CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS Percentage	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues
Lime and limestone operations (as a percent)	95.50%	94.10%
Natural gas interests (as a percent)	4.50%	5.90%
Total revenues (as a percent)	100.00%	100.00%
Cost of revenues:
Labor and other operating expenses (as a percent)	68.50%	64.60%
Depreciation, depletion and amortization (as a percent)	11.60%	9.90%
Total cost of revenues (as a percent)	80.10%	74.50%
Gross profit (as a percent)	19.90%	25.50%
Selling, general and administrative expenses (as a percent)	6.80%	6.30%
Operating profit (as a percent)	13.10%	19.20%
Other expense (income):
Interest expense (as a percent)	1.50%	1.60%
Other, net (as a percent)	(0.10%)	0.10%
Total other expense (income) (as a percent)	1.40%	1.70%
Income before income taxes (as a percent)	11.70%	17.50%
Income tax expense (as a percent)	3.00%	4.70%
Net income (as a percent)	8.70%	12.80%