Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Sales	$ 338,286	$ 356,858	$ 317,697
Cost of sales	258,364	271,650	245,035
Gross profit	79,922	85,208	72,662
Operating expenses:
Salaries and commissions	37,180	38,110	36,570
Other operating expenses	33,238	30,962	28,716
Depreciation and amortization	2,502	2,178	2,772
Impairment charge	120	60
Total operating expenses	73,040	71,310	68,058
Operating income	6,882	13,898	4,604
Interest expense	3,057	2,907	2,073
Income before income taxes	3,825	10,991	2,531
Income tax expense	1,275	2,355	2,753
Net income (loss)	$ 2,550	$ 8,636	$ (222)
Earnings (loss) per share:
Basic (in dollars per share)	$ 0.16	$ 0.53	$ (0.01)
Diluted (in dollars per share)	$ 0.15	$ 0.52	$ (0.01)
Weighted average common shares outstanding:
Basic (in shares)	16,433,644	16,389,876	16,269,611
Diluted (in shares)	16,552,866	16,523,599	16,269,611