INCOME TAXES - Tax Effects (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of components of income before income taxes
Domestic	$ 4,288	$ 7,676	$ 9,484
Foreign	8,515	7,745	9,139
Income before income taxes	12,803	15,421	18,623
Current provision (benefit)
Domestic	(70)	1,936	1,917
Foreign	2,025	1,042	1,126
Total current provision	1,955	2,978	3,043
Deferred provision
Domestic	1,438	1,217	1,297
Foreign	332	152	423
Total deferred provision	1,770	1,369	1,720
Provision for income taxes	$ 3,725	$ 4,347	$ 4,763
Differences in the provision for income taxes from the amount determined by applying the federal statutory rate
Tax provision, computed at statutory rate (as a percent)	34.00%	34.00%	34.00%
State tax, net of federal impact (as a percent)	4.60%	4.80%	0.60%
Change in valuation allowance (as a percent)	0.90%	(3.30%)	(4.70%)
Effect of foreign tax rate differences (as a percent)	(6.50%)	(6.10%)	(4.50%)
Permanent items, other (as a percent)	(0.40%)	0.90%	(0.70%)
R&D Credit (as a percent)	(1.70%)	(1.30%)	(0.50%)
Restricted Stock Awards (as a percent)	(2.70%)	0.00%	0.00%
Other (as a percent)	0.90%	(0.80%)	1.40%
Provision for income taxes (as a percent)	29.10%	28.20%	25.60%
Noncurrent deferred tax assets:
Employee benefit plans	$ 2,247	$ 2,719
Goodwill and Intangibles		215
Other	852	582
Allowances and other	969	977
Net operating loss and tax credit carryforwards	1,003	1,045
Total noncurrent deferred tax assets	5,071	5,538
Valuation allowance	(557)	(439)
Net noncurrent deferred tax assets:	4,514	5,099
Net noncurrent deferred tax liabilities:
Property and Equipment	3,445	2,857
Goodwill and Intangibles	3,136
Other	276	324
Total deferred tax liabilities	6,857	3,181
Net deferred tax asset		$ 1,918
Net deferred tax liabilities	$ (2,343)