Summary of Significant Accounting Policies (Details) - USD ($)		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Cash Transactions [Abstract]
Interest paid		$ 13,666,769	$ 7,341,784
Income taxes paid		230,110	10,556,737
Noncash Transactions [Abstract]
Loans charged-off to the allowance for loan losses		5,161,951	9,226,906
Loans foreclosed upon with repossessions transferred to other real estate		1,498,198	0
Loans foreclosed upon and transferred to other assets		2,593	1,384,511
Common stock issued in connection with acquisitions		0	39,694,036
Basic net income per share calculation [Abstract]
Numerator - Net income		$ 39,653,047	$ 27,965,264
Denominator - Average common shares outstanding (in shares)		48,022,342	40,082,805
Basic net income per share (in dollars per share)		$ 0.83	$ 0.70
Diluted net income per share calculation [Abstract]
Numerator - Net income		$ 39,653,047	$ 27,965,264
Denominator - Average common shares outstanding (in shares)		48,022,342	40,082,805
Dilutive shares (in shares)	[1]	495,578	764,222
Average diluted common shares outstanding (in shares)		48,517,920	40,847,027
Diluted net income per share (in dollars per share)		$ 0.82	$ 0.68
Bankers Healthcare Group, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage equity method investment		49.00%

[1] Approximately 518,152 restricted share units are not included in the weighted-average shares outstanding as they are deemed to be contingently issuable. Additionally, for the periods ended September 30, 2016 and 2015, there were no anti-dilutive share-based awards outstanding.