Available-For-Sale Securities

The following tables are a summary of the available-for-sale securities portfolio as of the dates shown:



	September 30, 2013
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	225,190	$	150	$	(14,438	)	$	210,902
U.S. Government agencies	954,050		2,213		(43,574		)	912,689
Municipal	152,010		1,983		(3,346		)	150,647
Corporate notes and other:
Financial issuers	132,320		2,252		(2,513		)	132,059
Other	7,011		126		(15		)	7,122
Mortgage-backed: ⁽¹⁾
Mortgage-backed securities	268,166		4,157		(12,861		)	259,462
Collateralized mortgage obligations	60,001		458		(728		)	59,731
Other equity securities	53,837		1,097		(5,663		)	49,271
Total available-for-sale securities	$	1,852,585	$	12,436	$	(83,138	)	$	1,781,883



	December 31, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	220,226	$	198	$	(937	)	$	219,487
U.S. Government agencies	986,186		4,839		(986		)	990,039
Municipal	107,868		2,899		(296		)	110,471
Corporate notes and other:
Financial issuers	142,205		2,452		(3,982		)	140,675
Other	13,911		220		—			14,131
Mortgage-backed: ⁽¹⁾
Mortgage-backed securities	188,485		8,805		(30		)	197,260
Collateralized mortgage obligations	73,386		928		—			74,314
Other equity securities	52,846		215		(3,362		)	49,699
Total available-for-sale securities	$	1,785,113	$	20,556	$	(9,593	)	$	1,796,076



	September 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	25,045	$	211	$	—		$	25,256
U.S. Government agencies	626,725		3,833		(2,374		)	628,184
Municipal	96,696		2,711		(23		)	99,384
Corporate notes and other:
Financial issuers	142,158		2,550		(5,170		)	139,538
Other	17,200		251		—			17,451
Mortgage-backed: ⁽¹⁾
Mortgage-backed securities	225,393		13,733		—			239,126
Collateralized mortgage obligations	66,422		690		—			67,112
Other equity securities	43,737		216		(3,236		)	40,717
Total available-for-sale securities	$	1,243,376	$	24,195	$	(10,803	)	$	1,256,768


(1)	Consisting entirely of residential mortgage-backed securities, none of which are subprime.

The following table presents the portion of the Company’s available-for-sale securities portfolio which has gross unrealized losses, reflecting the length of time that individual securities have been in a continuous unrealized loss position at September 30, 2013:



	Continuous unrealized losses existing for less than 12 months					Continuous unrealized losses existing for greater than 12 months					Total
(Dollars in thousands)	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury	$	185,734	$	(14,438	)	$	—	$	—		$	185,734	$	(14,438	)
U.S. Government agencies	413,113		(37,142		)	60,240		(6,432		)	473,353		(43,574		)
Municipal	78,209		(3,342		)	696		(4		)	78,905		(3,346		)
Corporate notes and other:
Financial issuers	16,530		(232		)	63,661		(2,281		)	80,191		(2,513		)
Other	985		(15		)	—		—			985		(15		)
Mortgage-backed:
Mortgage-backed securities	175,261		(12,861		)	—		—			175,261		(12,861		)
Collateralized mortgage obligations	33,511		(728		)	—		—			33,511		(728		)
Other equity securities	14,507		(614		)	20,350		(5,049		)	34,857		(5,663		)
Total	$	917,850	$	(69,372	)	$	144,947	$	(13,766	)	$	1,062,797	$	(83,138	)

The Company conducts a regular assessment of its investment securities to determine whether securities are other-than-temporarily impaired considering, among other factors, the nature of the securities, credit ratings or financial condition of the issuer, the extent and duration of the unrealized loss, expected cash flows, market conditions and the Company’s ability to hold the securities through the anticipated recovery period.

The Company does not consider securities with unrealized losses at September 30, 2013 to be other-than-temporarily impaired. The Company does not intend to sell these investments and it is more likely than not that the Company will not be required to sell these investments before recovery of the amortized cost bases, which may be the maturity dates of the securities. The unrealized losses within each category have occurred as a result of changes in interest rates, market spreads and market conditions subsequent to purchase. Securities with continuous unrealized losses existing for more than twelve months were primarily corporate securities of financial issuers, agency bonds and auction rate securities included in other equity securities. The corporate securities of financial issuers in this category were comprised primarily of investment grade securities including six fixed-to-floating rate bonds and three trust-preferred securities. Additionally, a review of the issuers indicated that they all have strong capital ratios.

The following table provides information as to the amount of gross gains and gross losses realized and proceeds received through the sales of available-for-sale investment securities:



	Three months ended September 30,						Nine months ended September 30,
(Dollars in thousands)	2013			2012			2013			2012
Realized gains	$	118		$	413		$	434		$	2,350
Realized losses	(43		)	(4		)	(106		)	(16		)
Net realized gains	$	75		$	409		$	328		$	2,334
Other than temporary impairment charges	—			—			—			—
Gains on available-for-sale securities, net	$	75		$	409		$	328		$	2,334
Proceeds from sales of available-for-sale securities	$	45,078		$	694,608		$	129,537		$	2,059,154

The amortized cost and fair value of securities as of September 30, 2013, December 31, 2012 and September 30, 2012, by contractual maturity, are shown in the following table. Contractual maturities may differ from actual maturities as borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Mortgage-backed securities are not included in the maturity categories in the following maturity summary as actual maturities may differ from contractual maturities because the underlying mortgages may be called or prepaid without penalties:



	September 30, 2013				December 31, 2012				September 30, 2012
(Dollars in thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	285,746	$	286,066	$	188,594	$	189,015	$	83,658	$	83,863
Due in one to five years	316,076		316,474		419,588		419,654		471,863		471,747
Due in five to ten years	344,742		328,895		361,037		362,135		135,580		137,116
Due after ten years	524,017		481,984		501,177		503,999		216,723		217,087
Mortgage-backed	328,167		319,193		261,871		271,574		291,815		306,238
Other equity securities	53,837		49,271		52,846		49,699		43,737		40,717
Total available-for-sale securities	$	1,852,585	$	1,781,883	$	1,785,113	$	1,796,076	$	1,243,376	$	1,256,768

Securities having a carrying value of $1.2 billion at September 30, 2013 and $1.1 billion at both December 31, 2012 and September 30, 2012, were pledged as collateral for public deposits, trust deposits, FHLB advances, securities sold under repurchase agreements and derivatives. At September 30, 2013, there were no securities of a single issuer, other than U.S. Government-sponsored agency securities, which exceeded 10% of shareholders’ equity.