Investment Securities (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Securities Available-for-Sale

The amortized cost and estimated fair value of securities available-for-sale and the corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive income at December 31, 2018 and 2017 were as follows:

			Gross		Gross
	Amortized		Unrealized		Unrealized
2018	Cost		Gains		Losses		Fair Value
Securities available-for-sale
Obligations of U.S.
Government agencies	$	99,365,930	$	—	$	3,388,147	$	95,977,783
Mortgage-backed securities		259,742,501		4,921		12,373,269		247,374,153
State, County, Municipals		105,590,858		67,888		4,264,228		101,394,518
Total	$	464,699,289	$	72,809	$	20,025,644	$	444,746,454

			Gross		Gross
	Amortized		Unrealized		Unrealized
2017	Cost		Gains		Losses		Fair Value
Securities available-for-sale
Obligations of U.S.
Government agencies	$	180,647,580	$	—	$	4,199,022	$	176,448,558
Mortgage-backed securities		213,707,125		43,197		5,327,265		208,423,057
State, County, Municipals		118,786,297		849,364		2,535,126		117,100,535
Other investments		2,865,294		208,933		—		3,074,227
Total	$	516,006,296	$	1,101,494	$	12,061,413	$	505,046,377

Summary of Unrealized Loss Information for Available-for-sale Securities

A summary of unrealized loss information for AFS securities, categorized by security type follows (in thousands):

December 31, 2018	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
Description of Securities	Value		Losses		Value		Losses		Value		Losses
Obligations of U.S.
Government agencies	$	—		—	$	95,977,783		3,388,147	$	95,977,783		3,388,147
Mortgage backed securities		12,257,636		179,281		234,928,705		12,193,988		247,186,341		12,373,269
State, County, Municipal		12,623,964		285,275		76,535,741		3,978,953		89,159,705		4,264,228
Total	$	24,881,600		464,556	$	407,442,229		19,561,088	$	432,323,829		20,025,644

December 31, 2017	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
Description of Securities	Value		Losses		Value		Losses		Value		Losses
Obligations of U.S.
Government agencies	$	15,681,866		223,535	$	160,766,691		3,975,487	$	176,448,557		4,199,022
Mortgage backed securities		88,499,852		1,613,091		116,753,236		3,714,175		205,253,088		5,327,266
State, County, Municipal		7,117,600		59,041		66,973,174		2,476,084		74,090,774		2,535,125
Total	$	111,299,318		1,895,667	$	344,493,101		10,165,746	$	455,792,419		12,061,413

Amortized Cost and Estimated Fair Value of Securities by Contractual Maturity

The amortized cost and estimated fair value of securities at December 31, 2018, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Amortized
	Cost		Fair Value
Securities AFS
Due in one year or less	$	1,875,288	$	1,877,665
Due after one year through five years		91,948,838		89,121,194
Due after five years through ten years		32,801,788		31,718,293
Due after ten years		78,330,873		74,655,149
Residential mortgage backed securities		187,776,954		179,235,806
Commercial mortgage backed securities		71,965,548		68,138,347
Total	$	464,699,289	$	444,746,454

Total Gross Realized Gains and Gross Realized Losses from Sale of Investment Securities

Total gross realized gains and gross realized losses from the sale of investment securities for each of the years ended December 31 were:

	2018		2017		2016
Gross realized gains	$	171,376	$	633,244	$	112,881
Gross realized losses		160,329		528,536		—
Net realized gains	$	11,047	$	104,708	$	112,881