Goodwill & Intangible Assets (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
	Dec. 31, 2011 years	Sep. 30, 2011	Mar. 31, 2011	Dec. 31, 2011 Acquired Software And Core Technology [Member]	Dec. 31, 2011 Acquired Software And Core Technology [Member] years	Dec. 31, 2011 Other Acquired Intangible Assets [Member]	Dec. 31, 2010 Other Acquired Intangible Assets [Member]	Dec. 31, 2011 Other Acquired Intangible Assets [Member]	Dec. 31, 2010 Other Acquired Intangible Assets [Member]	Dec. 31, 2010 Acquired Software [Member]	Dec. 31, 2010 Acquired Software [Member]	Dec. 31, 2011 Customer Relationships [Member] years
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 169,952	$ 141,356	$ 128,177
Intangible assets, net	56,390		47,686
Amortization expenses included in cost of product				$ 1,200	$ 3,400	$ 565	$ 476	$ 1,600	$ 1,400	$ 1,000	$ 3,000
Weighted average useful life in years of acquired intangible assets	10.8				6.3							15.2