CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) [Abstract]
Net sales	$ 60,692,645	$ 57,357,442	$ 183,015,723	$ 177,663,291
Cost of products sold	(45,754,911)	(43,139,780)	(139,243,164)	(133,670,797)
Gross margin	14,937,734	14,217,662	43,772,559	43,992,494
Product development expenses	(825,425)	(2,004,919)	(5,240,004)	(5,089,178)
Selling and administrative expenses	(8,391,898)	(7,472,335)	(24,866,665)	(25,602,515)
Restructuring costs	0	0	(2,651,877)	0
Operating profit	5,720,411	4,740,408	11,014,013	13,300,801
Interest expense	(420,377)	(310,507)	(974,536)	(918,897)
Other income	188,623	228,787	789,371	673,287
Income before income taxes	5,488,657	4,658,688	10,828,848	13,055,191
Income taxes	1,295,575	892,027	2,535,033	2,929,858
Net income	$ 4,193,082	$ 3,766,661	$ 8,293,815	$ 10,125,333
Earnings per Share:
Basic (in dollars per share)	$ 0.67	$ 0.60	$ 1.33	$ 1.62
Diluted (in dollars per share)	0.67	0.60	1.33	1.61
Cash dividends per share: (in dollars per share)	$ 0.11	$ 0.11	$ 0.33	$ 0.33