Acquired Intangible Assets (Calculation Of Acquired Intangibles By Asset Class) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Jun. 30, 2013	Jun. 30, 2012
Finite-Lived Intangible Assets, Net [Abstract]
Cost	$ 1,060,820	$ 847,404
Accumulated Amortization	(697,205)	(534,841)
Net	363,615	312,563
Technology Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Cost	557,039	473,008
Accumulated Amortization	(403,126)	(309,517)
Net	153,913	163,491
Weighted-average amortization period (in years) for acquired intangible assets	6 years
Customer Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Cost	503,781	374,396
Accumulated Amortization	(294,079)	(225,324)
Net	$ 209,702	$ 149,072
Weighted-average amortization period (in years) for acquired intangible assets	7 years

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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=7658586&loc=d3e16265-109275

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- Definition

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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