Segment Reporting - Assets (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Jul. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,329,992	$ 1,363,281
Propane and related equipment sales
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,257,214	1,196,084
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	72,778	167,197
Ferrellgas, L.P. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,329,861	1,363,246
Ferrellgas, L.P. [Member] | Propane and related equipment sales
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,257,214	1,196,084
Ferrellgas, L.P. [Member] | Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 72,647	$ 167,162