Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventories carried at LIFO:
Finished goods	$ 43,753	$ 41,225
Raw materials, production parts and work-in-process	25,670	22,158
LIFO reserve	(27,645)	(27,645)
Total LIFO inventories	41,778	35,738
Inventories carried at FIFO:
Finished goods	31,705	32,421
Raw materials, production parts and work-in-process	13,801	13,812
Inventories held for sale	0	(4,679)
Total FIFO inventories	45,506	41,554
Total inventories	$ 87,284	$ 77,292