Note 11 - Share Based Compensation and Employee Benefit Plans - Non-vested Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Non-vested balance (in shares)	1,836,062
Non-vested, weighted average grant date fair value (in dollars per share)	$ 11.12
Granted (in shares)	459,663
Weighted-average fair value of stock options granted (in dollars per share)	$ 15.46	$ 12.33	$ 6.54
Vested (in shares)	(430,040)
Vested, weighted average grant date fair value (in dollars per share)	$ 13.26
Forfeited (in shares)	(69,329)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 10.73
Non-vested balance (in shares)	1,796,356	1,836,062
Non-vested, weighted average grant date fair value (in dollars per share)	$ 11.74	$ 11.12