Note 20 - Parent Company Only Financial Statements (Details) - Condensed Statements of Cash Flows - USD ($)		3 Months Ended								12 Months Ended
	May. 13, 2015	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities:
Net income		$ 6,784,823	$ 6,488,987	$ (523,818)	$ 4,177,889	$ 2,992,821	$ 4,062,665	$ 4,007,836	$ 3,889,215	$ 16,927,881	$ 14,952,537	$ 14,938,245
Distributions in excess of (less than) earnings of:
Bargain purchase gain on Community National acquisition												(1,841,385)
Accretion of acquisition fair value adjustments										(367,009)	(674,539)	(1,060,708)
Stock-based compensation expense										941,469	891,619	792,279
Securities gains, net										(798,983)	(92,363)	(432,492)
Gain on debt extinguishment										(300,000)
Cash Flows from Investing Activities:
Net increase in interest-bearing deposits at financial institutions										(763,749)	(2,289,765)	(8,660,888)
Activity in securities portfolio:
Calls, maturities and redemptions										211,942,737	35,247,090	147,264,900
Sales										81,410,368	78,476,422	37,393,047
Purchase of premises and equipment										(4,394,255)	(2,035,855)	(2,430,353)
Net cash (used in) provided by investing activities										(65,857,618)	(129,927,297)	(164,557,224)
Activity in other borrowings:
Proceeds from other borrowings											10,000,000	10,000,000
Calls, maturities and scheduled principal payments										(7,350,000)	(2,125,000)	(5,800,000)
Prepayments										(34,559,000)
Retirement of junior subordinated debentures										(1,762,000)
Redemption of 29,867 shares of Series F Noncumulative Perpetual Preferred Stock, net											(29,823,922)
Cash and due from banks:
Beginning		41,957,855				38,235,019				41,957,855	38,235,019	41,950,790	$ 61,568,446
Ending		41,957,855				38,235,019				41,957,855	38,235,019	41,950,790	$ 61,568,446
Common Stock Offering 1 [Member]
Activity in other borrowings:
Proceeds from common stock issuance	$ 63,500,000									63,484,123
Common Stock Offering 2 [Member]
Activity in other borrowings:
Proceeds from common stock issuance										1,552,673	620,641	582,742
Net cash provided by (used in) financing activities										39,481,832	100,611,611	112,903,315
Net increase (decrease) in cash and due from banks										3,722,836	(3,715,771)	(19,617,656)
Parent Company [Member]
Cash Flows from Operating Activities:
Net income										16,927,881	14,952,537	14,938,245
Distributions in excess of (less than) earnings of:
Bargain purchase gain on Community National acquisition												(1,841,385)
Accretion of acquisition fair value adjustments										137,317	133,905	79,655
Depreciation										174,757	100,158	75,182
Stock-based compensation expense										941,469	891,619	792,279
Securities gains, net										(262,800)
Gain on debt extinguishment										(300,000)
Decrease (increase) in other assets										(5,929,110)	1,912,597	(725,105)
(Decrease) increase in other liabilities										5,502,390	2,644,458	(2,978,106)
Net cash provided by operating activities										4,832,689	20,802,089	15,841,592
Cash Flows from Investing Activities:
Net increase in interest-bearing deposits at financial institutions										189,426	(2,726)	(2,288)
Activity in securities portfolio:
Purchases										(1,764,137)	(40,523)	(34,040)
Calls, maturities and redemptions										1,772,719	71,429
Sales										489,828
Capital infusion, bank subsidiaries										(45,600,000)
Net cash paid for Community National acquisition												(6,261,684)
Purchase of premises and equipment										(1,517,157)	(16,618)
Net cash (used in) provided by investing activities										(46,429,321)	11,562	(6,298,012)
Activity in other borrowings:
Proceeds from other borrowings											10,000,000	10,000,000
Calls, maturities and scheduled principal payments										(2,350,000)	(2,359,207)	(373,446)
Prepayments										(19,395,116)		(9,550,000)
Retirement of junior subordinated debentures										(1,762,000)
Payment of cash dividends on common and preferred stock										(782,054)	(1,964,608)	(4,062,726)
Net cash provided by (used in) financing activities										40,747,626	(23,527,096)	(3,403,430)
Net increase (decrease) in cash and due from banks										(849,006)	(2,713,445)	6,140,150
Parent Company [Member] | Common Stock Offering 1 [Member]
Activity in other borrowings:
Proceeds from common stock issuance										63,484,123
Parent Company [Member] | Common Stock Offering 2 [Member]
Activity in other borrowings:
Proceeds from common stock issuance										1,552,673	620,641	582,742
Parent Company [Member] | Series F Noncumulative Perpetual Preferred Stock [Member]
Activity in other borrowings:
Redemption of 29,867 shares of Series F Noncumulative Perpetual Preferred Stock, net											(29,823,922)
Beginning of Period [Member] | Parent Company [Member]
Cash and due from banks:
Beginning		4,499,139				7,212,584				4,499,139	7,212,584	1,072,434
Ending		4,499,139				7,212,584				4,499,139	7,212,584	1,072,434
End of Period [Member] | Parent Company [Member]
Cash and due from banks:
Beginning		3,650,133				4,499,139				3,650,133	4,499,139	7,212,584
Ending		$ 3,650,133				$ 4,499,139				3,650,133	4,499,139	7,212,584
Bank Subsidiaries [Member] | Parent Company [Member]
Distributions in excess of (less than) earnings of:
Subsidiaries										(12,359,086)	166,806	5,500,930
Non-bank Subsidiaries [Member] | Parent Company [Member]
Distributions in excess of (less than) earnings of:
Subsidiaries										$ (128)	$ 9	$ (103)