Segment Reporting Revenues Related to Operations in Geographic Regions (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Revenues:
Total revenues	$ 254,344	$ 281,062	$ 481,983	$ 553,205
UNITED STATES
Revenues:
Total revenues	106,460	115,598	189,680	244,789
Europe
Revenues:
Total revenues	47,590	69,520	102,464	115,839
Japan
Revenues:
Total revenues	23,580	15,524	61,512	36,941
Asia
Revenues:
Total revenues	74,142	77,458	123,109	147,587
Americas
Revenues:
Total revenues	$ 2,572	$ 2,962	$ 5,218	$ 8,049