Note 6 - Preferred Stock (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Jan. 26, 2013	Apr. 28, 2012
Proceeds from Issuance of Preferred Stock and Preference Stock (in Dollars)	$ 19,710
Series D Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues (in Shares)	400,000
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Stock Issued During Period, Value, New Issues (in Dollars)	20,000
Preferred Stock, Liquidation Preference Per Share	$ 50
Preferred Stock, Dividend Rate, Percentage	3.00%
Preferred Stock Dividend Rate, Basis Spread on Variable Rate	370
Preferred Stock, Redemption Price Per Share	$ 50
Proceeds from Issuance of Preferred Stock and Preference Stock (in Dollars)	$ 19,700
Series C Preferred Stock [Member]
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Treasury Stock, Shares (in Shares)	150,000	150,000