Changes in Accrued Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013	Jan. 31, 2014
Accrued special charges [Roll Forward]
Special charges	$ 8,375	$ 4,688	$ 19,409	$ 12,570
Adjustments (payments)			(18,347)
Accrued Special Charges	8,908		8,908		7,846
Litigation costs
Accrued special charges [Roll Forward]
Special charges			15,193
Adjustments (payments)			(13,115)
Accrued Special Charges	6,933		6,933		4,855
Employee severance and related costs
Accrued special charges [Roll Forward]
Special charges			3,077
Adjustments (payments)			(3,014)
Accrued Special Charges	1,067		1,067		1,004
Other costs
Accrued special charges [Roll Forward]
Special charges			1,139
Adjustments (payments)			(2,218)
Accrued Special Charges	$ 908		$ 908		$ 1,987