Note 3. Securities

At March 31, 2015, the Company had total securities of $8.73 billion, comprised of securities available-for-sale at fair value of $5.21 billion, securities held-to-maturity at amortized cost of $3.41 billion and trading securities at fair value of $102.5 million. At December 31, 2014, the Company had total securities of $9.48 billion, comprised of securities available-for-sale at fair value of $5.88 billion, securities held-to-maturity at amortized cost of $3.43 billion and trading securities at fair value of $173.2 million.

The following is a summary of amortized cost and estimated fair value for the major categories of securities available-for-sale and securities held-to-maturity at March 31, 2015 and December 31, 2014:

			Gross		Gross
	Amortized		Unrealized		Unrealized
(in thousands)	Cost		Gains		Losses			Fair Value
March 31, 2015
Securities available-for-sale:
U.S. Treasury	$	115,893	$	29	$	(15	)	$	115,907
Federal agency - Debt	1,219,481		1,168		(429		)	1,220,220
Federal agency - MBS	99,891		2,498		(874		)	101,515
CMOs - Federal agency	3,204,823		22,016		(21,953		)	3,204,886
CMOs - Non-agency	23,147		24		(360		)	22,811
State and municipal	421,419		6,257		(218		)	427,458
Other debt securities	115,006		1,438		(3		)	116,441
Total debt securities	5,199,660		33,430		(23,852		)	5,209,238
Equity securities and mutual funds	1,341		219		(410		)	1,150
Total securities available-for-sale	$	5,201,001	$	33,649	$	(24,262	)	$	5,210,388

Securities held-to-maturity (1):
Federal agency - Debt	$	286,581	$	9,923	$	(72	)	$	296,432
Federal agency - MBS	556,931		20,346		(567		)	576,710
CMOs - Federal agency	1,766,325		48,270		(2,749		)	1,811,846
State and municipal	717,937		23,084		(1,810		)	739,211
Other debt securities	86,032		322		—			86,354
Total securities held-to-maturity	$	3,413,806	$	101,945	$	(5,198	)	$	3,510,553

December 31, 2014
Securities available-for-sale:
U.S. Treasury	$	116,919	$	17	$	(10	)	$	116,926
Federal agency - Debt	1,401,303		558		(3,280		)	1,398,581
Federal agency - MBS	102,939		2,601		(1,014		)	104,526
CMOs - Federal agency	3,599,831		19,628		(38,869		)	3,580,590
CMOs - Non-agency	24,385		40		(411		)	24,014
State and municipal	473,272		6,139		(380		)	479,031
Other debt securities	174,352		1,817		—			176,169
Total debt securities	5,893,001		30,800		(43,964		)	5,879,837
Equity securities and mutual funds	1,508		1,988		(350		)	3,146
Total securities available-for-sale	$	5,894,509	$	32,788	$	(44,314	)	$	5,882,983

Securities held-to-maturity (1):
Federal agency - Debt	$	292,932	$	6,430	$	(255	)	$	299,107
Federal agency - MBS	553,589		13,427		(2,275		)	564,741
CMOs - Federal agency	1,811,574		29,998		(10,292		)	1,831,280
State and municipal	682,705		22,732		(1,997		)	703,440
Other debt securities	86,231		72		(224		)	86,079
Total securities held-to-maturity	$	3,427,031	$	72,659	$	(15,043	)	$	3,484,647

(1)

Securities held-to-maturity are presented in the consolidated balance sheets at amortized cost.

Proceeds from sales of securities available-for-sale were $398.2 million for the three months ended March 31, 2015, compared with $377.1 million for the three months ended March 31, 2014. There were no sales of securities held-to-maturity during the three months ended March 31, 2015 and 2014. The following table provides the gross realized gains and losses on the sales and calls of securities (including trading securities):

	For the three months ended
	March 31,
(in thousands)	2015			2014
Gross realized gains	$	3,392		$	2,602
Gross realized losses	(16		)	(480		)
Net realized gains	$	3,376		$	2,122

Interest income on securities for the three months ended March 31, 2015 and 2014 is comprised of: (i) taxable interest income of $35.0 million and $36.0 million, respectively, (ii) nontaxable interest income of $7.0 million and $5.5 million, respectively, and (iii) dividend income of $11 thousand and $9 thousand, respectively.

The following table provides the expected remaining maturities of debt securities included in the securities portfolio at March 31, 2015, except for maturities of mortgage-backed securities which are allocated according to the average life of expected cash flows. Average expected maturities will differ from contractual maturities because of the amortizing nature of the loan collateral and prepayment behavior of borrowers.

(in thousands)	One year or less		Over 1 year through 5 years		Over 5 years through 10 years		Over 10 years		Total

Securities available-for-sale:
U.S. Treasury	$	98,400	$	17,507	$	—	$	—	$	115,907
Federal agency - Debt	597,445		622,775		—		—		1,220,220
Federal agency - MBS	—		83,971		17,544		—		101,515
CMOs - Federal agency	157,341		3,047,545		—		—		3,204,886
CMOs - Non-agency	1,381		21,430		—		—		22,811
State and municipal	171,999		252,104		—		3,355		427,458
Other	57,142		59,299		—		—		116,441
Total debt securities available-for-sale	$	1,083,708	$	4,104,631	$	17,544	$	3,355	$	5,209,238

Amortized cost	$	1,081,124	$	4,097,536	$	17,600	$	3,400	$	5,199,660

Securities held-to-maturity:
Federal agency - Debt	$	—	$	—	$	132,829	$	153,752	$	286,581
Federal agency - MBS	—		49,153		503,264		4,514		556,931
CMOs - Federal agency	—		867,361		898,964		—		1,766,325
State and municipal	—		177,608		454,244		86,085		717,937
Other	—		86,032		—		—		86,032
Total debt securities held-to-maturity at amortized cost	$	—	$	1,180,154	$	1,989,301	$	244,351	$	3,413,806

Impairment Assessment

The Company performs a quarterly assessment of debt and equity securities in its investment portfolio to determine whether a decline in fair value below amortized cost is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for amortization, accretion, collection of cash and previous other-than-temporary impairment recognized in earnings. The Company’s impairment assessment of debt securities takes the following factors into consideration: the length of time and the extent to which the market value has been less than cost; the financial condition and near-term prospects of the issuer, including events specific to the issuer or industry; defaults or deferrals of scheduled interest and principal payments; external credit ratings; and whether the Company intends to sell the security or more likely than not will be required to sell the security before recovery of its amortized cost basis. For equity securities, the evaluation of whether an impairment is other-than-temporary is based on whether and when an equity security will recover in value and whether the Company has the intent and ability to hold the equity security until the anticipated recovery in value occurs. If a decline in fair value is determined to be other-than-temporary, the cost basis of the individual security is written down to fair value which then becomes the security’s new cost basis. The new cost basis is not adjusted for subsequent recoveries in fair value.

Other-than-temporary impairment losses on equity securities are recognized in earnings. For debt securities, if the Company intends to sell an impaired security or it is more likely than not it will be required to sell a security prior to recovery of its amortized cost, an impairment loss is recognized in earnings for the entire difference between the amortized cost and fair value of the security on the measurement date. If the Company does not intend to sell the security or it is not more likely than not it will be required to sell the security prior to recovery of its amortized cost, the credit loss component of impairment is recognized in earnings. A credit loss is the difference between the amortized cost of the security and the present value of cash flows expected to be collected, discounted at the security’s effective interest rate at the date of acquisition. Impairment associated with factors other than credit, such as market liquidity, is recognized in other comprehensive income, net of tax.

Securities Deemed to be Other-Than-Temporarily Impaired

The Company recorded impairment losses in earnings on securities available-for-sale of $0.1 million for the three months ended March 31, 2015. There were no impairment losses recognized in earnings for the three months ended March 31, 2014. The Company recognized an after-tax amount of $0.1 million of non-credit-related other-than-temporary impairment in accumulated other comprehensive income or loss (“AOCI”) on securities classified as available-for-sale at March 31, 2015. There was no non-credit related other-than-temporary impairment recognized in AOCI on securities available-for-sale at March 31, 2014. No impairment losses were recognized in earnings or AOCI for securities held-to-maturity during the three months ended March 31, 2015 and 2014.

The following table summarizes the changes in cumulative credit-related other-than-temporary impairment recognized in earnings for debt securities for the three months ended March 31, 2015 and 2014. Credit-related other-than-temporary impairment that was recognized in earnings is reflected as an “Initial credit-related impairment” if the period reported is the first time the security had a credit impairment. A credit-related other-than-temporary impairment is reflected as a “Subsequent credit-related impairment” if the period reported is not the first time the security had a credit impairment. Cumulative impairment is reduced for securities with previously recognized credit-related impairment that were sold or redeemed during the period. Cumulative impairment is further adjusted for other changes in expected cash flows.

	For the three months ended
	March 31,
(in thousands)	2015		2014
Balance, beginning of period	$	2,470	$	4,549
Subsequent credit-related impairment	65		—
Balance, end of period	$	2,535	$	4,549

The following table provides a summary of the gross unrealized losses and fair value of investment securities that are not deemed to be other-than-temporarily impaired aggregated by investment category and length of time that the securities have been in a continuous unrealized loss position as of March 31, 2015 and December 31, 2014. The table also includes investment securities that had both a credit-related impairment recognized in earnings and a non-credit-related impairment recognized in AOCI.

	Less than 12 months				12 months or greater				Total
(in thousands)	Fair Value		Estimated Unrealized Loss		Fair Value		Estimated Unrealized Loss		Fair Value		Estimated Unrealized Loss
March 31, 2015
Securities available-for-sale:
U.S. Treasury	$	66,688	$	15	$	—	$	—	$	66,688	$	15
Federal agency - Debt	466,094		429		—		—		466,094		429
Federal agency - MBS	—		—		56,741		874		56,741		874
CMOs - Federal agency	549,307		1,652		1,195,370		20,301		1,744,677		21,953
CMOs - Non-agency	1,928		16		12,331		344		14,259		360
State and municipal	107,251		171		3,553		47		110,804		218
Other debt securities	12,609		3		—		—		12,609		3
Total debt securities	1,203,877		2,286		1,267,995		21,566		2,471,872		23,852
Equity securities and mutual funds	477		410		—		—		477		410
Total securities available-for-sale	$	1,204,354	$	2,696	$	1,267,995	$	21,566	$	2,472,349	$	24,262

Securities held-to-maturity:
Federal agency - Debt	$	—	$	—	$	5,950	$	72	$	5,950	$	72
Federal agency - MBS	34,532		81		40,762		486		75,294		567
CMOs - Federal agency	180,042		937		180,742		1,812		360,784		2,749
State and municipal	83,998		733		33,863		1,077		117,861		1,810
Total securities held-to-maturity	$	298,572	$	1,751	$	261,317	$	3,447	$	559,889	$	5,198

December 31, 2014
Securities available-for-sale:
U.S. Treasury	$	15,814	$	10	$	—	$	—	$	15,814	$	10
Federal agency - Debt	1,008,234		2,622		135,868		658		1,144,102		3,280
Federal agency - MBS	35		—		57,970		1,014		58,005		1,014
CMOs - Federal agency	871,026		3,417		1,261,695		35,452		2,132,721		38,869
CMOs - Non-agency	1,949		15		12,720		396		14,669		411
State and municipal	130,208		314		4,183		66		134,391		380
Total debt securities	2,027,266		6,378		1,472,436		37,586		3,499,702		43,964
Equity securities and mutual funds	538		350		—		—		538		350
Total securities available-for-sale	$	2,027,804	$	6,728	$	1,472,436	$	37,586	$	3,500,240	$	44,314

Securities held-to-maturity:
Federal agency - Debt	$	—	$	—	$	26,316	$	255	$	26,316	$	255
Federal agency - MBS	4,800		21		114,856		2,254		119,656		2,275
CMOs - Federal agency	202,014		2,247		588,019		8,045		790,033		10,292
State and municipal	14,851		76		95,647		1,921		110,498		1,997
Other debt securities	61,813		224		—		—		61,813		224
Total securities held-to-maturity	$	283,478	$	2,568	$	824,838	$	12,475	$	1,108,316	$	15,043

At March 31, 2015, the Company had securities available-for-sale with a fair value of $2.47 billion and securities held-to-maturity with a fair value of $559.9 million in an unrealized loss position. The debt securities in an unrealized loss position totaled 316 and included 2 U.S. Treasury notes, 12 federal agency debt securities, 17 federal agency MBS, 101 federal agency CMOs, 3 non-agency CMOs, 180 state and municipal securities and 1 other debt securities. At March 31, 2015, the Company had one equity security in an unrealized loss position.

At December 31, 2014, the Company had securities available-for-sale with a fair value of $3.50 billion and securities held-to-maturity with a fair value of $1.11 billion in an unrealized loss position. The debt securities in an unrealized loss position totaled 436 and included 2 U.S. Treasury notes, 37 federal agency debt securities, 23 federal agency MBS, 141 federal agency CMOs, 3 non-agency CMOs, 225 state and municipal securities and 5 other debt securities. At December 31, 2014, the Company had one equity security in an unrealized loss position.