Note 17 - Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 72,373	$ 6,622	$ 3,687	$ 5,499	$ 1,836	$ 9,445	$ 6,051	$ 35,826	$ 88,181	$ 53,158	$ 23,511
Less: distributed earnings allocated to non-vested stock											(6)
Less: undistributed earnings allocated to non-vested restricted stock										(16)	(21)
Numerator for basic earnings per share									88,181	53,142	23,484
Add: undistributed earnings allocated to non-vested restricted stock										16	21
Less: undistributed earnings reallocated to non-vested restricted stock										(16)	(21)
Numerator for diluted earnings per share									$ 88,181	$ 53,142	$ 23,484
Weighted average shares outstanding – basic (in shares)									43,743,243	43,725,333	43,676,171
Stock options and other awards (in shares)									1,433	5,859	9,408
Weighted average shares outstanding – diluted (in shares)									43,744,676	43,731,192	43,685,579
Basic earnings per share (in dollars per share)	$ 1.65	$ 0.15	$ 0.08	$ 0.13	$ 0.04	$ 0.22	$ 0.14	$ 0.82	$ 2.02	$ 1.22	$ 0.54
Diluted earnings per share (in dollars per share)	$ 1.65	$ 0.15	$ 0.08	$ 0.13	$ 0.04	$ 0.22	$ 0.14	$ 0.82	$ 2.02	$ 1.22	$ 0.54