CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net sales	$ 118,251	$ 113,668
Cost of sales	97,118	90,305
Gross profit	21,133	23,363
Selling, general and administrative expense	20,692	20,975
Restructuring charges	4	33
Income from operations	437	2,355
Interest expense	(1,177)	(1,424)
Other income/expense, net	(238)	(208)
(Loss) earnings before provision for (benefit from) income taxes	(978)	723
Provision for (benefit from) income taxes	325	(23)
Net (loss) earnings available to common stockholders	(1,303)	746
Class A Common Share [Member]
Net (loss) earnings available to common stockholders	$ (240)	$ 116
Net (loss) earnings per common share:
Common share - basic and diluted (in dollars per share)	$ (0.11)	$ 0.05
Weighted-average number of shares outstanding:
Common share - basic and diluted (in shares)	2,175	2,175
Dividends paid per common share:
Common share (in dollars per share)	$ 0.06	$ 0.06
Class B Common Share [Member]
Net (loss) earnings available to common stockholders	$ (1,063)	$ 630
Net (loss) earnings per common share:
Common share - basic and diluted (in dollars per share)	$ (0.11)	$ 0.06
Weighted-average number of shares outstanding:
Common share - basic and diluted (in shares)	9,856	9,845
Dividends paid per common share:
Common share (in dollars per share)	$ 0.07	$ 0.07