Summary of Significant Accounting Policies - Additional Disclosures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Values of Financial Instruments
Foreign exchange hedges liabilities	$ (352)
Additions and write-offs to the company's allowance for doubtful accounts
Beginning balance	400	$ 350
Additions	293	63
Write-offs	(359)	(13)
Ending balance	334	400	$ 350
Lime and limestone inventories:
Raw materials	4,811	6,627
Finished goods	2,070	2,049
Total	6,881	8,676
Service parts inventories	5,552	6,052
Total inventories	12,433	14,728
Supplemental cash flow information
Interest	113	948	1,495
Income taxes	4,908	4,152	5,870
Revenue Recognition
External freight billed to customers included in revenue	26,568	$ 23,219	$ 27,055
Recurring | Fair value | Cash flows approach
Fair Values of Financial Instruments
Foreign exchange hedges liabilities	(352)
Recurring | Significant Other Observable Inputs (Level 2) | Fair value | Cash flows approach
Fair Values of Financial Instruments
Foreign exchange hedges liabilities	$ (352)