Income Taxes (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
Income Tax Disclosure [Abstract]
Effective tax rate	34.10%	36.10%	37.10%	40.00%
Increase in income tax provision	145.80%		44.20%
Provision for income taxes	$ 20,378	$ 8,291	$ 31,196	$ 21,628
Effective tax rate reconciliation, percentage			35.00%