Inventories (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventories carried at LIFO:
Finished goods	$ 44,468	$ 41,687
Raw materials, production parts and work-in-process	25,428	24,458
LIFO Reserve	(28,166)	(28,166)
LIFO Inventory Amount	41,730	37,979
Inventories carried at FIFO:
Finished goods	31,645	29,851
Raw materials, production parts and work-in-process	13,159	12,681
Total FIFO inventories	44,804	42,532
Total Inventories	$ 86,534	$ 80,511