Note 20 - Incentive Plans - Performance Shares Significant Fair Value Assumptions (Details) - Performance Shares [Member] - $ / shares		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock price (in dollars per share)		$ 17.81	$ 14.99	$ 24.91
Dividend yield (1)	[1]	0.00%	0.00%	0.00%
Risk-free rate		2.52%	2.39%	1.45%
Volatility (2)	[2]	24.55%	22.90%	18.93%
Term of the award (Year)		2 years 10 months 17 days	2 years 10 months 6 days	2 years 10 months 17 days

[1] Total Shareholder Returns, as used in the performance share awards computation, are measured based on cumulative dividend stock prices, as such a zero percent dividend yield is utilized.

[2] Volatility is based on the annualized standard deviation of the daily logarithmic returns on dividend-adjusted closing prices over the look-back period based on the term of the award.