Note M - Stockholders' Equity (Details Textual) - USD ($)					9 Months Ended		12 Months Ended	33 Months Ended	195 Months Ended
	Jan. 04, 2018	Nov. 01, 2017	Mar. 27, 2015	Mar. 10, 2015	Dec. 24, 2017	Dec. 25, 2016	Mar. 31, 2019	Dec. 24, 2017	Dec. 24, 2017	Jun. 05, 2013
Common Stock, Dividends, Per Share, Declared		$ 5		$ 25
Payments of Ordinary Dividends, Common Stock			$ 115,100,000		$ 125,000	$ 375,000		$ 875,000
Dividends Payable			$ 1,000,000		$ 20,948,000			$ 20,948,000	$ 20,948,000
Minimum Percentage of Common Stock Acquired by a Person or Group which Triggers Exercise of New Rights										15.00%
New Right Purchase Price										$ 100
Common Stock, Capital Shares Reserved for Future Issuance					5,696,732			5,696,732	5,696,732	10,188,600
Treasury Stock, Shares, Acquired					0				5,127,373
Treasury Stock, Value, Acquired, Cost Method									$ 77,303,000
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased					260,258			260,258	260,258
Dividends Payable, Date of Record		Dec. 22, 2017		Mar. 20, 2015
Scenario, Forecast [Member]
Payments of Ordinary Dividends, Common Stock							$ 125,000
Dividends on Unvested Restricted Stock [Member]
Dividends Payable		$ 25,000
Subsequent Event [Member]
Payments of Ordinary Dividends, Common Stock	$ 20,923,000