Revenues Related to Operations in Geographic Regions (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012	Apr. 30, 2011
Revenues:
Total revenues	$ 247,918	$ 230,035
North America
Revenues:
Total revenues	129,110	90,323
Europe
Revenues:
Total revenues	52,631	52,197
Japan
Revenues:
Total revenues	24,983	41,634
Pacific Rim
Revenues:
Total revenues	$ 41,194	$ 45,881