Note 5 - Capital Stock and Transactions with Related Parties (Details) (USD $)	1 Months Ended	0 Months Ended	1 Months Ended	12 Months Ended		12 Months Ended			1 Months Ended	15 Months Ended
	Dec. 27, 2012	Feb. 14, 2011	Jan. 22, 2010	Apr. 27, 2013	Mar. 31, 2012	Apr. 27, 2013 CMA [Member]	Apr. 28, 2012 CMA [Member]	Apr. 30, 2011 CMA [Member]	Jan. 25, 2013 Series D Preferred Stock [Member]	Apr. 30, 2014 Series D Preferred Stock [Member]	May 01, 2014 Series D Preferred Stock [Member]	Apr. 27, 2013 Series D Preferred Stock [Member]	Apr. 28, 2012 Series D Preferred Stock [Member]	Apr. 27, 2013 Series C Preferred Stock [Member]	Apr. 28, 2012 Series C Preferred Stock [Member]
Note 5 - Capital Stock and Transactions with Related Parties (Details) [Line Items]
Dividends, Common Stock, Cash	$ 118,100,000	$ 106,300,000	$ 62,300,000
Common Stock, Dividends, Per Share, Cash Paid (in Dollars per share)	$ 2.55	$ 2.30	$ 1.35
Stock Issued During Period, Shares, New Issues (in Shares)									400,000
Preferred Stock, Par or Stated Value Per Share (in Dollars per share)									$ 1			$ 1	$ 1	$ 1	$ 1
Stock Issued During Period, Value, New Issues									20,000,000
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)									$ 50
Preferred Stock, Dividend Rate, Percentage										3.00%
Preferred Stock Dividend Rate, Basis Spread on Variable Rate											370
Dividends Payable, Current												141,000
Preferred Stock, Redemption Price Per Share (in Dollars per share)											$ 50
Proceeds from Issuance of Preferred Stock and Preference Stock				19,704,000					19,700,000
Treasury Stock, Shares (in Shares)														150,000	150,000
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in Shares)				1,600,000	800,000
Stock Repurchased During Period, Shares (in Shares)				502,060
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in Shares)				1,097,940
Related Party Transaction, Amounts of Transaction						6,600,000	6,300,000	6,000,000
Accounts Payable						$ 3,100,000	$ 3,000,000