Note N - Stockholders' Equity (Details Textual) - USD ($)								3 Months Ended			9 Months Ended		12 Months Ended	109 Months Ended	207 Months Ended
	Feb. 01, 2019	May 31, 2018	Jan. 04, 2018	Dec. 20, 2017	Nov. 01, 2017	Mar. 27, 2015	Mar. 10, 2015	Dec. 23, 2018	Jun. 24, 2018	Dec. 24, 2017	Dec. 23, 2018	Dec. 24, 2017	Mar. 25, 2018	Dec. 23, 2018	Dec. 23, 2018	Mar. 11, 2016
Common Stock, Dividends, Amount per Annum		$ 1
Common Stock, Dividends, Amount per Quarter		$ 0.25
Common Stock, Dividends, Per Share, Declared								$ 0.25		$ 5	$ 0.75	$ 5
Dividends, Common Stock, Cash											$ 3,139,000
Payments of Ordinary Dividends, Common Stock											3,289,000	$ 125,000
Dividends Payable										$ 20,948,000		$ 20,948,000
Treasury Stock, Shares, Acquired											14,390				5,141,763
Treasury Stock, Value, Acquired, Cost Method											$ 1,000,000				$ 78,303,000
Sixth Stock Repurchase Plan [Member]
Treasury Stock, Shares, Acquired														954,132
Treasury Stock, Value, Acquired, Cost Method														$ 30,641,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased																1,200,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased								245,868			245,868			245,868	245,868
Special Cash Dividend [Member]
Common Stock, Dividends, Per Share, Declared				$ 5	$ 5	$ 25	$ 25
Payments of Ordinary Dividends, Common Stock			$ 20,923,000			$ 115,100,000
Special Cash Dividends on Restricted Stock Declared on November 1, 2017 [Member]
Payments of Ordinary Dividends, Common Stock									$ 25,000
Dividends Payable					$ 25,000
Special Cash Dividends on Restricted Stock Declared on March 10, 2015 [Member]
Payments of Ordinary Dividends, Common Stock									$ 125,000				$ 875,000
Dividends Payable						$ 1,000,000
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.25