Investment Securities (Tables)

6 Months Ended

Jun. 30, 2022

Summary of Amortized Cost and Estimated Fair Values of Available for Sale Securities

The amortized cost, estimated fair values, and allowance for credit losses of securities available for sale are summarized as follows.

	June 30, 2022
			Gross		Gross		Allowance		Estimated
	Amortized		Unrealized		Unrealized		For Credit		Fair
	Cost		Gains		Losses		Losses		Value
U.S. Treasury securities and obligations of U.S. Government corporations and agencies	$	502,730	$	534	$	10,008	$	0	$	493,256
State and political subdivisions		836,622		240		85,785		0		751,077
Residential mortgage-backed securities
Agency		1,424,937		178		130,114		0		1,295,001
Non-agency		114,692		198		6,252		0		108,638
Commercial mortgage-backed securities
Agency		686,470		17		44,897		0		641,590
Asset-backed securities		953,347		15		35,738		0		917,624
Single issue trust preferred securities		17,316		2		1,115		0		16,203
Other corporate securities		617,171		141		27,997		0		589,315
Total	$	5,153,285	$	1,325	$	341,906	$	0	$	4,812,704

	December 31, 2021
			Gross		Gross		Allowance		Estimated
	Amortized		Unrealized		Unrealized		For Credit		Fair
	Cost		Gains		Losses		Losses		Value
U.S. Treasury securities and obligations of U.S. Government corporations and agencies	$	82,136	$	51	$	337	$	0	$	81,850
State and political subdivisions		831,499		19,608		3,809		0		847,298
Residential mortgage-backed securities
Agency		1,120,423		9,173		15,822		0		1,113,774
Non-agency		74,965		306		726		0		74,545
Commercial mortgage-backed securities
Agency		633,802		12,731		6,608		0		639,925
Asset-backed securities		659,830		49		3,307		0		656,572
Single issue trust preferred securities		17,291		146		626		0		16,811
Other corporate securities		611,548		3,558		3,182		0		611,924
Total	$	4,031,494	$	45,622	$	34,417	$	0	$	4,042,699

Summary of Securities Available for Sale in an Unrealized Loss Position

The following is a summary of securities available for sale which were in an unrealized loss position at June 30, 2022 and December 31, 2021.

	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
June 30, 2022
U.S. Treasury securities and obligations of U.S. Government corporations and agencies	$	383,535	$	10,005	$	170	$	3	$	383,705	$	10,008
State and political subdivisions		670,707		76,647		40,051		9,138		710,758		85,785
Residential mortgage-backed securities
Agency		1,051,557		93,467		216,233		36,647		1,267,790		130,114
Non-agency		67,293		3,187		17,347		3,065		84,640		6,252
Commercial mortgage-backed securities
Agency		541,440		27,157		92,340		17,740		633,780		44,897
Asset-backed securities		776,828		30,045		134,998		5,693		911,826		35,738
Single issue trust preferred securities		0		0		13,123		1,115		13,123		1,115
Other corporate securities		487,011		26,433		30,839		1,564		517,850		27,997
Total	$	3,978,371	$	266,941	$	545,101	$	74,965	$	4,523,472	$	341,906

	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
December 31, 2021
U.S. Treasury securities and obligations of U.S. Government corporations and agencies	$	75,106	$	334	$	213	$	3	$	75,319	$	337
State and political subdivisions		223,754		2,872		24,067		937		247,821		3,809
Residential mortgage-backed securities
Agency		680,320		13,167		71,392		2,655		751,712		15,822
Non-agency		55,336		726		0		0		55,336		726
Commercial mortgage-backed securities
Agency		136,071		2,912		70,543		3,696		206,614		6,608
Asset-backed securities		532,373		2,620		82,222		687		614,595		3,307
Single issue trust preferred securities		0		0		13,594		626		13,594		626
Other corporate securities		307,912		3,182		0		0		307,912		3,182
Total	$	2,010,872	$	25,813	$	262,031	$	8,604	$	2,272,903	$	34,417

Summary of Gains or Losses on Proceeds from Maturities, Sales and Calls of Available for Sale Securities by Specific Identification Method

	Three Months Ended June 30				Six Months Ended June 30
	2022		2021		2022		2021
Proceeds from sales and calls	$	150,915	$	131,464	$	302,542	$	400,993
Gross realized gains		0		0		0		1,542
Gross realized losses		0		0		0		98

Summary of Maturities of Debt Securities Held to Maturity by Amortized Cost and Estimated Fair Value

	June 30, 2022				December 31, 2021
			Estimated				Estimated
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
Due in one year or less	$	292,926	$	290,619	$	126,032	$	126,564
Due after one year through five years		965,407		943,395		661,627		670,298
Due after five years through ten years		986,624		901,478		940,031		941,640
Due after ten years		2,908,328		2,677,212		2,303,804		2,304,197
Total	$	5,153,285	$	4,812,704	$	4,031,494	$	4,042,699

Summary of Equity Securities

	Three Months Ended June 30					Six Months Ended June 30
	2022			2021		2022			2021
Net gains recognized during the period on equity securities sold	$	0		$	0	$	0		$	788
Unrealized gains recognized during the period on equity securities still held at period end		6			24		25			51
Unrealized losses recognized during the period on equity securities still held at period end		(188	)		0		(458	)		(105	)
Net (losses) gains recognized during the period	$	(182	)	$	24	$	(433	)	$	734