CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Common Stock [Member]	Common Stock [Member] Bankers Healthcare Group, LLC [Member]	Common Stock [Member] Avenue Financial Holdings, Inc. (Avenue) [Member]	Common Stock [Member] CapitalMark Bank & Trust [Member]	Common Stock [Member] Magna Bank [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Bankers Healthcare Group, LLC [Member]	Additional Paid-in Capital [Member] Avenue Financial Holdings, Inc. (Avenue) [Member]	Additional Paid-in Capital [Member] CapitalMark Bank & Trust [Member]	Additional Paid-in Capital [Member] Magna Bank [Member]	Retained Earnings [Member]	Retained Earnings [Member] Bankers Healthcare Group, LLC [Member]	Retained Earnings [Member] Avenue Financial Holdings, Inc. (Avenue) [Member]	Retained Earnings [Member] CapitalMark Bank & Trust [Member]	Retained Earnings [Member] Magna Bank [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Bankers Healthcare Group, LLC [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Avenue Financial Holdings, Inc. (Avenue) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] CapitalMark Bank & Trust [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Magna Bank [Member]	Total	Bankers Healthcare Group, LLC [Member]	Avenue Financial Holdings, Inc. (Avenue) [Member]	CapitalMark Bank & Trust [Member]	Magna Bank [Member]
Balance at Dec. 31, 2013	$ 35,221,941					$ 550,212,135					$ 142,298,199					$ (4,024,614)					$ 723,707,661
Balance (in shares) at Dec. 31, 2013	35,221,941
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of employee common stock options, stock appreciation rights, and related tax benefits	$ 302,403					8,444,894					0					0					8,747,297
Exercise of employee common stock options, stock appreciation rights, and related tax benefits (in shares)	302,403
Issuance of restricted common shares, net of forfeitures	$ 277,187					(277,187)					0					0					0
Issuance of restricted common shares, net of forfeitures (in shares)	277,187
Common stock issued in conjunction with acquisition																					0
Restricted shares withheld for taxes	$ (69,048)					(2,256,560)					0					0					(2,325,608)
Restricted shares withheld for taxes (in shares)	(69,048)
Compensation expense for restricted shares	$ 0					5,308,167					0					0					5,308,167
Common dividends paid	0					0					(11,398,285)					0					(11,398,285)
Net income	0					0					70,471,167					0					70,471,167
Other comprehensive income (loss)	0					0					0					8,182,982					8,182,982
Balance at Dec. 31, 2014	$ 35,732,483					561,431,449					201,371,081					4,158,368					802,693,381
Balance (in shares) at Dec. 31, 2014	35,732,483
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of employee common stock options, stock appreciation rights, and related tax benefits	$ 304,313					7,187,629					0					0					7,491,942
Exercise of employee common stock options, stock appreciation rights, and related tax benefits (in shares)	304,313
Issuance of restricted common shares, net of forfeitures	$ 257,218					(257,218)					0					0					0
Issuance of restricted common shares, net of forfeitures (in shares)	257,218
Common stock issued in conjunction with acquisition				$ 3,306,184	$ 1,371,717				$ 202,648,875	$ 62,166,214				$ 0	$ 0				$ 0	$ 0	269,492,990			$ 205,955,059	$ 63,537,931
Common stock issued in conjunction with acquisition (in shares)				3,306,184	1,371,717
Restricted shares withheld for taxes	$ (65,851)					(901,502)					0					0					(967,353)
Restricted shares withheld for taxes (in shares)	(65,851)
Compensation expense for restricted shares	$ 0					7,341,603					0					0					7,341,603
Common dividends paid											(18,307,075)										(18,307,075)
Net income											95,509,402										95,509,402
Other comprehensive income (loss)											0					(7,643,590)					(7,643,590)
Balance at Dec. 31, 2015	$ 40,906,064					839,617,050					278,573,408					(3,485,222)					1,155,611,300
Balance (in shares) at Dec. 31, 2015	40,906,064
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of employee common stock options, stock appreciation rights, and related tax benefits	$ 699,810					16,736,365					0					0					17,436,175
Exercise of employee common stock options, stock appreciation rights, and related tax benefits (in shares)	699,810
Issuance of restricted common shares, net of forfeitures	$ 200,098					(200,098)					0					0					0
Issuance of restricted common shares, net of forfeitures (in shares)	200,098
Common stock issued in conjunction with acquisition		$ 860,470	$ 3,760,326				$ 38,833,566	$ 178,708,278				$ 0	$ 0				$ 0	$ 0			222,162,640	$ 39,694,036	$ 182,468,604
Common stock issued in conjunction with acquisition (in shares)		860,470	3,760,326
Restricted shares withheld for taxes	$ (67,391)					(1,175,282)					0					0					(1,242,673)
Restricted shares withheld for taxes (in shares)	(67,391)
Compensation expense for restricted shares	$ 0					10,970,849					0					0					10,970,849
Common dividends paid	0					0					(24,725,598)					0					(24,725,598)
Net income	0					0					127,224,695					0					127,224,695
Other comprehensive income (loss)	0					0					0					(10,741,276)					(10,741,276)
Balance at Dec. 31, 2016	$ 46,359,377					$ 1,083,490,728					$ 381,072,505					$ (14,226,498)					$ 1,496,696,112
Balance (in shares) at Dec. 31, 2016	46,359,377