Revenues Related to Operations in Geographic Regions (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Revenues:
Total revenues	$ 1,014,638	$ 914,753	$ 802,727
United States
Revenues:
Total revenues	397,801	386,265	320,244
Other North America
Revenues:
Total revenues	18,361	14,787	22,542
North America
Revenues:
Total revenues	416,162	401,052	342,786
Europe
Revenues:
Total revenues	247,079	223,156	205,512
Japan
Revenues:
Total revenues	116,469	124,298	120,344
Pacific Rim
Revenues:
Total revenues	$ 234,928	$ 166,247	$ 134,085