CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues
Total revenues	$ 43,559	$ 35,272	$ 120,312	$ 109,801
Cost of revenues
Labor and other operating expenses	25,887	23,687	75,927	73,077
Depreciation, depletion and amortization	4,189	4,389	12,482	12,854
Total cost of revenues	30,076	28,076	88,409	85,931
Gross profit	13,483	7,196	31,903	23,870
Selling, general and administrative expenses	2,928	2,790	8,240	7,856
Operating profit	10,555	4,406	23,663	16,014
Other (income) expense
Interest expense	61	66	183	191
Interest and other income, net	(477)	(495)	(1,459)	(1,307)
Total other (income) expense	(416)	(429)	(1,276)	(1,116)
Income before income tax expense	10,971	4,835	24,939	17,130
Income tax expense	1,069	281	3,876	1,676
Net income	$ 9,902	$ 4,554	$ 21,063	$ 15,454
Net income per share of common stock
Basic (in dollars per share)	$ 1.76	$ 0.81	$ 3.75	$ 2.76
Diluted (in dollars per share)	$ 1.76	$ 0.81	$ 3.75	$ 2.76
Lime and limestone operations
Revenues
Total revenues	$ 43,265	$ 34,713	$ 119,311	$ 107,984
Natural gas interests
Revenues
Total revenues	$ 294	$ 559	$ 1,001	$ 1,817