CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
NET SALES	$ 848,456	$ 717,476	$ 651,286
COSTS OF OPERATIONS	766,037	647,624	572,928
GROSS PROFIT	82,419	69,852	78,358
OPERATING EXPENSES:
Selling, general and administrative expenses	52,827	46,233	39,714
NON-OPERATING (INCOME) EXPENSES:
Interest expense, net	3,379	1,355	1,215
Other (income) expense, net	481	498	(668)
Total expense, net	56,687	48,086	40,261
INCOME BEFORE INCOME TAXES	25,732	21,766	38,097
INCOME TAX PROVISION	5,386	5,511	8,267
NET INCOME	$ 20,346	$ 16,255	$ 29,830
BASIC INCOME PER COMMON SHARE (in dollars per share)	$ 1.78	$ 1.42	$ 2.62
DILUTED INCOME PER COMMON SHARE (in dollars per share)	1.78	1.42	2.62	$ 3.43
CASH DIVIDENDS DECLARED PER COMMON SHARE (in dollars per share)	$ 0.72	$ 0.72	$ 0.72
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)	11,417	11,411	11,405
Diluted (in shares)	11,417	11,411	11,405	11,400