Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental cash flow information
Interest	$ 948	$ 1,495	$ 1,746
Income taxes	4,152	5,870	3,750
Revenue Recognition
External freight billed to customers included in revenue	23,219	27,055	25,536
Additions and write-offs to the company's allowance for doubtful accounts
Beginning balance	350	238
Additions	63	148
Write-offs	(13)	(36)
Ending balance	400	350	$ 238
Lime and limestone inventories:
Raw materials	6,627	5,693
Finished goods	2,049	2,283
Total	8,676	7,976
Service parts inventories	6,052	5,460
Total inventories	$ 14,728	13,436
Recurring | Fair value | Cash flows approach
Fair Values of Financial Instruments
Interest rate swap liabilities		(661)
Recurring | Significant Other Observable Inputs (Level 2) | Cash flows approach
Fair Values of Financial Instruments
Interest rate swap liabilities		$ (661)