CONDENSED CONSOLIDATED STATEMENTS OF INCOME (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013		Dec. 31, 2012
Income Statement
Net sales	$ 482,372		$ 416,047		$ 1,437,833		$ 1,151,479
Cost of sales	199,652	[1]	215,619	[1]	599,676	[1]	552,059	[1]
Gross profit	282,720		200,428		838,157		599,420
Operating expenses:
Research and development	76,341	[1]	71,377	[1]	227,680	[1]	184,285	[1]
Selling, general and administrative	66,856	[1]	69,368	[1]	201,934	[1]	196,727	[1]
Amortization of acquired intangible assets	21,804		39,711		73,225		71,615
Special charges	801		2,559		2,491		24,953
Total operating expenses	165,802		183,015		505,330		477,580
Operating income	116,918		17,413		332,827		121,840
Losses on equity method investments	150		(229)		(211)		(382)
Other income (expense):
Interest income	4,241		3,813		12,176		11,889
Interest expense	(12,545)		(11,077)		(36,755)		(30,983)
Other income (expense), net	3,824		(228)		6,093		311
Income before income taxes	112,588		9,692		314,130		102,675
Income tax provision (benefit)	7,187		(481)		30,344		34,976
Net income	105,401		10,173		283,786		67,699
Basic net income per common share	$ 0.53		$ 0.05		$ 1.43		$ 0.35
Diluted net income per common share	$ 0.48		$ 0.05		$ 1.31		$ 0.33
Dividends declared per common share	$ 0.3545		$ 0.3520		$ 1.0620		$ 1.0530
Basic common shares outstanding	198,759		194,958		197,845		194,157
Diluted common shares outstanding	219,089		204,405		215,943		204,553
Allocated Share-based Compensation Expense	$ 12,209		$ 11,365		$ 36,874		$ 37,163

[1] Includes share-based compensation expense as follows:Cost of sales 1,841 1,834 5,674 5,758 Research and development 6,141 6,172 18,762 16,562 Selling, general and administrative 5,737 6,114 16,939 22,339