Note 20 - Incentive Plans - Performance Shares Significant Fair Value Assumptions (Details) - Performance Shares [Member] - $ / shares		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock price (in dollars per share)		$ 14.99	$ 24.91	$ 26.29
Dividend yield (1)	[1]	0.00%	0.00%	0.00%
Risk-free rate		2.39%	1.45%	0.87%
Volatility (2)	[2]	22.90%	18.93%	18.80%
Term of the award (Year)		2 years 310 days	2 years 321 days	2 years 321 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.