14. QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (Details) - Unaudited Quarterly Results - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
2015
Net sales	$ 65,266,028	$ 70,001,496	$ 68,583,196	$ 65,451,303	$ 78,906,687	$ 72,729,678	$ 68,822,520	$ 65,783,284	$ 269,302,023	$ 286,242,169	$ 244,870,731
Gross margin	22,154,419	22,117,477	22,648,633	21,971,310	27,648,122	24,273,792	22,585,662	21,853,149	88,891,839	96,360,725	83,542,451
Net income	1,382,870	1,803,667	2,002,673	1,413,947	4,471,542	3,138,507	1,511,461	723,788	6,603,157	9,845,298	$ 7,372,756
Dividends paid	$ 832,401	$ 832,073	$ 831,827	$ 755,953	$ 755,012	$ 754,665	$ 754,321	$ 753,981	$ 3,252,254	$ 3,017,979
Net income per common share:
Basic (in Dollars per share)	$ 0.18	$ 0.24	$ 0.26	$ 0.19	$ 0.59	$ 0.42	$ 0.20	$ 0.10	$ 0.87	$ 1.30	$ 0.98
Diluted (in Dollars per share)	$ 0.18	$ 0.24	$ 0.26	$ 0.19	$ 0.59	$ 0.42	$ 0.20	$ 0.10	$ 0.87	$ 1.30	$ 0.98