Changes in Accrued Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013	Jan. 31, 2014
Accrued special charges [Roll Forward]
Special charges	$ 5,108	$ 3,859	$ 11,034	$ 7,882
Adjustments (payments)			(13,561)
Accrued Special Charges	5,319		5,319		7,846
Litigation costs
Accrued special charges [Roll Forward]
Special charges			8,189
Adjustments (payments)			(9,556)
Accrued Special Charges	3,488		3,488		4,855
Employee severance and related costs
Accrued special charges [Roll Forward]
Special charges			1,700
Adjustments (payments)			(1,987)
Accrued Special Charges	717		717		1,004
Other costs
Accrued special charges [Roll Forward]
Special charges			1,145
Adjustments (payments)			(2,018)
Accrued Special Charges	$ 1,114		$ 1,114		$ 1,987