Note 5 - Share-Based Compensation (Details) - Stock Options Valuation Assumptions	3 Months Ended
	Mar. 31, 2014 Common Class A [Member] Minimum [Member]	Mar. 31, 2014 Common Class B [Member]	Mar. 31, 2013 Maximum [Member]
Note 5 - Share-Based Compensation (Details) - Stock Options Valuation Assumptions [Line Items]
Expected dividend yield at date of grant	0.24%	0.79%	3.46%
Expected stock price volatility	39.29%	33.52%	30.50%
Risk-free interest rate	2.38%	2.38%	1.07%
Expected life of options (in years)	7 years	7 years	6 years