Supplemental Financial Statement Information Supplemental Financial Statement Information (Assets Held for Sale) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Long Lived Assets Held-for-sale [Line Items]
Long Lived Assets Held-for-sale, Description	12	12
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Impairment of Long-Lived Assets to be Disposed of	$ 0	$ 12,112	$ 0
Gain (Loss) on Sale of Assets and Asset Impairment Charges	14,457	30,835	7,099
Assets held for disposal [Member]
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment	0	1,698	0
Assets held in use [Member]
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment	$ 14,457	$ 17,025	7,099
Ferrellgas, L.P. [Member]
Long Lived Assets Held-for-sale [Line Items]
Long Lived Assets Held-for-sale, Description	12	12
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Impairment of Long-Lived Assets to be Disposed of	$ 0	$ 12,112	0
Gain (Loss) on Sale of Assets and Asset Impairment Charges	14,457	30,835	7,099
Ferrellgas, L.P. [Member] | Assets held for disposal [Member]
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment	0	1,698	0
Ferrellgas, L.P. [Member] | Assets held in use [Member]
Reason for Changing Plan to Sell Assets Held-for-sale [Abstract]
Gain (Loss) on Disposition of Property Plant Equipment	$ 14,457	$ 17,025	$ 7,099