Note 20 - Parent Company Only Financial Statements - Condensed Statements of Cash Flows (Details) - USD ($)		3 Months Ended								12 Months Ended
	May 13, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income		$ 8,529,330	$ 6,107,501	$ 6,676,467	$ 6,373,489	$ 6,784,823	$ 6,488,987	$ (523,818)	$ 4,177,889	$ 27,686,787	$ 16,927,881	$ 14,952,537
Stock-based compensation expense										947,174	941,469	891,619
Securities gains, net										(4,592,398)	(798,983)	(92,363)
Gains on debt extinguishment										(1,200,000)	(300,000)
Net increase in interest-bearing deposits at financial institutions										(12,904,803)	(979,283)	(2,289,765)
Calls, maturities and redemptions										117,876,284	211,942,737	35,247,090
Sales										134,188,737	81,410,368	78,476,422
Purchase of premises and equipment										(6,032,416)	(4,394,255)	(2,035,855)
Net cash (used in) provided by investing activities										(168,975,229)	(66,073,152)	(129,927,297)
Proceeds from other borrowings										35,000,000		10,000,000
Calls, maturities and scheduled principal payments											(7,350,000)	(2,125,000)
Prepayments										(69,769,000)	(34,559,000)
Retirement of junior subordinated debentures										(3,955,000)	(1,762,000)
Net proceeds from the common stock offering				$ 29,800,000						2,105,774	1,552,673	620,641
Redemption of 29,867 shares of Series F Noncumulative Perpetual Preferred Stock, net												29,823,922
Net cash provided by financing activities										154,420,080	39,481,832	100,611,611
Net increase (decrease) in cash and due from banks										28,827,672	3,507,302	(3,715,771)
Cash and due from banks, beginning					41,742,321				38,235,019	41,742,321	38,235,019	41,950,790
Cash and due from banks, ending		70,569,993				41,742,321				70,569,993	41,742,321	38,235,019
Common Stock Offering 1 [Member]
Net proceeds from the common stock offering	$ 63,500,000										63,484,123
Common Stock Offering 2 [Member]
Net proceeds from the common stock offering										29,828,916
Parent Company [Member]
Net income										27,686,787	16,927,881	14,952,537
Accretion of acquisition fair value adjustments										136,150	137,317	133,905
Depreciation										222,256	174,757	100,158
Stock-based compensation expense										947,174	941,469	891,619
Securities gains, net										(37,596)	(262,801)
Gains on debt extinguishment										(1,200,000)	(300,000)
Decrease (increase) in other assets										(2,346,253)	(5,929,110)	1,912,597
(Decrease) increase in other liabilities										5,105,251	5,502,390	2,644,458
Net cash provided by operating activities										23,046,243	4,832,689	20,802,089
Net increase in interest-bearing deposits at financial institutions										50	189,426	(2,726)
Purchases										(3,873,060)	(1,764,137)	(40,523)
Calls, maturities and redemptions										3,800,000	1,772,719	71,429
Sales										132,738	489,828
Capital infusion, bank subsidiaries											(45,600,000)
Net cash paid for Community State Bank acquisition										(80,000,000)
Purchase of premises and equipment										(824,498)	(1,517,157)	(16,618)
Net cash (used in) provided by investing activities										(80,764,770)	(46,429,321)	11,562
Proceeds from other borrowings										35,000,000		10,000,000
Calls, maturities and scheduled principal payments											(2,350,000)	(2,359,207)
Prepayments											(19,395,116)
Retirement of junior subordinated debentures										(3,955,000)	(1,762,000)
Payment of cash dividends on common and preferred stock										(1,981,541)	(782,054)	(1,964,608)
Net proceeds from the common stock offering										2,105,774	1,552,673	620,641
Net cash provided by financing activities										60,998,149	40,747,626	(23,527,096)
Net increase (decrease) in cash and due from banks										3,279,622	(849,006)	(2,713,445)
Cash and due from banks, beginning					$ 3,650,133				$ 4,499,139	3,650,133	4,499,139	7,212,584
Cash and due from banks, ending		$ 6,929,755				$ 3,650,133				6,929,755	3,650,133	4,499,139
Parent Company [Member] | Series F Noncumulative Perpetual Preferred Stock [Member]
Redemption of 29,867 shares of Series F Noncumulative Perpetual Preferred Stock, net												(29,823,922)
Parent Company [Member] | Common Stock Offering 1 [Member]
Net proceeds from the common stock offering											63,484,123
Parent Company [Member] | Common Stock Offering 2 [Member]
Net proceeds from the common stock offering										29,828,916
Parent Company [Member] | Bank Subsidiaries [Member]
Earnings of bank subsidiaries										(33,467,712)	(22,059,086)	(20,333,194)
Distributions from bank subsidiaries										26,000,000	9,700,000	20,500,000
Parent Company [Member] | Non-bank Subsidiaries [Member]
Earnings of bank subsidiaries										(32,674)	(32,823)	(32,675)
Distributions from bank subsidiaries										$ 32,860	$ 32,695	$ 32,684