CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Income Statement
Net sales	$ 352,134,000	$ 374,507,000
Cost of sales	149,055,000	154,759,000
Gross profit	203,079,000	219,748,000
Operating expenses:
Research and development	48,826,000	45,298,000
Selling, general and administrative	57,920,000	57,590,000
Total operating expenses	106,746,000	102,888,000
Operating income	96,333,000	116,860,000
Losses on equity method investments	(121,000)	(61,000)
Other income (expense):
Interest income	4,332,000	4,006,000
Interest expense	(9,148,000)	(8,015,000)
Other, net	(532,000)	1,036,000
Income from continuing operations before income taxes	90,864,000	113,826,000
Income tax provision	12,154,000	14,533,000
Net income	$ 78,710,000	$ 99,293,000
Basic net income per common share	$ 0.41	$ 0.52
Diluted net income per common share	$ 0.39	$ 0.49
Dividends declared per common share	$ 0.350	$ 0.346
Basic common shares outstanding	193,452	190,112
Diluted common shares outstanding	203,700	204,567