CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS Percentage	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues
Lime and limestone operations (as a percent)	96.20%	95.40%	95.80%	94.90%
Natural gas interests (as a percent)	3.80%	4.60%	4.20%	5.10%
Total revenues (as a percent)	100.00%	100.00%	100.00%	100.00%
Cost of revenues:
Labor and other operating expenses (as a percent)	65.60%	66.30%	66.00%	66.00%
Depreciation, depletion and amortization (as a percent)	9.70%	11.00%	10.50%	10.30%
Total cost of revenues (as a percent)	75.30%	77.30%	76.50%	76.30%
Gross profit (as a percent)	24.70%	22.70%	23.50%	23.70%
Selling, general and administrative expenses (as a percent)	6.00%	6.10%	6.40%	6.30%
Operating profit (as a percent)	18.70%	16.60%	17.10%	17.40%
Other expense (income):
Interest expense (as a percent)	1.20%	1.50%	1.30%	1.60%
Other, net (as a percent)	0.20%	0.00%	0.00%	(0.10%)
Total other expense (income) (as a percent)	1.40%	1.50%	1.30%	1.50%
Income before income taxes (as a percent)	17.30%	15.10%	15.70%	15.90%
Income tax expense (as a percent)	4.30%	3.50%	4.00%	4.10%
Net income (as a percent)	13.00%	11.60%	11.70%	11.80%