Note 20 - Parent Company Financial Statements - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents	$ 120,408	$ 113,534	$ 120,493	$ 100,914
Other assets	33,133	38,026
Total assets	1,673,872	1,671,030
Dividends payable, common stock	939	751
Subordinated notes payable	33,506	33,506
Other liabilities	28,440	27,784
Total liabilities	1,480,519	1,486,964
Common stock	940	939
Capital surplus	52,201	51,885
Retained earnings	143,778	134,650
Accumulated other comprehensive loss	(3,566)	(3,408)
Total liabilities and shareholders’ equity	1,673,872	1,671,030
Parent Company [Member]
Cash and cash equivalents	61,604	44,286	$ 35,964	$ 32,086
Investment in subsidiaries	166,183	175,935
Other assets	302	1,378
Total assets	228,089	221,599
Dividends payable, common stock	939	751
Subordinated notes payable	33,506	33,506
Other liabilities	291	3,276
Total liabilities	34,736	37,533
Common stock	940	939
Capital surplus	52,201	51,885
Retained earnings	143,778	134,650
Accumulated other comprehensive loss	(3,566)	(3,408)
Total shareholders’ equity	193,353	184,066
Total liabilities and shareholders’ equity	$ 228,089	$ 221,599