Investment Securities (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of amortized cost, gross unrealized gains, gross unrealized losses and approximate fair value of investment securities

The amortized cost, gross unrealized gains, gross unrealized losses and approximate market value of the Corporation's investment securities at the dates indicated were:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available for sale at September 30, 2017
U.S. Treasury	$	250					$	250
State and municipal	452,666		$	13,748	$	2,006	464,408
U.S. Government-sponsored mortgage-backed securities	423,390		2,242		1,957		423,675
Corporate obligations	31						31
Equity securities	2,357						2,357
Total available for sale	878,694		15,990		3,963		890,721
Held to maturity at September 30, 2017
U.S. Government-sponsored agency securities	22,618				311		22,307
State and municipal	237,257		5,935		575		242,617
U.S. Government-sponsored mortgage-backed securities	317,291		4,867		812		321,346
Foreign Investments	1,000						1,000
Total held to maturity	578,166		10,802		1,698		587,270
Total Investment Securities	$	1,456,860	$	26,792	$	5,661	$	1,477,991

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available for sale at December 31, 2016
U.S. Government-sponsored agency securities	$	100					$	100
State and municipal	360,779		$	8,443	$	5,564	363,658
U.S. Government-sponsored mortgage-backed securities	313,459		1,904		3,071		312,292
Corporate obligations	31						31
Equity securities	21,820				1,039		20,781
Total available for sale	696,189		10,347		9,674		696,862
Held to maturity at December 31, 2016
U.S. Government-sponsored agency securities	22,619				479		22,140
State and municipal	224,811		3,136		1,796		226,151
U.S. Government-sponsored mortgage-backed securities	360,213		4,956		1,527		363,642
Total held to maturity	607,643		8,092		3,802		611,933
Total Investment Securities	$	1,303,832	$	18,439	$	13,476	$	1,308,795

Schedule of amortized cost and fair value of available for sale securities and held to maturity securities

The amortized cost and fair value of available for sale and held to maturity securities at September 30, 2017 and December 31, 2016, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Maturity Distribution at September 30, 2017:
Due in one year or less	$	674	$	675	$	7,329	$	7,417
Due after one through five years	8,970		9,398		79,466		80,423
Due after five through ten years	84,977		88,832		53,423		54,573
Due after ten years	358,326		365,784		120,657		123,511
	$	452,947	$	464,689	$	260,875	$	265,924
U.S. Government-sponsored mortgage-backed securities	423,390		423,675		317,291		321,346
Equity securities	2,357		2,357
Total Investment Securities	$	878,694	$	890,721	$	578,166	$	587,270

	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Maturity Distribution at December 31, 2016
Due in one year or less	$	2,703	$	2,717	$	2,046	$	2,047
Due after one through five years	16,359		17,068		61,921		63,193
Due after five through ten years	60,614		62,241		61,606		61,145
Due after ten years	281,234		281,763		121,857		121,906
	$	360,910	$	363,789	$	247,430	$	248,291
U.S. Government-sponsored mortgage-backed securities	313,459		312,292		360,213		363,642
Equity securities	21,820		20,781
Total Investment Securities	$	696,189	$	696,862	$	607,643	$	611,933

Schedule of gross gains on sales and redemptions of available for sale securities

Gross gains on the sales and redemptions of available for sale securities for the three and nine months ended September 30, 2017 and 2016 are shown below.

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Sales and Redemptions of Available for Sale Securities:
Gross gains	$	382	$	839	$	1,547	$	2,542
Gross losses	50				50

Schedule of investment securities with unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position

The following tables show the Corporation’s gross unrealized losses and fair value, aggregated by investment category and length of time the individual securities have been in a continuous unrealized loss position at September 30, 2017, and December 31, 2016:

	Less than 12 Months				12 Months or Longer				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Temporarily Impaired Available for Sale Securities at September 30, 2017
State and municipal	$	76,469	$	959	$	21,693	$	1,047	$	98,162	$	2,006
U.S. Government-sponsored mortgage-backed securities	153,833		1,794		8,149		163		161,982		1,957
Total Temporarily Impaired Available for Sale Securities	230,302		2,753		29,842		1,210		260,144		3,963
Temporarily Impaired Held to Maturity Securities at September 30, 2017
U.S. Government-sponsored agency securities	9,941		78		12,267		233		22,208		311
State and municipal	18,754		402		6,216		173		24,970		575
U.S. Government-sponsored mortgage-backed securities	74,950		812						74,950		812
Total Temporarily Impaired Held to Maturity Securities	103,645		1,292		18,483		406		122,128		1,698
Total Temporarily Impaired Investment Securities	$	333,947	$	4,045	$	48,325	$	1,616	$	382,272	$	5,661

	Less than 12 Months				12 Months or Longer		Total
	Fair Value		Gross Unrealized Losses		Fair Value	Gross Unrealized Losses	Fair Value		Gross Unrealized Losses
Temporarily Impaired Available for Sale Securities at December 31, 2016
State and municipal	$	126,593	$	5,564			$	126,593	$	5,564
U.S. Government-sponsored mortgage-backed securities	185,544		3,071				185,544		3,071
Equity Securities	18,765		1,039				18,765		1,039
Total Temporarily Impaired Available for Sale Securities	330,902		9,674				330,902		9,674
Temporarily Impaired Held to Maturity Securities at December 31, 2016
U.S. Government-sponsored agency securities	19,121		479				19,121		479
State and municipal	50,897		1,796				50,897		1,796
U.S. Government-sponsored mortgage-backed securities	109,377		1,527				109,377		1,527
Total Temporarily Impaired Held to Maturity Securities	179,395		3,802				179,395		3,802
Total Temporarily Impaired Investment Securities	$	510,297	$	13,476			$	510,297	$	13,476

Schedule of investments in debt and equity securities reported in the financial statements at an amount less than their historical cost

Certain investments in debt and equity securities are reported in the financial statements at an amount less than their historical cost as indicated in the table below.

	September 30, 2017			December 31, 2016
Investments reported at less than historical cost:
Historical cost	$	388,181		$	523,773
Fair value	$	382,272		$	510,297
Percent of the Corporation's investment portfolio	26.0		%	39.1		%