Business Segment Information (Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2012		Jan. 31, 2011		Jan. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 405,455	$ 453,078	$ 386,367	$ 349,497	$ 430,837	$ 425,460	$ 410,242	$ 356,888	$ 1,594,397		$ 1,623,427		$ 1,533,937
Revenues by Country, Percent									100.00%		100.00%		100.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									436,380		481,370		459,844
Revenues by Country, Percent									27.00%		30.00%		30.00%
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									86,250		104,281		80,516
Revenues by Country, Percent									5.00%		6.00%		5.00%
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									74,974		46,576		57,270
Revenues by Country, Percent									5.00%		3.00%		4.00%
Other foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 996,793	[1]	$ 991,200	[1]	$ 936,307	[1]
Revenues by Country, Percent									63.00%	[1]	61.00%	[1]	61.00%	[1]
Maximum [Member] | Other foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by Country, Percent									5.00%		5.00%		5.00%

[1] Other foreign consists of numerous countries, none of which represents more than 5% of total revenue in any fiscal year presented.