Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Raw materials and work in process	$ 66,221	$ 63,216
Supplies and service parts	72,551	68,600
Finished products	68,335	71,958
Inventory at FIFO cost	207,107	203,774
Excess of FIFO cost over LIFO cost	(27,429)	(25,175)
Total inventory, net	$ 179,678	$ 178,599