Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental cash flow information
Interest	$ 1,746	$ 2,069	$ 2,395
Income taxes	3,750	3,000	4,529
Revenue Recognition
External freight billed to customers included in revenue	25,536	26,675	26,470
Additions and write-offs to the company's allowance for doubtful accounts
Beginning balance	525	429
Additions	69	105
Write-offs	(356)	(9)
Ending balance	238	525	429
Lime and limestone inventories:
Raw materials	6,203	6,718
Finished goods	2,284	2,328
Total	8,487	9,046
Service parts inventories	5,201	5,081
Total inventories	13,688	14,127
Recurring | Fair value | Cash flows approach
Fair Values of Financial Instruments
Interest rate swap liabilities	(1,533)	(2,629)
Recurring | Significant Other Observable Inputs (Level 2) | Cash flows approach
Fair Values of Financial Instruments
Interest rate swap liabilities	$ (1,533)	$ (2,629)
3 month LIBOR
Fair Values of Financial Instruments
Variable rate basis	3 month LIBOR