STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows From Operating Activities
Net income	$ 9,959	$ 7,084
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,696	5,611
Provision for doubtful accounts	(5)	(20)
Deferred income taxes	274	109
Stock compensation expense	380	318
Loss on disposal of property, plant and equipment		336
Changes in cash due to changes in operating assets and liabilities:
Accounts receivable	(2,490)	(1,487)
Inventories	(1,527)	(1,288)
Income taxes receivable	(456)	285
Prepaid expenses	(492)	(469)
Other current assets	44	292
Accounts payable	(373)	483
Accrued liabilities	708	511
Net cash provided by operating activities	11,718	11,765
Cash Flows From Investing Activities
Purchases of property, plant and equipment	(7,564)	(4,314)
Purchases of short-term investments	(6)	(3,004)
Net cash used in investing activities	(7,570)	(7,318)
Cash Flows From Financing Activities
Principal payments on long-term debt	(864)	(864)
Dividends paid to stockholders	(7,893)	(4,533)
Proceeds from the exercise of stock options	2,942	384
Excess tax benefit of stock options exercised	963	24
Net cash used in financing activities	(4,852)	(4,989)
Net decrease in cash	(704)	(542)
Cash, beginning	5,734	4,297
Cash, ending	5,030	3,755
Supplemental Disclosure:
Interest paid	279	307
Income taxes paid	2,753	2,443
Tax benefits realized from stock options exercised	$ 329	$ 29