Condensed Consolidated Balance Sheets (unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 149,090	$ 144,737
Accounts receivable, net	45,678	41,999
Inventories	23,805	20,693
Prepaid expenses	2,222	3,048
Prepaid income taxes	0	326
Deferred income taxes	694	593
Other current assets	447	513
Total current assets	221,936	211,909
Property, plant and equipment, net	54,181	52,725
Goodwill	28,515	28,515
Intangible assets with finite lives, net	17,894	18,858
Other assets	537	538
Total assets	323,063	312,545
Current liabilities:
Trade accounts payable	12,201	14,276
Accrued expenses	11,977	11,820
Accrued compensation and other benefits	2,065	4,138
Income taxes payable	123	0
Total current liabilities	26,366	30,234
Deferred income taxes	5,316	5,868
Other long-term obligations	3,310	3,431
Total liabilities	34,992	39,533
Commitments and contingencies (note 12)
Stockholders' equity:
Preferred stock, $25 par value. Authorized 2,000,000 shares; none issued and outstanding	0	0
Common stock, $.0667 par value. Authorized 60,000,000 shares; 29,657,701 shares issued and outstanding at March 31, 2013 and 29,454,171 shares issued and outstanding at December 31, 2012	1,977	1,964
Additional paid-in capital	61,822	57,198
Retained earnings	225,543	214,609
Accumulated other comprehensive loss	(1,271)	(759)
Total stockholders' equity	288,071	273,012
Total liabilities and stockholders' equity	$ 323,063	$ 312,545