Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Inventory Disclosure [Abstract]
Raw materials and work in process	$ 70,472	$ 63,216
Supplies and service parts	70,346	68,600
Finished products	64,177	71,958
Inventory at FIFO cost	204,995	203,774
Excess of FIFO cost over LIFO cost	(25,674)	(25,175)
Total inventory, net	$ 179,321	$ 178,599