INVESTMENT SECURITIES (Tables)

6 Months Ended

Jun. 30, 2019

INVESTMENT SECURITIES [Abstract]

Amortized Cost and Estimated Fair Value of Investment Securities

The amortized cost and estimated fair value of investment securities as of June 30, 2019 and December 31, 2018 are as follows:

	June 30, 2019								December 31, 2018
(000's omitted)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available-for-Sale Portfolio:
U.S. Treasury and agency securities	$	1,435,302	$	22,204	$	428	$	1,457,078	$	2,036,474	$	2,190	$	14,911	$	2,023,753
Obligations of state and political subdivisions		427,621		12,076		0		439,697		453,640		6,563		1,049		459,154
Government agency mortgage-backed securities		395,220		4,196		2,221		397,195		390,234		1,526		9,283		382,477
Corporate debt securities		2,558		0		4		2,554		2,588		0		42		2,546
Government agency collateralized mortgage obligations		61,996		586		68		62,514		69,342		60		1,283		68,119
Total available-for-sale portfolio	$	2,322,697	$	39,062	$	2,721	$	2,359,038	$	2,952,278	$	10,339	$	26,568	$	2,936,049
Equity and other Securities:
Equity securities, at fair value	$	251	$	199	$	0	$	450	$	251	$	200	$	19	$	432
Federal Home Loan Bank common stock		6,251		0		0		6,251		8,768		0		0		8,768
Federal Reserve Bank common stock		30,690		0		0		30,690		30,690		0		0		30,690
Other equity securities, at adjusted cost		5,093		750		0		5,843		4,969		750		0		5,719
Total equity and other securities	$	42,285	$	949	$	0	$	43,234	$	44,678	$	950	$	19	$	45,609

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 June 30, 2019

	Less than 12 Months						12 Months or Longer						Total
(000's omitted)		#	Fair Value		Gross Unrealized Losses			#	Fair Value		Gross Unrealized Losses			#	Fair Value		Gross Unrealized Losses
Available-for-Sale Portfolio:
U.S. Treasury and agency securities		0	$	0	$	0		19	$	188,692	$	428		19	$	188,692	$	428
Obligations of state and political subdivisions		0		0		0		1		516		0		1		516		0
Government agency mortgage-backed securities		6		4,551		6		142		192,786		2,215		148		197,337		2,221
Corporate debt securities		0		0		0		1		2,554		4		1		2,554		4
Government agency collateralized mortgage obligations		0		0		0		13		18,233		68		13		18,233		68
Total available-for-sale investment portfolio		6	$	4,551	$	6		176	$	402,781	$	2,715		182	$	407,332	$	2,721

As of December 31, 2018

	Less than 12 Months						12 Months or Longer						Total
(000's omitted)		#	Fair Value		Gross Unrealized Losses			#	Fair Value		Gross Unrealized Losses			#	Fair Value		Gross Unrealized Losses
Available-for-Sale Portfolio:
U.S. Treasury and agency securities		7	$	473,082	$	682		64	$	1,213,276	$	14,229		71	$	1,686,358	$	14,911
Obligations of state and political subdivisions		118		55,671		216		97		51,753		833		215		107,424		1,049
Government agency mortgage-backed securities		43		47,708		258		181		253,931		9,025		224		301,639		9,283
Corporate debt securities		0		0		0		1		2,546		42		1		2,546		42
Government agency collateralized mortgage obligations		1		66		0		41		63,112		1,283		42		63,178		1,283
Total available-for-sale investment portfolio		169	$	576,527	$	1,156		384	$	1,584,618	$	25,412		553	$	2,161,145	$	26,568
Equity and other Securities:
Equity securities, at fair value		1	$	82	$	19		0	$	0	$	0		1	$	82	$	19
Total equity and other securities		1	$	82	$	19		0	$	0	$	0		1	$	82	$	19

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

The amortized cost and estimated fair value of debt securities at June 30, 2019, 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
(000's omitted)	Amortized Cost		Fair Value
Due in one year or less	$	76,679	$	76,659
Due after one through five years		1,489,433		1,513,356
Due after five years through ten years		143,339		147,980
Due after ten years		156,030		161,334
Subtotal		1,865,481		1,899,329
Government agency mortgage-backed securities		395,220		397,195
Government agency collateralized mortgage obligations		61,996		62,514
Total	$	2,322,697	$	2,359,038