Note P - Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended																12 Months Ended
		Mar. 25, 2018		Dec. 24, 2017		Sep. 24, 2017		Jun. 25, 2017		Mar. 26, 2017		Dec. 25, 2016		Sep. 25, 2016		Jun. 26, 2016		Mar. 25, 2018	Mar. 26, 2017	Mar. 27, 2016
Sales		$ 19,906		$ 22,021		$ 31,471		$ 30,803		$ 19,232		$ 19,873		$ 27,871		$ 29,280		$ 104,201	$ 96,256	$ 100,449
Gross profit (a)	[1]	2,482		4,168		6,486		4,820		2,906		4,074		6,402		5,804
Income from operations		4,546		5,370		8,734		8,450		4,671		4,754		8,031		8,824		27,100	26,280	24,963
Net income (loss)		$ 367		$ (3,779)		$ 3,120		$ 2,922		$ 729		$ 699		$ 2,507		$ 3,550		$ 2,630	$ 7,485	$ 6,096
Net income per share, basic calculation (in dollars per share)		$ 0.09	[2]	$ (0.90)	[2]	$ 0.75	[2]	$ 0.70	[2]	$ 0.17	[2]	$ 0.17	[2]	$ 0.60	[2]	$ 0.85	[2]	$ 0.63	$ 1.79	$ 1.38
Diluted (b) (in dollars per share)		$ 0.09	[2]	$ (0.90)	[2]	$ 0.74	[2]	$ 0.69	[2]	$ 0.17	[2]	$ 0.17	[2]	$ 0.60	[2]	$ 0.85	[2]	$ 0.62	$ 1.78	$ 1.37
Number of shares, basic calculation (in shares)		4,185,000	[2]	4,185,000	[2]	4,179,000	[2]	4,177,000	[2]	4,176,000	[2]	4,175,000	[2]	4,172,000	[2]	4,166,000	[2]	4,181,000	4,172,000	4,430,000
Number of shares, diluted calculation (in shares)		4,228,000	[2]	4,185,000	[2]	4,212,000	[2]	4,215,000	[2]	4,217,000	[2]	4,209,000	[2]	4,207,000	[2]	4,191,000	[2]	4,221,000	4,206,000	4,463,000

[1] Gross profit represents the difference between sales and cost of sales.

[2] The sum of the quarters may not equal the full year per share amounts included in the accompanying consolidated statements of earnings due to the effect of the weighted average number of shares outstanding during the fiscal years as compared to the quarters.