Note 8 - Marketable Securities and Other Investments (Details) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended			1 Months Ended	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Apr. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Note 8 - Marketable Securities and Other Investments (Details) [Line Items]
Marketable Securities	$ 105,253,000	[1]				$ 90,235,000	[1]
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	61,900,000
Proceeds from Sale and Maturity of Marketable Securities	700,000		219,000
Subsequent Event [Member] | Supervalu Inc. [Member]
Note 8 - Marketable Securities and Other Investments (Details) [Line Items]
Marketable Securities, Number of Shares Sold (in Shares)				6.4
Proceeds from Sale and Maturity of Marketable Securities				58,600,000
Marketable Securities, Realized Gain (Loss)					$ 32,400,000

[1] As of March 31, 2015 and December 31, 2014, the Company determined that $102.7 million and $87.7 million, respectively, of the Marketable securities estimated fair value were classified within Level 1 of the fair value hierarchy and the remaining $2.4 million and $2.3 million, respectively, were classified within Level 3 of the fair value hierarchy.