Inventories (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2014	Jan. 31, 2014	Oct. 31, 2013
Inventory Disclosure [Abstract]
Finished goods	$ 429,531	$ 350,627	$ 314,780
Raw materials and work-in-process	6,836	9,012	8,554
Inventories	$ 436,367	$ 359,639	$ 323,334