Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Raw materials and work in process	$ 64,333	$ 63,216
Supplies and service parts	75,053	68,600
Finished products	74,653	71,958
Inventory at FIFO cost	214,039	203,774
Excess of FIFO cost over LIFO cost	(26,957)	(25,175)
Total inventory, net	$ 187,082	$ 178,599