Description of the Business and Significant Accounting Policies (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Description of the Business and Significant Accounting Policies
Impairment of long-lived asset	$ 0	$ 0	$ 2,128
Commissions
Commission expense	88,500	61,000	54,000
Leases
Lease rent expenses	12,800	10,500	6,400
Advertising Expense
Advertising expenses	$ 13,300	$ 8,400	$ 6,300