INCOME TAXES - Tax Effects and Tax Cuts and Jobs Act (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of components of income before income taxes
Domestic	$ 10,894	$ 8,076	$ 4,288
Foreign	9,787	8,060	8,515
Income before income taxes	20,681	16,136	12,803
Current provision
Domestic	1,663	4,750	(70)
Foreign	3,169	2,566	2,025
Total current provision	4,832	7,316	1,955
Deferred provision
Domestic	675	925	1,438
Foreign	(751)	(141)	332
Total deferred provision	(76)	784	1,770
Provision for income taxes	$ 4,756	$ 8,100	$ 3,725
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)	21.00%	35.00%	34.00%
State tax, net of federal impact (as a percent)	3.00%	3.60%	4.60%
Change in valuation allowance (as a percent)	2.80%	1.90%	0.90%
Effect of foreign tax rate differences (as a percent)	3.40%	(4.20%)	(6.50%)
Permanent items, other (as a percent)	0.80%	0.20%	(0.40%)
R&D Credit (as a percent)	(0.80%)	(2.20%)	(1.70%)
Restricted Stock Awards (as a percent)	(2.30%)	(2.60%)	(2.70%)
Effect of Tax Cuts and Jobs Act (as a percent)	(5.10%)	19.40%	0.00%
Other (as a percent)	0.20%	(0.90%)	0.90%
Provision for income taxes (as a percent)	23.00%	50.20%	29.10%
Effective tax rate excluding adjustments related to Tax Cuts and Jobs Act, Tax rate
Recognized provisional amount included as a component of income tax expense from continuing operations		$ 3,133
Provision for income taxes	$ 2,898
Reduction to provision for income taxes	$ 235
Decreased in effective tax rate (as a percent)	1.10
Transition tax liability		3,140
Decrease in transition tax liability		$ 17
Transition tax liability period (in years)		8 years
Remaining transition tax obligation	$ 1,855
Provisional amount of deferred tax balance		$ (7)
Decrease in deferred tax balance		218
Noncurrent deferred tax assets:
Employee benefit plans	1,983	1,896
Net operating loss and tax credit carryforwards	983	640
Allowances and other	1,507	203
Other	326	370
Total noncurrent deferred tax assets	4,799	3,109
Valuation allowance	(1,003)	(50)
Net noncurrent deferred tax assets:	3,796	3,059
Net noncurrent deferred tax liabilities:
Property and Equipment	3,708	3,001
Goodwill and Intangibles	3,188	3,398
Other	419	255
Total deferred tax liabilities	7,315	6,654
Net deferred tax asset/(deferred tax liability)	(3,519)	(3,595)
Foreign tax credits		900
Tax effect on net operating losses		$ 100
Unremitted earnings	$ 200