Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	$ 4,391	$ 2,666	$ 2,420
Charged to Costs and Expenses	(361)	1,768	1,183
Charged to Other Accounts	20	1	22
Deductions Describe	(676)	(44)	(959)
Balance at End of Period	3,374	4,391	2,666
Allowance for obsolete equipment and inventory [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Period	901	730	923
Charged to Costs and Expenses	164	175	216
Charged to Other Accounts	8	(4)	(195)
Deductions Describe			(214)
Balance at End of Period	$ 1,073	$ 901	$ 730