Commitments and Contingencies (Details) lb in Millions, gal in Millions, bu in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2019 USD ($) MMBTU T lb bu gal	Jul. 31, 2018 USD ($)	Jul. 31, 2019 USD ($) MMBTU T lb bu gal	Jul. 31, 2018 USD ($)
One Earth Energy And Nu Gen Energy [Member]
Commitments and Contingencies (Details) [Line Items]
Quantity of Bushels under Forward Purchase Contract (in US Bushels) | bu	5.6		5.6
Quantity Of Natural Gas Under Sales Commitment (in Millions of British Thermal Units) | MMBTU	1,182,000		1,182,000
Quantity of Ethanol under Sales Commitment (in US Gallons) | gal	35.2		35.2
Quantity of Distillers Grains Under Sales Commitment (in US Tons) | T	30,100		30,100
Quantity of Non-food Grade Corn Oil Under Sales Commitments (in Pounds) | lb	14.9		14.9
Refined Coal [Member]
Commitments and Contingencies (Details) [Line Items]
Fees Incurred By Subsidiary | $	$ 1.2	$ 3.4	$ 2.8	$ 5.1