CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Net sales	$ 571,982	$ 402,938	$ 400,575
Cost of product sales	365,337	295,078	298,956
Gross profit	206,645	107,860	101,619
Operating expenses:
Selling, general and administrative	74,325	61,940	65,643
Research and development	12,446	11,692	12,258
Acquisition related (credit) charge	(17,298)	1,567	(768)
Restructuring - plant closure and severance	914	3,505	12,924
Goodwill impairment	7,797	0	3,832
Total operating expenses	78,184	78,704	93,889
Operating income	128,461	29,156	7,730
Other income (expense)
Interest income	3,991	5,355	4,091
Interest expense	(6,620)	(6,247)	(7,119)
Gain on early extinguishment of debt	0	0	1,881
Gain (loss) on auction rate securities	630	(978)	(5,187)
Miscellaneous, net	1,494	1,085	(979)
Other income (expense) total, net	(505)	(785)	(7,313)
Income before provision (benefit) for income taxes	127,956	28,371	417
Provision (benefit) for income taxes	44,068	(905)	(8,098)
Net income	$ 83,888	$ 29,276	$ 8,515
Net income per common share:
Basic (in dollars per share)	$ 3.41	$ 1.16	$ 0.33
Diluted (in dollars per share)	$ 3.39	$ 1.15	$ 0.33
Shares used in computing per common share amounts:
Basic (in shares)	24,613,825	25,190,985	25,683,963
Diluted (in shares)	24,786,106	25,370,229	25,802,244