Note 21 - Parent Company Only Financial Statements - Condensed Statements of Income (Details) - USD ($) $ 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
Total interest income	$ 52,977	$ 56,817	$ 54,181	$ 52,101	$ 52,704	$ 49,830	$ 40,799	$ 39,546
Securities gains									$ (30)		$ (88)
Revenue									294,844	$ 224,420	165,999
Total interest expense	13,058	16,098	16,168	15,193	13,109	11,516	8,714	7,143	60,517	40,484	19,452
Salaries and employee benefits									92,063	68,994	55,722
Business acquisition related costs										1,795	1,069
Post-acquisition compensation, transition and integration costs									3,582	2,086	4,310
Disposition costs									3,325
Goodwill impairment									3,000
Income tax benefit	(6,560)	(3,573)	(3,073)	(1,413)	(3,535)	(1,608)	(1,881)	(1,991)	(14,619)	(9,015)	(4,946)
Net income	$ 15,891	$ 15,095	$ 13,504	$ 12,918	$ 13,316	$ 8,809	$ 10,445	$ 10,550	57,408	43,120	35,707
Parent Company [Member] | Reportable Legal Entities [Member]
Total interest income									77	88	13
Securities gains											6
Other									314	(322)	3
Revenue									77,154	54,539	45,201
Total interest expense									5,836	3,637	2,658
Salaries and employee benefits									8,739	6,598	5,022
Professional fees									1,545	1,872	1,345
Business acquisition related costs										1,654	1,069
Post-acquisition compensation, transition and integration costs									3,171	165	3,151
Disposition costs									1,606
Goodwill impairment									3,000
Other									2,147	1,026	1,134
Total expenses									26,044	14,952	14,379
Income before income tax benefit									51,110	39,587	30,822
Income tax benefit									6,298	3,533	4,885
Net income									57,408	43,120	35,707
Parent Company [Member] | Reportable Legal Entities [Member] | Bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									69,966	55,209	45,104
Parent Company [Member] | Reportable Legal Entities [Member] | Non-bank Subsidiaries [Member]
Equity in net income of bank subsidiaries									$ 6,797	$ (436)	$ 75