Note H - Earnings Per Share - Computations of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income	$ 3,446	$ 3,451	$ 7,338	$ 10,378
Basic (in shares)	6,326	6,439	6,368	6,703
Dilutive effect of common stock equivalents (in shares)	47	19	45	22
Diluted (in shares)	6,373	6,458	6,413	6,725
Basic (in dollars per share)	$ 0.54	$ 0.54	$ 1.15	$ 1.55
Diluted (in dollars per share)	$ 0.54	$ 0.53	$ 1.14	$ 1.54