Note 18 - Share-based Compensation - Valuation Assumptions (Details) - Share-based Payment Arrangement, Option [Member]	12 Months Ended	36 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020
Expected volatility			25.00%
Weighted-average expected volatility	27.00%	26.00%	25.00%
Expected dividend yield	1.30%		1.20%
Expected term, in years (Year)	5 years	5 years	5 years
Minimum [Member]
Expected volatility	27.00%	26.00%
Expected dividend yield		1.20%
Risk-free interest rate	0.30%	1.60%	2.60%
Maximum [Member]
Expected volatility	32.00%	27.00%
Expected dividend yield		1.40%
Risk-free interest rate	1.30%	2.50%	2.90%
Weighted Average [Member]
Expected dividend yield	1.30%	1.20%	1.20%

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Rate of weighted-average expected volatility for award under share-based payment arrangement.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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