Basis of Presentation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Basis of Presentation (Details) [Abstract]
Standard perpetual license sales, minimum term of maintenance agreement (in years)	1Y		1Y
Multi-product contracts, minimum term of maintenance agreement (in years)	2Y		2Y
Multi-product contracts, maximum term of maintenance agreement (in years)	5Y		5Y
Minimum term over which maintenance fees ratably recognized (in years)	1Y		1Y
Maximum term over which maintenance fees ratably recognized (in years)	5Y		5Y
Research and development costs	$ 21.1	$ 18.1	$ 39.6	$ 35.4
Effective tax rate (in hundredths)			32.50%	40.50%
Reduction to income tax provision			5.0
Valuation allowance		$ 2.2		$ 2.2

The maximum period, in years, over which maintenance fees are ratably recognized. Generally, this directly correlates to the term of the maintenance agreement.

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The minimum period, in years, over which maintenance fees are ratably recognized. Generally, this directly correlates to the term of the maintenance agreement.

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The maximum period, in years, for a maintenance agreement included in a large multi-year, multi-product contract.

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The minimum period, in years, for a maintenance agreement included in a large multi-year, multi-product contract.

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The minimum period, in years, for a maintenance agreement included in most standard perpetual license sales.

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- Definition

The sum of the portions of deferred tax assets as of the balance sheet date for which, based on the weight of available evidence, it is more likely than not will not be realized through future reductions of tax-based income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 109

-Paragraph 17

-Subparagraph e

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-Number 109

-Paragraph 43-49

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

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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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 12

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-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(2))

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-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Subparagraph 2

-Article 4

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in the valuation allowance for deferred tax assets in the period.

+ References

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- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 985

-SubTopic 20

-Section 50

-Paragraph 1

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-Number 141

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