corp. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership percentage	100.00%
Ferrell Companies [Member] | Ferrellgas Partners LP [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Common stock shares outstanding | shares	22,800,000
Ferrellgas Inc., General Partner [Member] | Ferrellgas [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
General partner ownership interest	2.00%	2.00%
Ferrellgas Inc., General Partner [Member] | Ferrellgas Partners LP [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
General partner ownership interest	1.00%
Ferrellgas Inc., General Partner [Member] | Ferrellgas, L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
General partner ownership interest	1.0101%	1.0101%
Ferrellgas, L.P. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number of states in which entity operates	50
Number of employees | employee	0
Ferrellgas, L.P. [Member] | Fixed rate, 8.625%, due 2020
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Debt subject to compromise	$ 357,000,000
Ferrellgas, L.P. [Member] | Fixed rate, 6.5%, due 2021
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Aggregate principal amount	$ 500,000,000					$ 500,000,000
Interest rate, as a percent	6.50%			6.50%		6.50%
Ferrellgas, L.P. [Member] | Ferrellgas Finance Corp. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Ownership percentage	100.00%
Ferrellgas Partners Finance Corp. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Common stock shares outstanding | shares	1,000			1,000
Corporation formation proceeds from partnership	$ 1,000
Corporation formation shares granted to partnership | shares	1,000
Number of employees | employee	0
Ferrellgas Finance Corp. [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Common stock shares outstanding | shares	1,000			1,000
Corporation formation proceeds from partnership	$ 1,000
Corporation formation shares granted to partnership | shares	1,000
Number of employees | employee	0
Ferrellgas Finance Corp. [Member] | Fixed rate, 8.625%, due 2020
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Debt subject to compromise	$ 357,000,000
Ferrellgas Finance Corp. [Member] | Fixed rate, 6.5%, due 2021
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Aggregate principal amount	$ 500,000,000