Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Cash Transactions [Abstract]
Interest paid			$ 11,807,394	$ 10,186,045
Income taxes paid, net			30,186,000	22,150,000
Noncash Transactions:
Loans charged-off to the allowance for loan losses			11,732,626	5,634,327	$ 7,703,000
Loans foreclosed upon and transferred to other real estate owned			252,896	1,672,459
Loans foreclosed upon and transferred to other repossessed assets			5,947,634	1,398,823
Available-for-sale securities transferred to held-to-maturity portfolio			0	0
Basic net income per share calculation [Abstract]
Numerator - Net income	$ 24,148,752	$ 18,196,822	$ 68,655,294	$ 51,733,929
Denominator - Average common shares outstanding (in shares)	37,828,329	34,762,206	36,009,659	34,688,064
Basic net income per share (in dollars per share)	$ 0.64	$ 0.52	$ 1.91	$ 1.49
Diluted earnings per share calculation [Abstract]
Numerator - Net income	$ 24,148,752	$ 18,196,822	$ 68,655,294	$ 51,733,929
Denominator - Average common shares outstanding (in shares)	37,828,329	34,762,206	36,009,659	34,688,064
Dilutive shares contingently issuable (in shares)	964,458	393,018	934,512	381,700
Average diluted common shares outstanding (in shares)	38,792,787	35,155,224	36,944,171	35,069,764
Diluted net income per share (in dollars per share)	$ 0.62	$ 0.52	$ 1.86	$ 1.48
Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument, principal amount	$ 60,000,000		$ 60,000,000
Debt instrument, redemption price as percentage of principal amount redeemed			100.00%
Debt instrument, interest rate	4.875%		4.875%
Net proceeds from issuance debt			$ 59,100,000
Subordinated Notes [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate			3.128%