Note 11 - Share Based Compensation and Employee Benefit Plans - Non-vested Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Non-vested balance (in shares)	1,881,578
Non-vested, weighted average grant date fair value (in dollars per share)	$ 11.28
Granted (in shares)	472,463
Weighted-average fair value of stock options granted (in dollars per share)	$ 12.33	$ 6.54	$ 11.27
Vested (in shares)	(485,279)
Vested, weighted average grant date fair value (in dollars per share)	$ 12.92
Forfeited (in shares)	(32,700)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 11.07
Non-vested balance (in shares)	1,836,062	1,881,578
Non-vested, weighted average grant date fair value (in dollars per share)	$ 11.12	$ 11.28