Inventories (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Inventories carried at LIFO:
Finished goods	$ 41,598	$ 36,238
Raw materials, production parts and work-in-process	18,525	13,922
LIFO Reserve	(27,463)	(27,463)
LIFO Inventory Amount	32,660	22,697
Inventories carried at FIFO:
Finished goods	32,560	31,489
Raw materials, production parts and work-in-process	13,814	12,720
Total FIFO inventories	46,374	44,209
Total Inventories	$ 79,034	$ 66,906