CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS Percentage	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues
Lime and limestone operations (as a percent)	98.40%	96.90%	98.00%	96.30%
Natural gas (as a percent)	1.60%	3.10%	2.00%	3.70%
Total revenues (as a percent)	100.00%	100.00%	100.00%	100.00%
Cost of revenues:
Labor and other operating expenses (as a percent)	61.30%	65.20%	64.80%	65.20%
Depreciation, depletion and amortization (as a percent)	10.70%	9.50%	11.80%	9.50%
Total cost of revenues (as a percent)	72.00%	74.70%	76.60%	74.70%
Gross profit (as a percent)	28.00%	25.30%	23.40%	25.30%
Selling, general and administrative expenses (as a percent)	6.70%	6.20%	7.30%	6.10%
Operating profit (as a percent)	21.30%	19.10%	16.10%	19.20%
Other expenses (income):
Interest expense (as a percent)	0.10%	0.90%	1.00%	1.00%
Other (income) expense, net (as a percent)	(0.10%)	0.00%	0.70%	0.00%
Total other expense (income) (as a percent)	0.00%	0.90%	1.70%	1.00%
Income before income taxes (as a percent)	21.30%	18.20%	14.40%	18.20%
Income tax expense (as a percent)	6.00%	4.30%	3.80%	4.50%
Net income (as a percent)	15.30%	13.90%	10.60%	13.70%