Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Current deferred tax assets
State tax	$ 1,762		$ 1,685
Workers' compensation	1,777		1,586
Health claims	746		651
Vacation liability	1,410		1,211
Allowance for doubtful accounts	205		156
Inventories	6,112		5,685
Sales incentive and advertising allowances	963		757
Stock-based compensation	3,422		3,197
Unrealized foreign exchange gain or loss	247		102
Other, net	(441)		(368)
Current deferred tax assets, net	16,203		14,662
Long-term deferred tax assets (liabilities)
Depreciation	(5,265)		(3,913)
Goodwill and other intangibles amortization	(11,835)		(10,512)
Deferred compensation related to stock options	2,207		3,315
Accrued pension liabilities	0		1,276
Foreign tax credit carryforwards	1,345		0
Uncertain tax positions' unrecognized tax benefits	134		623
Non-United States Tax Loss Carryforwards	7,082		6,506
Tax effect on cumulative translation adjustment	(711)		(789)
Other	588		796
Deferred tax assets, gross, noncurrent	(6,455)		(2,698)
Less valuation allowances	(7,576)		(6,754)
Deferred tax assets, net, noncurrent	(14,031)		(9,452)
Deferred tax assets, net	22,600		22,000
Deferred tax liabilities	20,500		16,800
Operating loss carryforwards
Increase (decrease) in the valuation allowance	(800)	$ (1,300)
Undistributed earnings indefinitely reinvested	51,600	$ 34,800	$ 45,600
Foreign
Operating loss carryforwards
Pre-tax loss carryforwards	31,100
Foreign | Wholly owned Irish subsidiary
Operating loss carryforwards
Pre-tax loss carryforwards	5,900
Foreign | Expiration, 2016
Operating loss carryforwards
Pre-tax loss carryforwards	700
Foreign | Expiration, 2017
Operating loss carryforwards
Pre-tax loss carryforwards	1,600
Foreign | Expiration, 2018
Operating loss carryforwards
Pre-tax loss carryforwards	1,400
Foreign | Expiration, 2019
Operating loss carryforwards
Pre-tax loss carryforwards	2,300
Foreign | Expiration, 2020
Operating loss carryforwards
Pre-tax loss carryforwards	$ 1,700