Foreign and U.S. Federal and State Tax Carryforwards for Income Tax Purposes (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2012
Operating Loss and Tax Credit Carryforward [Line Items]
Foreign net operating loss carryforwards	$ 13,155
Internal Revenue Service (IRS)
Operating Loss and Tax Credit Carryforward [Line Items]
Research & expermination credit carryforward	52,175
Net operating loss carryforward	234,999
Foreign tax credits	4,748
Alternative minimum tax credits	2,683
Childcare credits/ Miscellaneous	1,363
State and Local Jurisdiction
Operating Loss and Tax Credit Carryforward [Line Items]
Research & expermination credit carryforward	11,394
Net operating loss carryforward	200,581
Childcare credits/ Miscellaneous	$ 1,086

The tax effect as of the balance sheet date of the amount of excess of tax deductions over gross income in a year which cannot be used on the tax return of a country outside the country of domicile in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of the carryforward amount to realize the deferred tax asset.

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The tax effect as of the balance sheet date of the amount of future tax deductions arising from unused alternative minimum tax credit carryforwards; a tax credit carryforward is the amount by which tax credits available for utilization exceeded statutory limits on inclusion in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.

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- Definition

The tax effect as of the balance sheet date of the amount of future tax effects arising from unused foreign tax credit carryforwards which will decrease future taxable income if applied in future years; a tax credit carryforward is the amount by which tax credits available for utilization exceeded statutory limits on inclusion in historical filings, and which can only be utilized if sufficient tax-basis income is generated in future periods and providing tax laws continue to allow such utilization.

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