Note 21 - Parent Company Only Financial Statements - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Feb. 12, 2019	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		$ 15,891	$ 15,095	$ 13,504	$ 12,918	$ 13,316	$ 8,809	$ 10,445	$ 10,550	$ 57,408	$ 43,120	$ 35,707
Accretion of acquisition fair value adjustments, net										(4,344)	(5,527)	(4,941)
Depreciation										5,225	4,451	3,949
Stock-based compensation expense										2,469	1,443	1,187
Securities gains, net										30		88
Goodwill impairment										3,000
Gains on debt extinguishment				$ 50						436
Net decrease (increase) in interest-bearing deposits at financial institutions										(69,984)	(14,508)	12,138
Purchases										(71,963)	(84,045)	(179,786)
Calls, maturities and redemptions										25,193	23,931	43,010
Sales										30,055	1,938	71,092
Net cash paid for acquisition											(5,183)	(3,369)
Purchase of premises and equipment										(12,429)	(11,457)	(5,761)
Net cash (used in) investing activities										(308,664)	(333,648)	(410,517)
Proceeds from other borrowings											9,000	7,000
Paydown of revolving line of credit										9,000
Prepayments										(46,313)
Calls, maturities and scheduled principal payments										(11,937)	(12,550)	(21,000)
Proceeds from subordinated notes	$ 63,400									63,393
Proceeds from issuance of common stock, net										1,926	1,279	2,056
Net cash provided by (used in) financing activities										222,901	279,178	381,956
Net increase (decrease) in cash and due from banks										(9,269)	9,801	5,152
Parent Company [Member] | Reportable Legal Entities [Member]
Net income										57,408	43,120	35,707
Accretion of acquisition fair value adjustments, net										305	183	149
Depreciation										327	249	225
Stock-based compensation expense										2,469	1,443	1,187
Securities gains, net												(6)
Goodwill impairment										3,000
Decrease (increase) in other assets										26	2,232	(969)
(Decrease) increase in other liabilities										7,814	(7,226)	(6,919)
Net cash provided by operating activities										39,644	19,791	5,234
Net decrease (increase) in interest-bearing deposits at financial institutions										(4,600)	(1,000)
Calls, maturities and redemptions												(6)
Sales												32
Net cash paid for acquisition											(5,183)	(3,369)
Purchase of premises and equipment										(2,861)	(2,257)	(69)
Net cash (used in) investing activities										16,161	11,940	3,400
Proceeds from other borrowings											9,000	7,000
Paydown of revolving line of credit										(9,000)
Prepayments										(21,313)
Calls, maturities and scheduled principal payments										(1,799)	(12,550)	(11,000)
Proceeds from subordinated notes										63,393
Payment of cash dividends on common and preferred stock										(3,767)	(3,300)	(2,494)
Net cash provided by (used in) financing activities										29,440	(5,571)	(4,438)
Net increase (decrease) in cash and due from banks										52,923	2,280	(2,604)
Cash and due from banks, beginning					$ 6,606				$ 4,326	6,606	4,326	6,930
Cash and due from banks, ending		$ 59,529				$ 6,606				59,529	6,606	4,326
Parent Company [Member] | Reportable Legal Entities [Member] | Common Stock Offering 2 [Member]
Proceeds from issuance of common stock, net										1,926	1,279	2,056
Parent Company [Member] | Reportable Legal Entities [Member] | Bank Subsidiaries [Member]
Earnings of bank subsidiaries										(69,966)	(55,209)	(45,104)
Distributions from bank subsidiaries											34,500	21,000
Parent Company [Member] | Reportable Legal Entities [Member] | Non-bank Subsidiaries [Member]
Earnings of bank subsidiaries										(6,797)	436	(75)
Distributions from bank subsidiaries										45,058	63	$ 39
Parent Company [Member] | Reportable Legal Entities [Member] | Bank Subsidiaries [Member]
Capital infusion to subsidiaries										(8,600)	$ (3,500)
Parent Company [Member] | Reportable Legal Entities [Member] | Non-bank Subsidiaries [Member]
Capital infusion to subsidiaries										$ (100)