Note D - Income Per Share - Earnings Per Share Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2017	Sep. 25, 2016	Sep. 24, 2017	Sep. 25, 2016
Net income, basic calculation	$ 3,120	$ 2,507	$ 6,042	$ 6,057
Number of shares, basic calculation (in shares)	4,179,000	4,172,000	4,178,000	4,169,000
Net income per share, basic calculation (in dollars per share)	$ 0.75	$ 0.60	$ 1.45	$ 1.45
Effect of dilutive employee stock options (in shares)	33,000	35,000	35,000	30,000
Effect of dilutive employee stock option (in dollars per share)	$ (0.01)		$ (0.02)	$ (0.01)
Net income, diluted calculation	$ 3,120	$ 2,507	$ 6,042	$ 6,057
Number of shares, diluted calculation (in shares)	4,212,000	4,207,000	4,213,000	4,199,000
Net income per share, diluted calculation (in dollars per share)	$ 0.74	$ 0.60	$ 1.43	$ 1.44