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Debt - Components Of Long-Term Debt (Details) - USD ($) $ in Thousands	Jan. 31, 2021	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2017	Jun. 30, 2015	Jul. 31, 2014	Nov. 30, 2010
Schedule of Capitalization, Long-term Debt [Line Items]
Total long-term debt	$ 2,539,482	$ 2,541,074
Unamortized debt issuance and other costs	(30,207)	(35,583)
Less: current portion of long-term debt	501,865	859,095
Less: debt subject to compromise	357,000
Long-term debt	1,650,410	1,646,396
Fixed rate, 6.5%, due 2021
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 500,000	$ 500,000
Interest rate, as a percent	6.50%	6.50%					6.50%
Fixed rate, 6.75%, due 2023
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 500,000	$ 500,000
Interest rate, as a percent	6.75%	6.75%			6.75%
Fixed rate, 6.75%, due 2022
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 475,605	$ 475,937
Interest rate, as a percent	6.75%	6.75%				6.75%
Unamortized premium	$ 605	$ 937
Fixed rate, 8.625%, due 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	357,000	$ 357,000
Less: debt subject to compromise	$ 357,000
Interest rate, as a percent	8.625%	8.625%		8.625%
Fixed rate 10.00% Due 2025
Schedule of Capitalization, Long-term Debt [Line Items]
Senior secured debt	$ 703,270	$ 703,573
Interest rate, as a percent	10.00%		10.00%
Unamortized premium	$ 3,270	3,573
Notes payable Due 2021 to 2029
Schedule of Capitalization, Long-term Debt [Line Items]
Notes payable	3,607	4,564
Unamortized discount	$ 374	$ 537
Debt, Weighted Average Interest Rate	7.70%	9.40%
Ferrellgas, L.P. [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Total long-term debt	$ 2,182,482	$ 2,184,074
Unamortized debt issuance and other costs	(30,207)	(35,583)
Less: current portion of long-term debt	501,865	502,095
Long-term debt	1,650,410	1,646,396
Ferrellgas, L.P. [Member] \| Fixed rate, 6.5%, due 2021
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 500,000	$ 500,000
Interest rate, as a percent	6.50%	6.50%					6.50%
Ferrellgas, L.P. [Member] \| Fixed rate, 6.75%, due 2023
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 500,000	$ 500,000
Interest rate, as a percent	6.75%	6.75%			6.75%
Ferrellgas, L.P. [Member] \| Fixed rate, 6.75%, due 2022
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	$ 475,605	$ 475,937
Interest rate, as a percent	6.75%	6.75%				6.75%
Unamortized premium	$ 605	$ 937
Ferrellgas, L.P. [Member] \| Fixed rate, 8.625%, due 2020
Schedule of Capitalization, Long-term Debt [Line Items]
Unsecured senior notes	357,000
Less: debt subject to compromise	357,000
Ferrellgas, L.P. [Member] \| Fixed rate 10.00% Due 2025
Schedule of Capitalization, Long-term Debt [Line Items]
Senior secured debt	$ 703,270	703,573
Interest rate, as a percent	10.00%		10.00%
Unamortized premium	$ 3,270	3,573
Ferrellgas, L.P. [Member] \| Notes payable Due 2021 to 2029
Schedule of Capitalization, Long-term Debt [Line Items]
Notes payable	3,607	4,564
Unamortized discount	$ 374	$ 537
Debt, Weighted Average Interest Rate	7.70%	9.40%