Note 6 - Stockholders' Equity (Details) (USD $)	1 Months Ended		9 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2014	Aug. 31, 2014	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2013 Common Class A [Member]	Sep. 30, 2014 Common Class A [Member]	Dec. 11, 2012 Common Class A [Member]
Note 6 - Stockholders' Equity (Details) [Line Items]
Stock Repurchase Program, Authorized Amount							$ 100,000,000
Treasury Stock, Shares, Acquired (in Shares)	186,654	77,700			373,619	264,354
Payments for Repurchase of Common Stock			$ 8,189,000	$ 12,389,000	$ 13,300,000	$ 9,600,000