Segment Reporting Revenues Related to Operations in Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Revenues:
Total revenues	$ 290,516	$ 292,683	$ 843,721	$ 805,067
UNITED STATES
Revenues:
Total revenues	115,984	135,264	360,773	371,722
Europe
Revenues:
Total revenues	65,645	64,936	181,484	180,547
Japan
Revenues:
Total revenues	32,947	25,359	69,888	67,613
Asia
Revenues:
Total revenues	72,186	64,346	219,773	171,022
Americas [Member]
Revenues:
Total revenues	$ 3,754	$ 2,778	$ 11,803	$ 14,163