Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2014	$ 8,074,443	$ 61,668,968	$ 77,876,824	$ (1,935,216)	$ (1,606,510)	$ 144,078,509
Net income			4,177,889			4,177,889
Other comprehensive income, net of tax				2,220,865		2,220,865
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	5,679	82,641				88,320
Proceeds from issuance of shares of common stock as a result of stock options exercised	9,688	94,728				104,416
Stock compensation expense		367,775				367,775
Tax benefit of nonqualified stock options exercised		15,651				15,651
Restricted stock awards	26,502	(26,502)
Exchange of shares of common stock in connection with restricted stock vested, net	(3,272)	(54,188)				(57,460)
Balance at Mar. 31, 2015	8,113,040	62,149,073	82,054,713	285,649	(1,606,510)	150,995,965
Balance at Dec. 31, 2014	8,074,443	61,668,968	77,876,824	(1,935,216)	(1,606,510)	144,078,509
Net income						10,143,058
Other comprehensive income, net of tax						2,098,427
Balance at Sep. 30, 2015	11,728,911	122,573,712	86,649,405	163,211		221,115,239
Tax basis adjustment related to the acquisition of noncontrolling interest in m2 Lease Funds
Balance at Mar. 31, 2015	8,113,040	62,149,073	82,054,713	285,649	(1,606,510)	150,995,965
Net income			(523,818)			(523,818)
Other comprehensive income, net of tax				(2,378,921)		(2,378,921)
Common cash dividends declared			(464,706)			(464,706)
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	8,558	128,927				137,485
Proceeds from issuance of shares of common stock as a result of stock options exercised	17,240	238,717				255,957
Stock compensation expense		186,751				186,751
Tax benefit of nonqualified stock options exercised		15,827				15,827
Restricted stock awards	1,616	(1,616)
Exchange of shares of common stock in connection with stock options exercised	(630)	(10,616)				(11,246)
Balance at Jun. 30, 2015	11,819,824	122,511,186	81,066,189	(2,093,272)	(1,606,510)	211,697,417
Proceeds from issuance of shares of common stock, net of issuance costs	3,680,000	59,804,123				63,484,123
Net income			6,488,987			6,488,987
Other comprehensive income, net of tax				2,256,483		2,256,483
Common cash dividends declared			(1,393)			(1,393)
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	5,394	81,309				86,703
Proceeds from issuance of shares of common stock as a result of stock options exercised	24,711	318,732				343,443
Stock compensation expense		203,967				203,967
Tax benefit of nonqualified stock options exercised		39,632				39,632
Restricted stock awards	228	(228)
Balance at Sep. 30, 2015	11,728,911	122,573,712	86,649,405	163,211		221,115,239
Retirement of treasury stock, shares of common stock	(121,246)	(580,886)	(904,378)		$ 1,606,510
Balance at Dec. 31, 2015	11,761,083	123,282,851	92,965,645	(2,123,829)		225,885,750
Net income			6,373,489			6,373,489
Other comprehensive income, net of tax				2,525,411		2,525,411
Common cash dividends declared			(470,873)			(470,873)
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	5,054	94,560				99,614
Proceeds from issuance of shares of common stock as a result of stock options exercised	46,020	729,473				775,493
Stock compensation expense		382,761				382,761
Tax benefit of nonqualified stock options exercised		22,508				22,508
Restricted stock awards	22,382	(22,382)
Exchange of shares of common stock in connection with stock options exercised	(15,689)	(346,834)				(362,523)
Exchange of shares of common stock in connection with restricted stock vested, net	(3,939)	(84,972)				(88,911)
Balance at Mar. 31, 2016	11,814,911	124,057,965	98,868,261	401,582		235,142,719
Balance at Dec. 31, 2015	11,761,083	123,282,851	92,965,645	(2,123,829)		225,885,750
Net income						19,157,457
Other comprehensive income, net of tax						3,344,860
Balance at Sep. 30, 2016	13,075,307	155,950,678	110,610,144	1,221,031		280,857,160
Tax basis adjustment related to the acquisition of noncontrolling interest in m2 Lease Funds						2,132,415
Balance at Mar. 31, 2016	11,814,911	124,057,965	98,868,261	401,582		235,142,719
Net income			6,676,467			6,676,467
Other comprehensive income, net of tax				1,180,633		1,180,633
Common cash dividends declared			(520,701)			(520,701)
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	6,982	142,887				149,869
Proceeds from issuance of shares of common stock as a result of stock options exercised	20,975	230,671				251,646
Stock compensation expense		187,569				187,569
Tax benefit of nonqualified stock options exercised		87,858				87,858
Restricted stock awards	(500)	500
Balance at Jun. 30, 2016	13,057,368	155,453,781	105,024,027	1,582,215		275,117,391
Proceeds from issuance of shares of common stock, net of issuance costs	1,215,000	28,613,916				29,828,916
Tax basis adjustment related to the acquisition of noncontrolling interest in m2 Lease Funds		2,132,415				2,132,415
Net income			6,107,501			6,107,501
Other comprehensive income, net of tax				(361,184)		(361,184)
Common cash dividends declared			(521,384)			(521,384)
Proceeds from issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan	4,085	85,217				89,302
Proceeds from issuance of shares of common stock as a result of stock options exercised	14,692	173,890				188,582
Stock compensation expense		190,211				190,211
Tax benefit of nonqualified stock options exercised		72,694				72,694
Exchange of shares of common stock in connection with stock options exercised	(838)	(25,115)				(25,953)
Balance at Sep. 30, 2016	$ 13,075,307	$ 155,950,678	$ 110,610,144	$ 1,221,031		$ 280,857,160