Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Lime and limestone operations	$ 128,390	$ 144,567	$ 128,003
Natural gas interests	2,447	5,274	5,762
Total revenues	130,837	149,841	133,765
Labor and other operating expenses
Lime and limestone operations	85,080	96,798	86,754
Natural gas interests	1,259	1,546	1,920
Depreciation, depletion and amortization	15,784	14,706	14,291
Total cost of revenues	102,123	113,050	102,965
Gross profit	28,714	36,791	30,800
Selling, general and administrative expenses, including depreciation and amortization expense of $249, $197 and $207 in 2015, 2014 and 2013, respectively	9,628	9,469	9,149
Operating profit	19,086	27,322	21,651
Other expenses (income):
Interest expense	1,036	1,529	1,852
Other expense (income), net	569	(129)	(34)
Total other expense (income)	1,605	1,400	1,818
Income before income taxes	17,481	25,922	19,833
Income tax expense	4,595	6,555	5,033
Net income	$ 12,886	$ 19,367	$ 14,800
Income per share of common stock:
Basic (in dollars per share)	$ 2.30	$ 3.47	$ 2.66
Diluted (in dollars per share)	2.30	3.47	$ 2.66
Cash dividends per share of common stock (in dollars per share)	$ 0.50	$ 0.50