Note 7 - Share-Based Compensation (Details) - Stock Options Valuation Assumptions	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Minimum [Member]
Note 7 - Share-Based Compensation (Details) - Stock Options Valuation Assumptions [Line Items]
Expected dividend yield at date of grant	2.26%	2.63%	2.00%
Expected stock price volatility	30.34%	29.10%	28.70%
Risk-free interest rate	0.55%	0.56%	1.70%
Expected life of options (in years)	4 years	4 years	4 years
Maximum [Member]
Note 7 - Share-Based Compensation (Details) - Stock Options Valuation Assumptions [Line Items]
Expected dividend yield at date of grant	3.46%	3.98%	2.55%
Expected stock price volatility	30.51%	31.70%	32.00%
Risk-free interest rate	1.07%	1.15%	2.14%
Expected life of options (in years)	6 years	6 years	6 years