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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 7,289	$ 1,609	$ 8,676	$ 3,892
Basic (in shares)	6,159	6,381	6,163	6,390
Dilutive effect of common stock equivalents (in shares)	70	49	94	22
Diluted weighted average common shares outstanding (in shares)	6,229	6,430	6,257	6,412
Basic (in dollars per share)	$ 1.18	$ 0.25	$ 1.41	$ 0.61
Diluted (in dollars per share)	$ 1.17	$ 0.25	$ 1.39	$ 0.61