Note P - Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended																12 Months Ended
		Mar. 26, 2017		Dec. 25, 2016		Sep. 25, 2016		Jun. 26, 2016		Mar. 27, 2016		Dec. 27, 2015		Sep. 27, 2015		Jun. 28, 2015		Mar. 26, 2017	Mar. 27, 2016	Mar. 29, 2015
Revenues		$ 19,286		$ 19,937		$ 28,013		$ 29,416		$ 19,053		$ 20,564		$ 30,619		$ 30,654		$ 96,652	$ 100,890	$ 99,112
Gross profit (a)	[1]	2,906		4,074		6,402		5,804		3,254		3,681		6,313		4,785
Income from operations		4,671		4,754		8,031		8,824		4,486		4,435		8,426		7,616		26,280	24,963	19,958
Net income		$ 729		$ 699		$ 2,507		$ 3,550		$ 507		$ 432		$ 2,847		$ 2,310		$ 7,485	$ 6,096	$ 11,703
Net income per share, basic calculation (in dollars per share)		$ 0.17	[2]	$ 0.17	[2]	$ 0.60	[2]	$ 0.85	[2]	$ 0.12	[2]	$ 0.10	[2]	$ 0.64	[2]	$ 0.50	[2]	$ 1.79	$ 1.38	$ 2.61
Net income, diluted calculation (in dollars per share)		$ 0.17	[2]	$ 0.17	[2]	$ 0.60	[2]	$ 0.85	[2]	$ 0.12	[2]	$ 0.10	[2]	$ 0.64	[2]	$ 0.50	[2]	$ 1.78	$ 1.37	$ 2.55
Number of shares, basic calculation (in shares)		4,176,000	[2]	4,175,000	[2]	4,172,000	[2]	4,166,000	[2]	4,297,000	[2]	4,408,000	[2]	4,432,000	[2]	4,584,000	[2]	4,172,000	4,430,000	4,486,000
Number of shares, diluted calculation (in shares)		4,217,000	[2]	4,209,000	[2]	4,207,000	[2]	4,191,000	[2]	4,337,000	[2]	4,444,000	[2]	4,449,000	[2]	4,621,000	[2]	4,206,000	4,463,000	4,588,000

[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.