Investment Securities Available for Sale and Investment Securities Held to Maturity

The following table presents the adjusted cost and approximate fair value of investment securities available for sale and investment securities held to maturity.



	March 31, 2016
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
	(In Thousands)
Investment securities available for sale:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	2,702,503	$	29,519	$	12,676	$	2,719,346
Mortgage-backed securities	4,562,638		31,203		23,016		4,570,825
Collateralized mortgage obligations	3,474,587		22,901		11,327		3,486,161
States and political subdivisions	14,043		242		—		14,285
Other	19,054		336		32		19,358
Equity securities	455,780		42		—		455,822
Total	$	11,228,605	$	84,243	$	47,051	$	11,265,797
Investment securities held to maturity:
Collateralized mortgage obligations	$	98,642	$	4,435	$	8,111	$	94,966
Asset-backed securities	21,447		2,464		1,657		22,254
States and political subdivisions	1,081,227		1,407		64,644		1,017,990
Other	66,637		2,115		2,130		66,622
Total	$	1,267,953	$	10,421	$	76,542	$	1,201,832



	December 31, 2015
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
	(In Thousands)
Investment securities available for sale:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	3,232,238	$	4,076	$	24,822	$	3,211,492
Mortgage-backed securities	4,624,441		16,548		50,727		4,590,262
Collateralized mortgage obligations	2,713,075		8,200		16,019		2,705,256
States and political subdivisions	15,492		395		—		15,887
Other	23,914		175		44		24,045
Equity securities	503,540		38		—		503,578
Total	$	11,112,700	$	29,432	$	91,612	$	11,050,520
Investment securities held to maturity:
Collateralized mortgage obligations	$	103,947	$	6,022	$	4,634	$	105,335
Asset-backed securities	24,011		3,002		1,574		25,439
States and political subdivisions	1,128,240		729		82,632		1,046,337
Other	66,478		2,644		2,112		67,010
Total	$	1,322,676	$	12,397	$	90,952	$	1,244,121

In the above table, equity securities include $456 million and $503 million at March 31, 2016 and December 31, 2015, respectively, of FHLB and Federal Reserve stock carried at par.

The investments held within the states and political subdivision caption of investment securities held to maturity relate to private placement transactions underwritten as loans by the Company but that meet the definition of a security within ASC Topic 320, Investments – Debt and Equity Securities.

The following table discloses the fair value and the gross unrealized losses of the Company’s available for sale securities and held to maturity securities that were in a loss position at March 31, 2016 and December 31, 2015. This information is aggregated by investment category and the length of time the individual securities have been in an unrealized loss position.



	March 31, 2016
	Securities in a loss position for less than 12 months				Securities in a loss position for 12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In Thousands)
Investment securities available for sale:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	267,701	$	2,479	$	566,514	$	10,197	$	834,215	$	12,676
Mortgage-backed securities	597,351		3,571		1,640,437		19,445		2,237,788		23,016
Collateralized mortgage obligations	802,835		6,708		427,581		4,619		1,230,416		11,327
Other	—		—		1,090		32		1,090		32
Total	$	1,667,887	$	12,758	$	2,635,622	$	34,293	$	4,303,509	$	47,051

Investment securities held to maturity:
Collateralized mortgage obligations	$	13,981	$	1,698	$	48,902	$	6,413	$	62,883	$	8,111
Asset-backed securities	—		—		13,829		1,657		13,829		1,657
States and political subdivisions	19,569		2,081		829,864		62,563		849,433		64,644
Other	—		—		3,983		2,130		3,983		2,130
Total	$	33,550	$	3,779	$	896,578	$	72,763	$	930,128	$	76,542



	December 31, 2015
	Securities in a loss position for less than 12 months				Securities in a loss position for 12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In Thousands)
Investment securities available for sale:
Debt securities:
U.S. Treasury and other U.S. government agencies	$	2,081,528	$	16,523	$	460,160	$	8,299	$	2,541,688	$	24,822
Mortgage-backed securities	2,623,761		20,380		1,408,069		30,347		4,031,830		50,727
Collateralized mortgage obligations	1,321,121		10,378		393,210		5,641		1,714,331		16,019
Other	—		—		1,078		44		1,078		44
Total	$	6,026,410	$	47,281	$	2,262,517	$	44,331	$	8,288,927	$	91,612

Investment securities held to maturity:
Collateralized mortgage obligations	$	11,066	$	326	$	52,601	$	4,308	$	63,667	$	4,634
Asset-backed securities	—		—		15,790		1,574		15,790		1,574
States and political subdivisions	73,302		6,533		794,489		76,099		867,791		82,632
Other	—		—		4,015		2,112		4,015		2,112
Total	$	84,368	$	6,859	$	866,895	$	84,093	$	951,263	$	90,952

As indicated in the previous tables, at March 31, 2016, the Company held certain investment securities in unrealized loss positions. The Company does not have the intent to sell these securities and believes it is not more likely than not that it will be required to sell these securities before their anticipated recovery.

The Company regularly evaluates each available for sale and held to maturity security in a loss position for OTTI. In its evaluation, the Company considers such factors as the length of time and the extent to which the fair value has been below cost, the financial condition of the issuer, the Company’s intent to hold the security to an expected recovery in market value and whether it is more likely than not that the Company will have to sell the security before its fair value recovers. Activity related to the credit loss component of the OTTI is recognized in earnings. The portion of OTTI related to all other factors is recognized in other comprehensive income.

Management does not believe that any individual unrealized loss in the Company’s investment securities available for sale or held to maturity portfolios, presented in the preceding tables, represents an OTTI at either March 31, 2016 or December 31, 2015, other than those noted below.

The following table discloses activity related to credit losses for debt securities where a portion of the OTTI was recognized in other comprehensive income.



	Three Months Ended March 31,
	2016		2015
	(In Thousands)
Balance at beginning of period	$	22,452	$	21,123
Reductions for securities paid off during the period (realized)	—		—
Additions for the credit component on debt securities in which OTTI was not previously recognized	—		—
Additions for the credit component on debt securities in which OTTI was previously recognized	—		285
Balance at end of period	$	22,452	$	21,408

For the three months ended March 31, 2016 there was no OTTI recognized on securities. For the three months ended March 31, 2015, there was $285 thousand of OTTI recognized on held to maturity securities. The investment securities primarily impacted by credit impairment are held to maturity non-agency collateralized mortgage obligations and asset-backed securities.

The maturities of the securities portfolios are presented in the following table.



March 31, 2016	Amortized Cost		Fair Value
	(In Thousands)
Investment securities available for sale:
Maturing within one year	$	136,663	$	136,678
Maturing after one but within five years	1,259,762		1,281,452
Maturing after five but within ten years	207,967		213,414
Maturing after ten years	1,131,208		1,121,445
	2,735,600		2,752,989
Mortgage-backed securities and collateralized mortgage obligations	8,037,225		8,056,986
Equity securities	455,780		455,822
Total	$	11,228,605	$	11,265,797

Investment securities held to maturity:
Maturing within one year	$	—	$	—
Maturing after one but within five years	328,302		319,491
Maturing after five but within ten years	238,245		217,907
Maturing after ten years	602,764		569,468
	1,169,311		1,106,866
Collateralized mortgage obligations	98,642		94,966
Total	$	1,267,953	$	1,201,832

The gross realized gains and losses recognized on sales of investment securities available for sale are shown in the table below.



	Three Months Ended March 31,
	2016		2015
	(In Thousands)
Gross gains	$	8,353	$	32,832
Gross losses	—		—
Net realized gains	$	8,353	$	32,832