Note 11 - Stock-based Compensation - Weighted Average Assumption to Value SARs (Details) - Stock Appreciation Rights (SARs) [Member]		6 Months Ended
		Jul. 31, 2018	Jul. 31, 2017
Expected life in years (1) (Year)	[1]	5 years 182 days	5 years 182 days
Risk free interest rate (2)	[2]	2.80%	1.82%
Volatility (3)	[3]	31.00%	33.00%
Dividend rate (4)	[4]	0.54%	0.91%

[1] The expected life of SARs granted under the stock-based compensation plans is based on historical vested SAR exercise and post-vest forfeiture patterns and includes an estimate of the expected term for SARs that were fully vested and outstanding.

[2] The risk-free interest rate is based on the U.S. Treasury yield for a term consistent with the expected life of SARs in effect at the time of grant.

[3] The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of the Company's common stock for a period equivalent to the expected life of the SARs, which it believes is representative of the expected volatility over the expected life of the SARs.

[4] The Company expects to continue paying quarterly dividends at the same rate as the six months ending on July 31, 2018.