Goodwill, Capitalized Software and Other Intangible Assets (Details) (USD $)	3 Months Ended			9 Months Ended
	Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2011		Dec. 31, 2010	Mar. 31, 2011
Goodwill [Line Items]
Goodwill as of beginning of period				$ 607,765,000
Acquisition				210,908,000	[1]
Effect of foreign currency translation				(21,510,000)
Goodwill as of end of period	797,163,000			797,163,000
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, amortized intangible assets	449,428,000			449,428,000			391,214,000
Accumulated Amortization	(336,678,000)			(336,678,000)			(312,680,000)
Net Carrying Amount, amortized intangible assets	112,750,000			112,750,000			78,534,000
Amortization expense of finite-lived intangible assets [Abstract]
Amortization Expense	8,290,000		5,659,000	22,215,000		16,592,000
Future amortization expense of finite-lived intangible assets [Abstract]
Future amortization expense, year one				30,069,000
Future amortization expense, year two				29,521,000
Future amortization expense, year three				25,516,000
Future amortization expense, year four				17,736,000
Future amortization expense, year five				14,379,000
Thereafter				17,744,000
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	42,000,000			42,000,000
Customer Relationship [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	3,700,000			3,700,000
Developed Technology Rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	28,500,000			28,500,000
Other Acquired Developed Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	4,200,000			4,200,000
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	9,800,000			9,800,000
Capitalized Software [Member]
Future amortization expense of finite-lived intangible assets [Abstract]
Future amortization expense, year one				21,808,000
Future amortization expense, year two				21,926,000
Future amortization expense, year three				18,414,000
Future amortization expense, year four				12,880,000
Future amortization expense, year five				10,258,000
Thereafter				3,321,000
Amortization period (in years)	5
Capitalized Software [Member] | Internally Developed [Member]
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, amortized intangible assets	208,959,000			208,959,000			194,770,000
Accumulated Amortization	(171,162,000)			(171,162,000)			(161,671,000)
Net Carrying Amount, amortized intangible assets	37,797,000			37,797,000			33,099,000
Amortization expense of finite-lived intangible assets [Abstract]
Amortization Expense	3,323,000		2,806,000	9,483,000		8,250,000
Capitalized Software [Member] | Purchased [Member]
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, amortized intangible assets	166,142,000	[2]		166,142,000	[2]		136,469,000
Accumulated Amortization	(131,253,000)	[2]		(131,253,000)	[2]		(125,118,000)
Net Carrying Amount, amortized intangible assets	34,889,000	[2]		34,889,000	[2]		11,351,000
Amortization expense of finite-lived intangible assets [Abstract]
Amortization Expense	2,711,000		1,200,000	6,438,000		3,535,000
Customer Relationship [Member]
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, amortized intangible assets	51,979,000	[3]		51,979,000	[3]		48,813,000
Accumulated Amortization	(19,982,000)	[3]		(19,982,000)	[3]		(16,729,000)
Net Carrying Amount, amortized intangible assets	31,997,000	[3]		31,997,000	[3]		32,084,000
Amortization expense of finite-lived intangible assets [Abstract]
Amortization Expense	1,164,000		1,163,000	3,427,000		3,382,000
Future amortization expense of finite-lived intangible assets [Abstract]
Future amortization expense, year one				4,470,000
Future amortization expense, year two				4,168,000
Future amortization expense, year three				4,121,000
Future amortization expense, year four				4,121,000
Future amortization expense, year five				4,121,000
Thereafter				14,423,000
Amortization period (in years)	10
Others [Member]
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, amortized intangible assets	22,348,000	[3]		22,348,000	[3]		11,162,000
Accumulated Amortization	(14,281,000)	[3]		(14,281,000)	[3]		(9,162,000)
Net Carrying Amount, amortized intangible assets	8,067,000	[3]		8,067,000	[3]		2,000,000
Amortization expense of finite-lived intangible assets [Abstract]
Amortization Expense	1,092,000		490,000	2,867,000		1,425,000
Future amortization expense of finite-lived intangible assets [Abstract]
Future amortization expense, year one				3,791,000
Future amortization expense, year two				3,427,000
Future amortization expense, year three				2,981,000
Future amortization expense, year four				735,000
Future amortization expense, year five				0
Thereafter				0
Amortization period (in years)	3
Trademarks [Member]
Capitalized Software and Other Intangible Assets [Abstract]
Gross Carrying Amount, unamortized intangible assets	4,425,000			4,425,000			4,467,000
Net Carrying Amount, unamortized intangible assets	4,425,000			4,425,000			4,467,000
Application Performance Management [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				282,815,000
Acquisition				210,908,000	[1]
Effect of foreign currency translation				(21,017,000)
Goodwill as of end of period	472,706,000			472,706,000
Excess of the estimated fair value over the carrying value of the reporting unit (in hundredths)	59.00%			59.00%
Mainframe [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				141,020,000
Acquisition				0	[1]
Effect of foreign currency translation				(130,000)
Goodwill as of end of period	140,890,000			140,890,000
Changepoint [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				22,151,000
Acquisition				0	[1]
Effect of foreign currency translation				(20,000)
Goodwill as of end of period	22,131,000			22,131,000
Uniface [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				21,350,000
Acquisition				0	[1]
Effect of foreign currency translation				(20,000)
Goodwill as of end of period	21,330,000			21,330,000
Professional Services [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				115,044,000
Acquisition				0	[1]
Effect of foreign currency translation				(323,000)
Goodwill as of end of period	114,721,000			114,721,000
Application Services [Member]
Goodwill [Line Items]
Goodwill as of beginning of period				25,385,000
Acquisition				0	[1]
Goodwill as of end of period	25,385,000			25,385,000
Products [Member]
Goodwill [Line Items]
Goodwill as of beginning of period							221,100,000
Goodwill as of end of period							221,100,000
Web Performance Services [Member]
Goodwill [Line Items]
Goodwill as of beginning of period							219,500,000
Goodwill as of end of period							219,500,000
Former Professional Services [Member]
Goodwill [Line Items]
Goodwill as of beginning of period							141,800,000
Goodwill as of end of period							$ 141,800,000

[1] The Company acquired dynaTrace on July 1, 2011. See Note 2 for information related to the purchase accounting that resulted in the recording of goodwill.

[2] In July 2011, the Company acquired developed technology valued at $28.5 million as part of the dynaTrace acquisition (see Note 2 for additional information). Additionally, the Company acquired developed technology valued at $4.2 million during fiscal 2012.

[3] In July 2011, the Company acquired customer relationship agreements valued at $3.7 million and trade names valued at $9.8 million as part of the dynaTrace acquisition (see Note 2 for additional information).