Supplemental Financial Statement Information (Other Current Liabilities) (Details) - USD ($) $ in Thousands	Apr. 30, 2018	Jul. 31, 2017
Accrued interest	$ 50,586	$ 18,671
Customer deposits and advances	18,956	25,541
Other	89,333	82,012
Other current liabilities	158,875	126,224
Ferrellgas, L.P. [Member]
Accrued interest	38,954	14,737
Customer deposits and advances	18,956	25,541
Other	89,333	81,738
Other current liabilities	$ 147,243	$ 122,016