Segment Reporting - Assets (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jul. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 1,388,120	$ 1,363,281
Propane and related equipment sales
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,315,233	1,196,084
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	72,887	167,197
Ferrellgas, L.P. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,387,962	1,363,246
Ferrellgas, L.P. [Member] | Propane and related equipment sales
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	1,315,233	1,196,084
Ferrellgas, L.P. [Member] | Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 72,729	$ 167,162