CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 27,353	$ 53,372
Trade receivables, net	16,329	15,595
Inventories	12,395	10,764
Prepaid expenses and other current assets	772	1,207
Total current assets	56,849	80,938
Property, plant and equipment, at cost	242,187	236,740
Less accumulated depreciation and depletion	(125,804)	(115,422)
Property, plant and equipment, net	116,383	121,318
Other assets, net	258	302
Total assets	173,490	202,558
Current liabilities:
Current installments of debt	6,250	6,250
Accounts payable	6,103	5,392
Accrued expenses	4,000	4,376
Total current liabilities	16,353	16,018
Debt, excluding current installments	22,917	26,667
Deferred tax liabilities, net	14,441	12,497
Other liabilities	3,690	4,363
Total liabilities	57,401	59,545
Stockholders' equity:
Common stock	647	645
Additional paid-in capital	18,094	17,199
Accumulated other comprehensive loss	(2,663)	(3,001)
Retained earnings	149,541	136,910
Less treasury stock, at cost	(49,530)	(8,740)
Total stockholders' equity	116,089	143,013
Total liabilities and stockholders' equity	$ 173,490	$ 202,558