(3) AVAILABLE-FOR-SALE SECURITIES

A comparison of amortized cost and estimated fair values of available-for-sale securities as of December 31, 2016 and 2015 follows:


	2016
		Gross	Gross	Estimated
	Amortized	Unrealized	Unrealized	Fair
	Cost	Gains	Losses	Value
	(In thousands)
U.S. Government agencies	$ 1,794,231	$ 1,261	$ 6,065	$ 1,789,427
U.S. Government agency issued residential
mortgage-backed securities	176,476	1,665	1,898	176,243
U.S. Government agency issued commercial
mortgage-backed securities	171,840	1,648	1,209	172,279
Obligations of states and political subdivisions	346,609	15,547	2,151	360,005
FHLB and other securities	32,436	1,286	-	33,722
Total	$ 2,521,592	$ 21,407	$ 11,323	$ 2,531,676

	2015
		Gross	Gross	Estimated
	Amortized	Unrealized	Unrealized	Fair
	Cost	Gains	Losses	Value
	(In thousands)
U.S. Government agencies	$ 1,246,261	$ 826	$ 2,447	$ 1,244,640
U.S. Government agency issued residential
mortgage-backed securities	138,759	1,957	176	140,540
U.S. Government agency issued commercial
mortgage-backed securities	261,544	2,414	3,265	260,693
Obligations of states and political subdivisions	394,769	22,813	83	417,499
FHLB and other securities	18,112	845	-	18,957
Total	$ 2,059,445	$ 28,855	$ 5,971	$ 2,082,329

At December 31, 2016, the Company’s available-for-sale securities included FHLB stock with a carrying value of $32.3 million compared to a required investment of $31.0 million. At December 31, 2015, the Company’s available-for-sale securities included FHLB stock with a carrying value of $18.0 million compared to a required investment of $9.1 million. FHLB stock is carried at cost in the financial statements.

Gross gains of approximately $128,000 and no gross losses were recognized in 2016, gross gains of approximately $136,000 and no gross losses were recognized in 2015 and gross gains of approximately $49,000 and gross losses of approximately $12,000 were recognized in 2014 on available-for-sale securities. No other-than-temporary impairment was recorded in 2016, 2015 or 2014.

Available-for-sale securities with a carrying value of $1.6 billion at December 31, 2016 were pledged to secure public and trust funds on deposit and for other purposes. Included in available-for-sale securities at December 31, 2016, were securities with a carrying value of $183.0 million issued by a political subdivision within the State of Mississippi and securities with a carrying value of $54.1 million issued by a political subdivision within the State of Arkansas.

The amortized cost and estimated fair value of available-for-sale securities at December 31, 2016 by contractual maturity are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Equity securities are considered as maturing after ten years.


		Estimated	Weighted
	Amortized	Fair	Average
	Cost	Value	Yield
	(Dollars in thousands)
Maturing in one year or less	$ 548,060	$ 548,347	0.96	%
Maturing after one year through five years	1,331,619	1,326,489	1.30
Maturing after five years through ten years	53,517	54,418	5.71
Maturing after ten years	240,080	253,900	5.47
Mortgage-backed securities	348,316	348,522	2.13
Total	$ 2,521,592	$ 2,531,676

A summary of temporarily impaired available-for-sale investments with continuous unrealized loss positions at December 31, 2016 and 2015 follows:


	2016
	Less Than 12 Months		12 Months or Longer		Total
	Fair	Unrealized	Fair	Unrealized	Fair	Unrealized
	Value	Losses	Value	Losses	Value	Losses
	(In thousands)
U.S. Government agencies	$ 1,082,573	$ 6,065	$ -	$ -	$ 1,082,573	$ 6,065
U.S. Government agency issued residential
mortgage-backed securities	71,599	1,783	15,375	115	86,974	1,898
U.S. Government agency issued commercial
mortgage-backed securities	129,940	1,084	14,385	125	144,325	1,209
Obligations of states and political subdivisions	46,798	2,151	-	-	46,798	2,151
Total	$ 1,330,910	$ 11,083	$ 29,760	$ 240	$ 1,360,670	$ 11,323

	2015
	Less Than 12 Months		12 Months or Longer		Total
	Fair	Unrealized	Fair	Unrealized	Fair	Unrealized
	Value	Losses	Value	Losses	Value	Losses
	(In thousands)
U.S. Government agencies	$ 762,568	$ 2,447	$ -	$ -	$ 762,568	$ 2,447
U.S. Government agency issued residential
mortgage-backed securities	34,238	176	-	-	34,238	176
U.S. Government agency issued commercial
mortgage-backed securities	193,621	2,710	31,166	555	224,787	3,265
Obligations of states and political subdivisions	13,576	70	2,856	13	16,432	83
Total	$ 1,004,003	$ 5,403	$ 34,022	$ 568	$ 1,038,025	$ 5,971

Based upon a review of the credit quality of these securities, and considering that the issuers were in compliance with the terms of the securities, management has no intent to sell these securities until the full recovery of unrealized losses, which may be until maturity, and it was more likely than not that the Company would not be required to sell the securities prior to recovery of costs. Therefore, the impairments related to these securities were determined to be temporary. No other-than-temporary impairment was recorded in 2016 or 2015.