Intangible Assets and Goodwill (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
Mar. 31, 2012 Y	Mar. 31, 2011	Mar. 31, 2010
Intangible Assets And Goodwill (Textual) [Abstract]
Amortization of acquired technology	$ 55.6	$ 45.5	$ 43.8
Weighted average remaining life of acquired technology and customer relationships	4.1

The average useful life of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar either by their nature or by their use in the operations of a company.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16265-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration