Segment Reporting Revenues Related to Operations in Geographic Regions (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
Revenues:
Total revenues	$ 260,233	$ 253,216	$ 512,384	$ 479,731
UNITED STATES
Revenues:
Total revenues	111,692	91,527	236,458	187,613
Europe
Revenues:
Total revenues	55,462	45,701	115,611	94,408
Japan
Revenues:
Total revenues	20,973	16,477	42,254	43,154
Asia
Revenues:
Total revenues	62,963	94,451	106,676	146,442
Americas [Member]
Revenues:
Total revenues	$ 9,143	$ 5,060	$ 11,385	$ 8,114