Segment Reporting Segment Reporting (Reconciliation of Assets from Segment to Consolidated) (Details) - USD ($) $ in Thousands	Jan. 31, 2018	Jul. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 1,687,059	$ 1,609,969
Propane and related equipment sales [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,361,856	1,194,905
Midstream Operations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	309,952	399,356
Corporate Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	15,251	15,708
Ferrellgas, L.P. [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,687,050	1,609,948
Ferrellgas, L.P. [Member] | Propane and related equipment sales [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,361,856	1,194,905
Ferrellgas, L.P. [Member] | Midstream Operations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	309,952	399,356
Ferrellgas, L.P. [Member] | Corporate Segment [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 15,242	$ 15,687