Inventories (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Inventories carried at LIFO:
Finished goods	$ 36,238	$ 33,546
Raw materials, production parts and work-in-process	13,922	14,291
LIFO Reserve	(27,463)	(27,608)
Total LIFO inventories	22,697	20,229
Inventories carried at FIFO:
Finished goods	31,489	25,623
Raw materials, production parts and work-in-process	12,720	12,284
Total FIFO inventories	44,209	37,907
Inventories	$ 66,906	$ 58,136