Segment Reporting Revenues Related to Operations in Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Revenues:
Total revenues	$ 322,516	$ 290,516	$ 804,499	$ 843,721
UNITED STATES
Revenues:
Total revenues	139,251	115,984	328,931	360,773
Europe
Revenues:
Total revenues	63,065	65,645	165,529	181,484
Japan
Revenues:
Total revenues	21,651	32,947	83,163	69,888
Asia
Revenues:
Total revenues	94,183	72,186	217,292	219,773
Americas
Revenues:
Total revenues	$ 4,366	$ 3,754	$ 9,584	$ 11,803