CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
NET SALES	$ 147,597	$ 126,205	$ 452,525	$ 404,530
COSTS OF OPERATIONS	130,481	113,409	403,402	362,241
GROSS PROFIT	17,116	12,796	49,123	42,289
OPERATING EXPENSES:
Selling, general and administrative expenses	8,495	7,524	24,823	22,612
Interest expense, net	359	291	816	699
Other (income) expense, net	(238)	(94)	(451)	227
Total operating expenses	8,616	7,721	25,188	23,538
INCOME BEFORE INCOME TAXES	8,500	5,075	23,935	18,751
INCOME TAX PROVISION	2,978	1,907	8,466	6,653
NET INCOME	$ 5,522	$ 3,168	$ 15,469	$ 12,098
BASIC INCOME PER COMMON SHARE	$ 0.49	$ 0.28	$ 1.36	$ 1.07
DILUTED INCOME PER COMMON SHARE	0.49	0.28	1.36	1.07
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 0.17	$ 0.16	$ 0.51	$ 0.48
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)	11,346	11,341	11,346	11,329
Diluted (in shares)	11,374	11,368	11,374	11,367