Note 6 - Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified			3 Months Ended		32 Months Ended
	Mar. 31, 2014	Jul. 31, 2012 Additional Shares Authorized [Member] Common Class A [Member]	Mar. 31, 2014 Common Class A [Member] Related to Tax Withholdings [Member]	Mar. 31, 2014 Common Class A [Member]	Mar. 31, 2014 Common Class A [Member]	Aug. 31, 2011 Common Class A [Member]
Note 6 - Stockholders' Equity (Details) [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased		1,000,000				2,000,000
Stock Repurchased During Period, Shares				15,000	1,288,047
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share)			$ 65.35	$ 64.46
Stock Repurchased During Period, Value (in Dollars)				$ 1.0
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	1,711,953
Shares Paid for Tax Withholding for Share Based Compensation				106,719
Adjustments Related to Tax Withholding for Share-based Compensation (in Dollars)				$ 7.0