Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Lime and limestone inventories:
Raw materials	$ 5,621	$ 3,540
Finished goods	1,531	2,107
Total	7,152	5,647
Service parts inventories	5,243	5,117
Total inventories	$ 12,395	$ 10,764