Supplemental Financial Statement Information - Inventories (Details) MBbls in Thousands, $ in Thousands, gal in Millions	12 Months Ended
Jul. 31, 2019 USD ($) gal	Jul. 31, 2018 USD ($)	Sep. 30, 2016 MBbls
Supplemental Financial Statement Information [Line Items]
Propane gas and related products	$ 66,001	$ 71,180
Appliances, parts and supplies	14,453	12,514
Inventories	$ 80,454	83,694
Supply procurement contract duration	36 months
Net procurement of fixed priced propane by Ferrellgas in gallons	2.3		23
Ferrellgas, L.P. [Member]
Supplemental Financial Statement Information [Line Items]
Propane gas and related products	$ 66,001	71,180
Appliances, parts and supplies	14,453	12,514
Inventories	$ 80,454	$ 83,694
Net procurement of fixed priced propane by Ferrellgas in gallons \| gal	2.3
Ferrellgas, L.P. [Member] \| Maximum [Member]
Supplemental Financial Statement Information [Line Items]
Supply procurement contract duration	36 months

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Quantity of oil and gas subject to delivery commitment.

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Carrying amount as of the balance sheet date of product derived from petroleum during the processing of oil or natural gas which is then used as a heat source or fuel.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount, after of valuation reserves and allowances, of inventory, classified as other, expected to be sold, or consumed within one year or operating cycle, if longer.

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