Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues
Lime and limestone operations	$ 131,404	$ 129,704	$ 125,169
Natural gas interests	7,121	12,878	7,425
Total revenues	138,525	142,582	132,594
Labor and other operating expenses
Lime and limestone operations	88,346	85,367	81,825
Natural gas interests	1,891	2,269	1,421
Depreciation, depletion and amortization	14,850	13,597	13,307
Total cost of revenues	105,087	101,233	96,553
Gross profit	33,438	41,349	36,041
Selling, general and administrative expenses, including depreciation and amortization expense of $194, $184 and $304 in 2012, 2011 and 2010, respectively	9,193	8,846	8,376
Operating profit	24,245	32,503	27,665
Other expense (income):
Interest expense	2,163	2,495	2,715
Other, net	(19)	(136)	(108)
Total other expense (income)	2,144	2,359	2,607
Income before income taxes	22,101	30,144	25,058
Income tax expense	5,678	7,958	7,018
Net income	$ 16,423	$ 22,186	$ 18,040
Net income per share of common stock:
Basic (in dollars per share)	$ 2.88	$ 3.50	$ 2.82
Diluted (in dollars per share)	$ 2.87	$ 3.49	$ 2.81