SECURITIES

Securities are classified as held-to-maturity, trading, or available-for-sale at the time of purchase. Securities classified as held-to-maturity are securities for which management has the intent and ability to hold to maturity and are stated at cost.

The Company's trading securities consist of diversified investment securities reported at fair value that are held in a grantor trust under deferred compensation arrangements in which plan participants may direct amounts earned to be invested in securities other than Company stock.

All other securities are classified as available-for-sale and are carried at fair value with unrealized gains and losses, net of related deferred income taxes, recorded in stockholders' equity as a separate component of accumulated other comprehensive loss.

A summary of the Company's securities portfolio by category and maturity is presented in the following tables.

Securities Portfolio

(Dollar amounts in thousands)



	As of June 30, 2016									As of December 31, 2015
	Amortized Cost		Gross Unrealized					Fair Value		Amortized Cost		Gross Unrealized					Fair Value
	Amortized Cost		Gains		Losses			Fair Value		Amortized Cost		Gains		Losses			Fair Value
Securities Available-for-Sale
U.S. treasury securities	$	38,548	$	341	$	—		$	38,889	$	17,000	$	15	$	(35	)	$	16,980
U.S. agency securities	196,735		2,580		(84		)	199,231		86,461		351		(169		)	86,643
Collateralized mortgage obligations ("CMOs")	908,550		13,239		(1,054		)	920,735		695,198		1,072		(9,085		)	687,185
Other mortgage-backed securities ("MBSs")	281,924		4,839		(106		)	286,657		152,481		1,920		(871		)	153,530
Municipal securities	286,547		8,046		(29		)	294,564		321,437		6,443		(310		)	327,570
Trust-preferred collateralized debt obligations ("CDOs")	48,219		32		(17,820		)	30,431		48,287		34		(16,792		)	31,529
Equity securities	3,290		83		(121		)	3,252		3,282		86		(169		)	3,199
Total securities available-for-sale	$	1,763,813	$	29,160	$	(19,214	)	$	1,773,759	$	1,324,146	$	9,921	$	(27,431	)	$	1,306,636
Securities Held-to-Maturity
Municipal securities	$	20,672	$	—	$	(2,278	)	$	18,394	$	23,152	$	—	$	(3,098	)	$	20,054
Trading Securities								$	17,693								$	16,894

Remaining Contractual Maturity of Securities

(Dollar amounts in thousands)



	As of June 30, 2016
	Available-for-Sale				Held-to-Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	84,587	$	83,558	$	3,220	$	2,865
After one year to five years	430,910		425,669		7,840		6,976
After five years to ten years	6,333		6,256		2,111		1,878
After ten years	48,219		47,632		7,501		6,675
Securities that do not have a single contractual maturity date	1,193,764		1,210,644		—		—
Total	$	1,763,813	$	1,773,759	$	20,672	$	18,394

The carrying value of securities available-for-sale that were pledged to secure deposits or for other purposes as permitted or required by law totaled $1.1 billion at June 30, 2016 and $856.9 million at December 31, 2015. No securities held-to-maturity were pledged as of June 30, 2016 or December 31, 2015.

Purchases and sales of securities are recognized on a trade date basis. Realized securities gains or losses are reported in net securities gains in the Condensed Consolidated Statements of Income. The cost of securities sold is based on the specific identification method. During the quarters and six months ended June 30, 2016 and 2015 there were no material gross trading gains (losses). The following table presents net realized gains on securities available-for-sale for the quarters and six months ended June 30, 2016 and 2015.

Securities Available-for-Sale Gains

(Dollar amounts in thousands)



	Quarters Ended June 30,					Six Months Ended June 30,
	2016			2015		2016			2015
Gains on sales of securities:
Gross realized gains	$	149		$	515	$	1,079		$	1,165
Gross realized losses	(126		)	—		(169		)	(138		)
Net realized gains on sales of securities	23			515		910			1,027
Non-cash impairment charges:
Other-than-temporary securities impairment ("OTTI")	—			—		—			—
Net realized gains	$	23		$	515	$	910		$	1,027

Accounting guidance requires that the credit portion of an OTTI charge be recognized through income. If a decline in fair value below carrying value is not attributable to credit deterioration and the Company does not intend to sell the security or believe it would not be more likely than not required to sell the security prior to recovery, the Company records the non-credit related portion of the decline in fair value in other comprehensive income.

The following table presents a rollforward of life-to-date OTTI recognized in earnings related to all securities available-for-sale held by the Company for the quarters and six months ended June 30, 2016 and 2015. The majority of the beginning and ending balance of OTTI relates to CDOs currently held by the Company.

Changes in OTTI Recognized in Earnings

(Dollar amounts in thousands)



	Quarters Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Beginning balance	$	23,709	$	23,709	$	23,709	$	23,880
OTTI included in earnings ⁽¹⁾:
Reduction for sales of securities ⁽²⁾	—		—		—		(171		)
Ending balance	$	23,709	$	23,709	$	23,709	$	23,709


⁽¹⁾	Included in net securities gains in the Condensed Consolidated Statements of Income.


⁽²⁾	This reduction was driven by the sale of one CMO with a carrying value of $1.3 million during the six months ended June 30, 2015.

The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of June 30, 2016 and December 31, 2015.

Securities in an Unrealized Loss Position

(Dollar amounts in thousands)



		Less Than 12 Months				12 Months or Longer				Total
	Number of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
As of June 30, 2016
Securities Available-for-Sale
U.S. agency securities	8	$	17,500	$	84	$	—	$	—	$	17,500	$	84
CMOs	31	24,763		113		89,507		941		114,270		1,054
MBSs	10	18,479		79		6,965		27		25,444		106
Municipal securities	10	3,171		18		1,012		11		4,183		29
CDOs	10	1,750		96		28,058		17,724		29,808		17,820
Equity securities	2	485		120		2,377		1		2,862		121
Total	71	$	66,148	$	510	$	127,919	$	18,704	$	194,067	$	19,214
Securities Held-To-Maturity
Municipal securities	16	$	18,394	$	2,278	$	—	$	—	$	18,394	$	2,278
As of December 31, 2015
Securities Available-for-Sale
U.S. treasury securities	4	$	7,946	$	35	$	—	$	—	$	7,946	$	35
U.S. agency securities	10	30,620		169		—		—		30,620		169
CMOs	133	309,787		3,110		257,362		5,975		567,149		9,085
MBSs	27	63,028		427		31,980		444		95,008		871
Municipal securities	68	8,135		65		24,227		245		32,362		310
CDOs	8	8,034		971		21,642		15,821		29,676		16,792
Equity securities	2	485		120		2,305		49		2,790		169
Total	252	$	428,035	$	4,897	$	337,516	$	22,534	$	765,551	$	27,431
Securities Held-To-Maturity
Municipal securities	19	$	20,054	$	3,098	$	—	$	—	$	20,054	$	3,098

Substantially all of the Company's CMOs and other MBSs are either backed by U.S. government-owned agencies or issued by U.S. government-sponsored enterprises. Municipal securities are issued by municipal authorities, and the majority are supported by third party insurance or some other form of credit enhancement. Management does not believe any of these securities with unrealized losses as of June 30, 2016 represent OTTI related to credit deterioration. These unrealized losses are attributed to changes in interest rates and temporary market movements. The Company does not intend to sell these securities and it is not more likely than not that the Company will be required to sell them before recovery of their amortized cost basis, which may be at maturity.

The unrealized losses on CDOs as of June 30, 2016 reflect changes in market activity for these securities. Management does not believe these unrealized losses represent OTTI related to credit deterioration. In addition, the Company does not intend to sell the CDOs with unrealized losses and the Company does not believe it is more likely than not that it will be required to sell them before recovery of their amortized cost basis, which may be at maturity. Significant judgment is required to calculate the fair value of the CDOs, all of which are pooled. For a detailed discussion of the CDO valuation methodology, see Note 13, "Fair Value."