Consolidated Statements of Changes in Stockholders' Equity - USD ($)	Common Stock [Member] Springfield Bancshares	Common Stock [Member] Bates Companies [Member]	Common Stock [Member] Guaranty Bank and Trust Company [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Springfield Bancshares	Additional Paid-in Capital [Member] Bates Companies [Member]	Additional Paid-in Capital [Member] Guaranty Bank and Trust Company [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Springfield Bancshares	Bates Companies [Member]	Guaranty Bank and Trust Company [Member]	Total
Balance at Dec. 31, 2015				$ 11,761,083				$ 123,282,851	$ 92,965,645	$ (2,123,829)				$ 225,885,750
Net income									27,686,787					27,686,787
Other comprehensive income (loss), net of tax										(335,760)				(335,760)
Common cash dividends declared									(2,035,531)					(2,035,531)
Issuance of shares of common stock, net of issuance costs				1,215,000				28,613,916						29,828,916
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan				20,192				417,336						437,528
Issuance of shares of common stock as a result of stock options exercised				111,423				1,556,823						1,668,246
Stock-based compensation expense								947,174						947,174
Tax benefit of nonqualified stock options exercised								394,149						394,149
Restricted stock awards - shares of common stock				21,882				(21,882)
Exchange of shares of common stock in connection with payroll taxes for restricted stock and in connection with stock options exercised				(22,735)				(546,140)						(568,875)
Adjustment To Additional Paid In Capital Tax Basis Adjustment Related To The Acquisition Of Noncontrolling Interest								2,132,415						2,132,415
Balance at Dec. 31, 2016				13,106,845				156,776,642	118,616,901	(2,459,589)				286,040,799
Net income									35,706,507					35,706,507
Other comprehensive income (loss), net of tax										1,092,153				1,092,153
Common cash dividends declared									(2,664,561)					(2,664,561)
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan				13,318				454,822						468,140
Issuance of shares of common stock as a result of stock options exercised				114,100				1,611,338						1,725,438
Stock-based compensation expense								1,187,036						1,187,036
Restricted stock awards - shares of common stock				28,289				(28,289)
Exchange of shares of common stock in connection with payroll taxes for restricted stock and in connection with stock options exercised				(23,054)				(986,743)						(1,009,797)
Reclassification of certain tax effects from accumulated other comprehensive income									303,814	(303,814)
Issuance of shares of common stock as a result of the acquisition, net of issuance cost			$ 678,670				$ 30,062,744						$ 30,741,414
Balance at Dec. 31, 2017				13,918,168				189,077,550	151,962,661	(1,671,250)				353,287,129
Net income									43,119,699					43,119,699
Other comprehensive income (loss), net of tax										(3,205,499)				(3,205,499)
Impact of adoption of ASU 2016-01									666,900	(666,900)
Common cash dividends declared									(3,545,927)					(3,545,927)
Issuance of shares of common stock as a result of stock purchased under the Employee Stock Purchase Plan				15,528				576,245						591,773
Issuance of shares of common stock as a result of stock options exercised				60,127				733,491						793,618
Stock-based compensation expense								1,443,346						1,443,346
Restricted stock awards - shares of common stock				22,660				(22,660)
Exchange of shares of common stock in connection with payroll taxes for restricted stock and in connection with stock options exercised				(21,190)				(855,475)						(876,665)
Issuance of shares of common stock as a result of the acquisition, net of issuance cost	$ 1,699,414	$ 23,501			$ 78,831,543	$ 976,471					$ 80,530,957	$ 999,972
Balance at Dec. 31, 2018				$ 15,718,208				$ 270,760,511	$ 192,203,333	$ (5,543,649)				$ 473,138,403