Note 18 - Share-based Compensation - Valuation of Option Grants Under Stock Plans (Details)	12 Months Ended
	Dec. 31, 2020
Expected volatility and Weighted-average volatility	32.90%
Expected dividends	4.48%
Risk-free rate and Average risk-free rate	0.50%
Expected term (in years) (Year)	7 years 4 months 24 days
Pre-vesting executive departure rate	0.60%
Pre-vesting non-executive departure rate	2.50%