CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 15,767	$ 23,589
Marketable securities	18,327	11,319
Trade accounts receivable, less allowance of $571 in 2013 and $592 in 2012	10,264	8,946
Inventories	15,588	15,382
Deferred income tax asset	1,006	1,008
Refundable income taxes		290
Prepaid expenses and other current assets	1,067	1,014
TOTAL CURRENT ASSETS	62,019	61,548
Property and equipment, net	31,846	32,370
Intangible assets, net	10,125	11,020
Deferred income tax asset	1,067	717
Other assets	70	70
TOTAL ASSETS	105,127	105,725
CURRENT LIABILITIES
Accounts payable	1,895	1,622
Accrued salaries, wages and payroll taxes	1,826	2,929
Income taxes payable	23
Other current liabilities	1,014	1,020
TOTAL CURRENT LIABILITIES	4,758	5,571
Long-term borrowings	22,000	22,000
Asset retirement obligations	887	871
Other long-term liabilities	292	356
TOTAL LIABILITIES	27,937	28,798
COMMITMENTS AND CONTINGENCIES
SHAREHOLDERS' EQUITY
Common stock, authorized 100,000 shares of $0.01 par value, issued 35,812 in 2013 and 34,829 in 2012	358	348
Additional paid-in capital	75,995	75,708
Retained earnings	11,198	11,232
Accumulated other comprehensive gain	21	21
Common stock in treasury, at cost - 4,762 shares	(10,382)	(10,382)
TOTAL SHAREHOLDERS' EQUITY	77,190	76,927
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 105,127	$ 105,725