Debt Debt (Consolidated Interest Coverage Ratio) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jul. 31, 2017	Oct. 31, 2016	Jul. 31, 2017	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017
current consolidated interest coverage ratio	199.00%		199.00%
Debt Instrument, Covenant Compliance			67.5
Debt Instrument, Covenant Description			8.7
Ferrellgas, L.P. [Member]
current consolidated interest coverage ratio	199.00%		199.00%
Distributed Earnings	$ 0.40	$ 2.05
Debt Instrument, Covenant Compliance			67.5
Debt Instrument, Covenant Description			8.7
Maximum [Member]
required consolidated interest coverage ratio	175.00%		175.00%	250.00%	175.00%	175.00%	175.00%
Maximum [Member] | Ferrellgas, L.P. [Member]
required consolidated interest coverage ratio	175.00%		175.00%	250.00%	175.00%	175.00%	175.00%
Minimum [Member]
required consolidated interest coverage ratio	250.00%		250.00%	250.00%	250.00%	250.00%	250.00%
Minimum [Member] | Ferrellgas, L.P. [Member]
required consolidated interest coverage ratio	250.00%		250.00%	250.00%	250.00%	250.00%	250.00%
Interest Coverage Covenant [Member]
Debt Instrument, Covenant Compliance			15.9
Debt Instrument, Covenant Description			27.8
Interest Coverage Covenant [Member] | Ferrellgas, L.P. [Member]
Debt Instrument, Covenant Compliance	15.9
Debt Instrument, Covenant Description	27.8