Intangible Assets, by Major Class (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	$ 689,071,000		$ 689,071,000		$ 138,943,000
Accumulated Amortization	(81,944,000)		(81,944,000)		(48,507,000)
Net Amount	607,127,000		607,127,000		90,436,000
Minimum expected useful life of finite lived intangible assets (in years)			1
Maximum expected useful life of finite lived intangible assets (in years)			15
Amortization of Intangible Assets	28,900,000	3,200,000	33,400,000	6,500,000
Future Amortization Expense, Remainder of Fiscal Year			82,147,000
Future Amortization Expense, Year One			102,763,000
Future Amortization Expense, Year Two			137,477,000
Future Amortization Expense, Year Three			88,724,000
Future Amortization Expense, Year Four			56,958,000
Developed Technology [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	353,309,000		353,309,000		94,681,000
Accumulated Amortization	(46,199,000)		(46,199,000)		(35,920,000)
Net Amount	307,110,000		307,110,000		58,761,000
Acquired Finite-lived Intangible Asset, Amount	258,600,000		258,600,000
Weighted average useful life of finite lived intangible assets (in years)			11
Customer Relationships [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	194,500,000		194,500,000		20,400,000
Accumulated Amortization	(22,722,000)		(22,722,000)		(4,633,000)
Net Amount	171,778,000		171,778,000		15,767,000
Acquired Finite-lived Intangible Asset, Amount	174,100,000		174,100,000
Weighted average useful life of finite lived intangible assets (in years)			5
Trademarks and trade names [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	15,730,000		15,730,000		1,730,000
Accumulated Amortization	(1,585,000)		(1,585,000)		(684,000)
Net Amount	14,145,000		14,145,000		1,046,000
Acquired Finite-lived Intangible Asset, Amount	14,000,000		14,000,000
Weighted average useful life of finite lived intangible assets (in years)			5
Backlog [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	24,610,000		24,610,000		2,410,000
Accumulated Amortization	(6,254,000)		(6,254,000)		(2,410,000)
Net Amount	18,356,000		18,356,000		0
Acquired Finite-lived Intangible Asset, Amount	22,200,000		22,200,000
Weighted average useful life of finite lived intangible assets (in years)			1
In-process technology [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	95,286,000		95,286,000		14,086,000
Accumulated Amortization	0		0		0
Net Amount	95,286,000		95,286,000		14,086,000
Acquired Finite-lived Intangible Asset, Amount	81,200,000		81,200,000
Distribution rights [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	5,236,000		5,236,000		5,236,000
Accumulated Amortization	(4,917,000)		(4,917,000)		(4,660,000)
Net Amount	319,000		319,000		576,000
Covenants not to compete [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount	400,000		400,000		400,000
Accumulated Amortization	(267,000)		(267,000)		(200,000)
Net Amount	$ 133,000		$ 133,000		$ 200,000