CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities:
Net income	$ 5,377	$ 6,858
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,718	1,572
Deferred income taxes	(23)	191
Stock-based compensation	286	142
Net Cash Provided By Used In Operating Activities Before Changes In Operating Capital	7,358	8,763
Changes in operating assets and liabilities:
Accounts receivable	(1,160)	(3,364)
Inventories	(1,062)	(1,365)
Prepaid expenses	1,448	162
Other non-current assets	(132)	56
Accounts payable and accrued liabilities	(2,213)	89
Accrued income and other taxes	699	3,003
Other non-current liabilities	6	28
Net Cash Provided by (Used in) Operating Activities, Total	4,944	7,372
Cash flows from investing activities:
Property, plant and equipment additions	(2,722)	(1,906)
Purchase of investments	(9,009)	(9,527)
Proceeds from maturities of investments	4,000	2,400
Net change in accrued interest, premiums, and discounts on investments	113	(202)
Net Cash Provided by (Used in) Investing Activities, Total	(7,618)	(9,235)
Cash flows from financing activities:
Shares tendered for employees' taxes on stock-based compensation	(380)
Purchase of treasury stock	(2,026)
Tax benefit related to stock-based compensation	418
Dividends paid	(985)	(847)
Net Cash Provided by (Used in) Financing Activities, Total	(2,973)	(847)
Net change in cash and cash equivalents	(5,647)	(2,710)
Cash and cash equivalents at beginning of period	24,590	10,670
Cash and cash equivalents at end of period	18,943	7,960
Cash paid for:
Income taxes	$ 418	$ 270