Supplemental Financial Statement Information - Other Current Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2019	Jul. 31, 2018
Supplemental Financial Statement Information [Line Items]
Accrued interest	$ 21,963	$ 22,222
Customer deposits and advances	26,323	22,829
Other	98,967	96,974
Other current liabilities	147,253	142,025
Ferrellgas, L.P. [Member]
Supplemental Financial Statement Information [Line Items]
Accrued interest	18,029	18,288
Customer deposits and advances	26,323	22,829
Other	98,967	96,974
Other current liabilities	$ 143,319	$ 138,091