Derivative Financial Instruments (Details) bu in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016 USD ($) bu	Oct. 31, 2015 USD ($)	Oct. 31, 2016 USD ($) bu	Oct. 31, 2015 USD ($)	Jan. 31, 2016 bu
Disclosure Text Block Supplement [Abstract]
Derivative, Nonmonetary Notional Amount, Volume (in US Bushels) | bu			0.3
Quantity of Bushels under Forward Purchase Contract (in US Bushels) | bu	4.5		4.5		0.7
Debt Instrument, Collateral Amount | $	$ 46,000		$ 46,000
Gain on Derivative Instruments, Pretax | $	$ 115,000	$ 108,000	$ 1,740,000	$ 184,000