ACQUISITION (Details) $ / shares in Units, € in Thousands, $ in Thousands			1 Months Ended		12 Months Ended
	Jan. 12, 2016 EUR (€)	Jan. 12, 2016 USD ($)	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) $ / shares	Jan. 12, 2016 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
ACQUISITION
Goodwill				$ 17,757	$ 27,522	$ 17,757		$ 18,303	$ 20,233
Business Acquisition, Pro Forma Information
Revenues						264,793
Net income						$ 12,386
Diluted net income per share (in dollars per share) | $ / shares						$ 1.34
Heidrive
ACQUISITION
Acquisition cost		$ 8,470	€ 20,000	$ 22,000
Seller concession	€ 732	795
Adjustments to purchase price	17,068	18,534
Cash paid for acquisition, net		$ 7,675
Borrowings used to fund acquisition	€ 10,000						$ 10,859
Transaction costs related to acquisition					135	$ 467
Cash							2,329
Other current assets							5,868
Property, plant and equipment							4,002
Amortizable intangible assets					$ 7,710		7,710
Goodwill							10,248
Current liabilities							(7,696)
Long-term liabilities							(3,927)
Net purchase price							$ 18,534