Acquisitions of and Investments in Businesses and Technologies Changes in the net carrying value of the investment in SST (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Balance at beginning of year	$ 4,409	$ 4,728
Income from equity investment	156	156	195
Balance at end of year	4,063	4,409	4,728
SST [Member]
Investments in and Advances to Affiliates, at Fair Value [Roll Forward]
Balance at beginning of year	4,409	4,728	5,010
Acquisition				5,000
Income from equity investment	156	156	195
Amortization of intangible assets	(477)	(475)	(477)
Proceeds from Equity Method Investment, Dividends or Distributions	(25)	0	0
Balance at end of year	$ 4,063	$ 4,409	$ 4,728	$ 5,010