Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Lime and limestone operations	$ 137,190	$ 128,390	$ 144,567
Natural gas interests	2,092	2,447	5,274
Total revenues	139,282	130,837	149,841
Labor and other operating expenses
Lime and limestone operations	89,095	85,080	96,798
Natural gas interests	1,164	1,259	1,546
Depreciation, depletion and amortization	15,931	15,784	14,706
Total cost of revenues	106,190	102,123	113,050
Gross profit	33,092	28,714	36,791
Selling, general and administrative expenses, including depreciation and amortization expense of $210, $249 and $197 in 2016, 2015 and 2014, respectively	9,612	9,628	9,469
Operating profit	23,480	19,086	27,322
Other expenses (income):
Interest expense	246	1,036	1,529
Other (income) expense, net	(384)	569	(129)
Total other expense (income)	(138)	1,605	1,400
Income before income taxes	23,618	17,481	25,922
Income tax expense	5,864	4,595	6,555
Net income	$ 17,754	$ 12,886	$ 19,367
Net income per share of common stock:
Basic (in dollars per share)	$ 3.19	$ 2.30	$ 3.47
Diluted (in dollars per share)	3.19	2.30	3.47
Cash dividends per share of common stock (in dollars per share)	$ 0.50	$ 0.50	$ 0.50