Inventories (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw materials and work in process	$ 41,338	$ 33,920
Supplies and service parts	37,472	48,165
Finished products	31,037	38,515
Inventory at FIFO cost	109,847	120,600
Excess of FIFO cost over LIFO cost	(14,968)	(17,020)
Total inventory, net	$ 94,879	$ 103,580