Income Taxes Significant components of the company's income tax provision (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Income Taxes:
Currently payable	$ 26,894	$ 19,705	$ 19,322
Deferred	(1,803)	5,358	423
Income taxes	$ 25,091	$ 25,063	$ 19,745