INVESTMENT SECURITIES (Tables)

9 Months Ended

Sep. 30, 2020

INVESTMENT SECURITIES

Amortized Cost and Estimated Fair Value of Investment Securities

The amortized cost and estimated fair value of investment securities as of September 30, 2020 and December 31, 2019 are as follows:

	September 30, 2020								December 31, 2019
			Gross		Gross				Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
(000's omitted)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
Available-for-Sale Portfolio:
U.S. Treasury and agency securities	$	2,034,512	$	114,658	$	0	$	2,149,170	$	2,030,060	$	21,674	$	7,975	$	2,043,759
Obligations of state and political subdivisions		470,518		22,978		0		493,496		497,852		14,382		26		512,208
Government agency mortgage-backed securities		508,738		15,514		278		523,974		428,491		5,478		1,107		432,862
Corporate debt securities		4,504		98		0		4,602		2,527		1		0		2,528
Government agency collateralized mortgage obligations		50,134		1,354		8		51,480		52,621		482		32		53,071
Total available-for-sale portfolio	$	3,068,406	$	154,602	$	286	$	3,222,722	$	3,011,551	$	42,017	$	9,140	$	3,044,428
Equity and other Securities:
Equity securities, at fair value	$	251	$	192	$	20	$	423	$	251	$	200	$	0	$	451
Federal Home Loan Bank common stock		7,545		0		0		7,545		7,246		0		0		7,246
Federal Reserve Bank common stock		33,916		0		0		33,916		30,922		0		0		30,922
Other equity securities, at adjusted cost		4,707		750		0		5,457		4,546		750		0		5,296
Total equity and other securities	$	46,419	$	942	$	20	$	47,341	$	42,965	$	950	$	0	$	43,915

Summary of Investment Securities That Have Been in a Continuous Unrealized Loss Position for Less Than or Greater Than Twelve Months

A summary of investment securities that have been in a continuous unrealized loss position is as follows:

As of September 30, 2020

	Less than 12 Months						12 Months or Longer					Total
				Gross					Gross					Gross
		Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
(000's omitted)	#	Value		Losses		#	Value		Losses		#	Value		Losses
Available-for-Sale Portfolio:
U.S. Treasury and agency securities	1	$	1,010	$	0	0	$	0	$	0	1	$	1,010	$	0
Obligations of state and political subdivisions	1		196		0	0		0		0	1		196		0
Government agency mortgage-backed securities	91		62,318		278	2		14		0	93		62,332		278
Government agency collateralized mortgage obligations	14		4,244		8	1		0		0	15		4,244		8
Total available-for-sale investment portfolio	107	$	67,768	$	286	3	$	14	$	0	110	$	67,782	$	286
Equity and other Securities:
Equity securities, at fair value	1	$	81	$	20	0	$	0	$	0	1	$	81	$	20
Total equity and other securities	1	$	81	$	20	0	$	0	$	0	1	$	81	$	20

As of December 31, 2019

	Less than 12 Months					12 Months or Longer					Total
				Gross					Gross					Gross
		Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
(000's omitted)	#	Value		Losses		#	Value		Losses		#	Value		Losses
Available-for-Sale Portfolio:
U.S. Treasury and agency securities	12	$	592,678	$	7,970	5	$	25,998	$	5	17	$	618,676	$	7,975
Obligations of state and political subdivisions	21		22,716		26	0		0		0	21		22,716		26
Government agency mortgage-backed securities	50		89,237		341	52		52,975		766	102		142,212		1,107
Government agency collateralized mortgage obligations	5		5,971		14	5		4,405		18	10		10,376		32
Total available-for-sale investment portfolio	88	$	710,602	$	8,351	62	$	83,378	$	789	150	$	793,980	$	9,140

Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity

The amortized cost and estimated fair value of debt securities at September 30, 2020, 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. Securities not due at a single maturity date are shown separately.

	Available-for-Sale
	Amortized		Fair
(000's omitted)	Cost		Value
Due in one year or less	$	760,019	$	765,009
Due after one through five years		802,750		843,487
Due after five years through ten years		461,012		503,778
Due after ten years		485,753		534,994
Subtotal		2,509,534		2,647,268
Government agency mortgage-backed securities		508,738		523,974
Government agency collateralized mortgage obligations		50,134		51,480
Total	$	3,068,406	$	3,222,722