Revenues Related to Operations in Geographic Regions (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Revenues:
Total revenues	$ 268,760	$ 250,508	$ 757,489	$ 694,283
North America
Revenues:
Total revenues	125,809	116,256	356,472	306,650
Europe
Revenues:
Total revenues	58,937	62,555	165,532	161,394
Japan
Revenues:
Total revenues	23,602	28,793	86,766	96,193
Pacific Rim
Revenues:
Total revenues	$ 60,412	$ 42,904	$ 148,719	$ 130,046