Note 21 - Stock Based Compensation - Stock Option Award Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding, beginning of year (in shares)	5,642,623	6,644,274	7,252,380
Outstanding, weighted average exercise price, beginning of year (in dollars per share)	$ 25.22	$ 26.14	$ 28.17
Granted (in shares)	450,000	0	45,360
Granted, weighted-average exercise price (in dollars per share)	$ 30.73		$ 20.07
Exercised (in shares)	(364,418)	(380,786)	0
Exercised, weighted-average exercise price (in dollars per share)	$ 27.06	$ 24.84
Forfeited (in shares)	(9,213)		(11,340)
Forfeited, weighted-average exercise price (in dollars per share)	$ 22.10		$ 26.28
Cancelled (in shares)	(187,110)	(620,865)	(642,126)
Cancelled, weighted-average exercise price (in dollars per share)	$ 30.18	$ 35.24	$ 48.61
Outstanding, end of year (in shares)	5,531,882	5,642,623	6,644,274
Outstanding, end of year (in dollars per share)	$ 25.38	$ 25.22	$ 26.14