Segment Reporting Revenues Related to Operations in Geographic Regions (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012
Revenues:
Total revenues	$ 253,216	$ 240,811	$ 479,731	$ 488,729
North America
Revenues:
Total revenues	96,587	101,553	195,727	230,663
Europe
Revenues:
Total revenues	45,701	53,964	94,408	106,595
JAPAN
Revenues:
Total revenues	16,477	38,181	43,154	63,164
Asia
Revenues:
Total revenues	$ 94,451	$ 47,113	$ 146,442	$ 88,307