Note L - Share-based Compensation (Details Textual) - USD ($)							3 Months Ended		9 Months Ended		12 Months Ended
		Dec. 20, 2017	Nov. 01, 2017	Mar. 29, 2015	Mar. 27, 2015	Mar. 10, 2015	Dec. 24, 2017	Dec. 25, 2016	Dec. 24, 2017	Dec. 25, 2016	Mar. 29, 2015
Allocated Share-based Compensation Expense							$ 99,000	$ 136,000	$ 298,000	$ 482,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized							200,000		$ 200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition									210 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross									0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Replacement Issued	[1]								68,498
Share-based Compensation Arrangements by Share-based Payment Award, Options, Replacement Issued , Weighted Average Exercise Price	[1]								$ 33.438
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	[1]								64,384
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	[1]								$ 35.58
Share Price		$ 83.20			$ 73.56
Common Stock, Dividends, Per Share, Declared			$ 5			$ 25
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price									$ 0
Employee Stock Option [Member]
Allocated Share-based Compensation Expense							$ 38,000	$ 38,000	$ 114,000	$ 114,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross											50,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price											$ 53.89
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period											5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period											4 years
Employee Stock Option [Member] | The 2010 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				75,745
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period				50,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price				$ 53.89
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price				$ 35.58
Special Cash Dividend [Member]
Common Stock, Dividends, Per Share, Declared		5			25
Excluding Dividend [Member]
Share Price		$ 78.20			$ 48.56

[1] Represents the effects on outstanding options after giving effect to the replacement options issued in connection with the Company's special dividend to shareholders of record on December 22, 2017.