Income Taxes (Details) (USD $)	3 Months Ended	6 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010	Jan. 31, 2011
Income Taxes
Income tax provision	$ 50,015,000	$ 2,604,000	$ 57,440,000	$ 2,226,000
Effective tax rate			182.00%	2.20%
Unrecognized tax benefits, if recognized would impact effective tax rate	136,600,000		136,600,000
Amount unrecognized tax benefits could decrease in the next twelve months as a result of settlement of certain tax audits or lapses of statutes of limitation	10,700,000		10,700,000
Interest and penalties related to uncertain tax positions	1,300,000	1,900,000
Accrued interest and penalties	$ 57,000,000		$ 57,000,000		$ 54,900,000

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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- Definition

This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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