Income Taxes Income Taxes - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Income Taxes [Line Items]
Deferred Tax Assets Unrecognized Tax Benefits	$ 32,794	$ 28,210
Undistributed Earnings of Foreign Subsidiaries	431,201
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	0
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound	11,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(297)	(677)	211
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	9,538	9,916
Liabilities For Uncertain Tax Positions Current and Noncurrent	28,198
Liability for Uncertain Tax Positions, Current	5,535
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 25,488
Domestic Tax Authority [Member]
Income Taxes [Line Items]
Open Tax Year	2010
Japan [Member]
Income Taxes [Line Items]
Open Tax Year	2008
Ireland [Member]
Income Taxes [Line Items]
Open Tax Year	2009