Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
State tax	$ 919	$ 1,390
Workers’ compensation	785	822
Health claims	445	487
Vacation liability	370	1,008
Allowance for doubtful accounts	171	104
Inventories	5,659	5,385
Sales incentive and advertising allowances	799	709
Stock-based compensation	3,074	2,967
Unrealized foreign exchange gain or loss	440	291
Foreign tax credit carryforwards	5,043	4,453
Uncertain tax positions’ unrecognized tax benefits	39	31
Foreign tax loss carry forward	8,091	6,892
Other	1,813	1,291
Deferred tax assets, gross	27,648	25,830
Less valuation allowances	13,254	11,114
Deferred tax assets, net, noncurrent	14,394	14,716
Deferred tax liabilities
Depreciation	(9,189)	(7,050)
Goodwill and other intangibles amortization	(13,027)	(11,331)
Tax effect on cumulative translation adjustment	(497)	(487)
Deferred tax liabilities	(22,713)	(18,868)
Total Deferred tax asset/(liability)	(8,319)	(4,152)
Operating loss carryforwards
Deferred tax assets, net, noncurrent	14,394	$ 14,716
Pre-tax loss carryforwards	$ 37,000