Supplemental Financial Statement Information Supplemental Financial Statement Information (Loss on asset sales and disposals) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Loss on asset sales and disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	$ 35,515	$ 0	$ 35,515	$ 0
Loss on sale of assets and other	3,734	45	4,629	6,468
Loss on asset sales and disposals	39,249	45	40,144	6,468
Ferrellgas, L.P. [Member]
Loss on asset sales and disposals [Line Items]
Impairment of Long-Lived Assets to be Disposed of	35,515	0	35,515	0
Loss on sale of assets and other	3,734	45	4,629	6,468
Loss on asset sales and disposals	$ 39,249	$ 45	$ 40,144	$ 6,468