Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes
Current income tax expense	$ 4,822	$ 5,282	$ 3,240
Deferred income tax expense	(227)	1,273	1,793
Income tax expense	4,595	6,555	5,033
Amount
Income taxes computed at the federal statutory rate	6,118	9,073	6,942
(Reduction) increase in taxes resulting from:
Statutory depletion in excess of cost depletion	(1,708)	(2,139)	(1,965)
Manufacturing deduction	(548)	(574)	(299)
State income taxes, net of federal income tax benefit	309	104	132
Other	424	91	223
Income tax expense	$ 4,595	$ 6,555	$ 5,033
Percent of Pretax Income
Income taxes computed at the federal statutory rate (as a percent)	35.00%	35.00%	35.00%
(Reduction) increase in taxes resulting from (as a percent):
Statutory depletion in excess of cost depletion (as a percent)	(9.80%)	(8.20%)	(9.90%)
Manufacturing deduction (as a percent)	(3.10%)	(2.20%)	(1.50%)
State income taxes, net of federal income tax benefit (as a percent)	1.80%	0.40%	0.70%
Other (as a percent)	2.40%	0.30%	1.10%
Income tax expense (as a percent)	26.30%	25.30%	25.40%
Deferred tax liabilities
Lime and limestone property, plant and equipment	$ 18,833	$ 20,089
Natural gas interests drilling costs and equipment	3,101	3,387
Other		292
Total	21,934	23,768
Deferred tax assets
Alternative minimum tax credit carry forwards	2,259	3,887
Minimum pension liability		346
Fair value liability of interest rate hedges		240
Other	491	470
Total	2,750	4,943
Deferred tax liabilities, net, Total	19,184	18,825
Current income taxes:
Prepaid expenses and other current assets	286	881
Deferred income taxes:
Deferred tax liabilities, net	19,184	$ 18,825
Federal
Operating loss carry forwards
Net operating loss carryforwards	$ 0