Income Taxes (Reconciliation of Income Tax Computed at the Federal Statutory Rate to the Company's Effective Income Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Income Tax Disclosure [Abstract]
Tax at U.S. federal statutory rate	35.00%	35.00%	35.00%
State and local income taxes, net of U.S. federal tax benefit	(2.80%)	(0.30%)	1.50%
Tax credit for research activities	(24.20%)	(3.90%)	(1.20%)
Tax benefit on insurance premiums	(10.30%)	(1.00%)	(0.00%)
Tax benefit on qualified production activities	(13.70%)	(3.60%)	(2.90%)
Change in uncertain tax positions	1.80%	0.00%	0.00%
Foreign tax rate difference	(2.90%)	0.40%	0.10%
Other, net	(1.70%)	0.30%	0.10%
Effective income tax rate	(18.80%)	26.90%	32.60%
Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount	$ 560
Favorable prior year tax benefit	989	$ 776
Tax deductible goodwill and long-lived assets	$ 14,756
Discrete tax benefit		$ 963