Quarterly Data - Quarterly Data (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 26,377,000	$ 31,913,000	$ 40,997,000	$ 25,288,000	$ 23,118,000	$ 29,903,000	$ 33,954,000	$ 22,837,000	$ 124,574,371	$ 109,811,768
Cost of goods sold	16,564,000	20,050,000	26,302,000	16,103,000	14,852,000	19,578,000	21,419,000	14,402,000	79,019,315	70,250,550
Net income	$ 545,000	$ 1,473,000	$ 3,267,000	$ 565,000	$ 440,000	$ 1,208,000	$ 2,710,000	$ 436,000	$ 5,850,998	$ 4,793,525
Basic earnings per share	$ .16	$ .44	$ .98	$ .17	$ .12	$ .36	$ .82	$ .13	$ 1.76	$ 1.44
Diluted earnings per share	.15	.40	.91	.16	.11	.33	.74	.12	1.64	1.30
Dividends per share	$ .10	$ .10	$ .10	$ .10	$ .1	$ .09	$ .09	$ .09	$ .40	$ .37