CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited)
Revenues	$ 39,169,000	$ 43,594,000
Cost of goods sold	22,830,000	23,726,000
Gross profit	16,339,000	19,868,000
Operating expenses:
Selling	1,926,000	2,070,000
General and administrative	4,172,000	4,400,000
Research and development	1,310,000	1,684,000
Operating expenses	7,408,000	8,154,000
Operating income	8,931,000	11,714,000
Interest and dividend income	217,000	462,000
Other investment income/(losses)	62,000	(997,000)
Other income	66,000	0
Non operating income	345,000	(535,000)
Income before provision for income taxes	9,276,000	11,179,000
Provision for income taxes	(1,550,000)	(2,281,000)
Net income	$ 7,726,000	$ 8,898,000
Net income per basic share	$ 4.23	$ 4.80
Weighted average basic shares outstanding	1,826	1,853
Net income per diluted share	$ 4.22	$ 4.79
Weighted average diluted shares outstanding	1,832	1,859
Dividends per common share	$ 1.75	$ 1.55