Available-For-Sale Securities

3 Months Ended

Mar. 31, 2013

Available-for-sale Securities [Abstract]

Available-For-Sale Securities

Available-For-Sale Securities

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

	March 31, 2013
(Dollars in thousands)	Amortized Cost		Gross unrealized gains		Gross unrealized losses			Fair Value
U.S. Treasury	$	220,215	$	190	$	(2,760	)	$	217,645
U.S. Government agencies	975,386		2,960		(4,631		)	973,715
Municipal	107,947		2,628		(316		)	110,259
Corporate notes and other:
Financial issuers	136,761		2,569		(2,280		)	137,050
Other	11,628		195		—			11,823
Mortgage-backed: (1)
Mortgage-backed securities	294,728		7,360		(3,194		)	298,894
Collateralized mortgage obligations	68,496		897		(5		)	69,388
Other equity securities	52,413		745		(1,101		)	52,057
Total available-for-sale securities	$	1,867,574	$	17,544	$	(14,287	)	$	1,870,831

	December 31, 2012
	Amortized Cost		Gross unrealized gains		Gross unrealized losses			Fair Value
(Dollars in thousands)
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

	March 31, 2012
	Amortized Cost		Gross unrealized gains		Gross unrealized losses			Fair Value
(Dollars in thousands)
U.S. Treasury	$	23,063	$	128	$	(2	)	$	23,189
U.S. Government agencies	682,847		4,082		(4,149		)	682,780
Municipal	67,970		1,963		(18		)	69,915
Corporate notes and other:
Financial issuers	148,492		2,569		(9,044		)	142,017
Other	26,475		329		(5		)	26,799
Mortgage-backed: (1)
Mortgage-backed securities	846,380		11,866		(806		)	857,440
Collateralized mortgage obligations	28,423		286		(1		)	28,708
Other equity securities	42,664		111		(4,279		)	38,496
Total available-for-sale securities	$	1,866,314	$	21,334	$	(18,304	)	$	1,869,344

(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 March 31, 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	$	197,422	$	(2,760	)	$	—	$	—		$	197,422	$	(2,760	)
U.S. Government agencies	510,371		(4,629		)	6,032		(2		)	516,403		(4,631		)
Municipal	19,977		(314		)	463		(2		)	20,440		(316		)
Corporate notes and other:
Financial issuers	4,606		(37		)	73,696		(2,243		)	78,302		(2,280		)
Other	—		—			—		—			—		—
Mortgage-backed:
Mortgage-backed securities	158,142		(3,194		)	—		—			158,142		(3,194		)
Collateralized mortgage obligations	13,616		(5		)	—		—			13,616		(5		)
Other equity securities	5,920		(80		)	24,379		(1,021		)	30,299		(1,101		)
Total	$	910,054	$	(11,019	)	$	104,570	$	(3,268	)	$	1,014,624	$	(14,287	)

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 March 31, 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 and auction rate securities included in other equity securities. The corporate securities of financial issuers in this category were comprised of seven fixed-to-floating rate bonds and three trust-preferred securities, all of which continue to be considered investment grade. 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 March 31,
(Dollars in thousands)	2013			2012
Realized gains	$	313		$	828
Realized losses	(62		)	(12		)
Net realized gains	$	251		$	816
Other than temporary impairment charges	—			—
Gains on available-for-sale securities, net	$	251		$	816
Proceeds from sales of available-for-sale securities	$	41,056		$	737,369

The amortized cost and fair value of securities as of March 31, 2013, December 31, 2012 and March 31, 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:

	March 31, 2013				December 31, 2012				March 31, 2012
(Dollars in thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	247,388	$	247,836	$	188,594	$	189,015	$	79,980	$	80,351
Due in one to five years	337,431		338,633		419,588		419,654		496,724		494,391
Due in five to ten years	357,677		356,871		361,037		362,135		106,545		105,856
Due after ten years	509,441		507,152		501,177		503,999		265,598		264,102
Mortgage-backed	363,224		368,282		261,871		271,574		874,803		886,148
Other equity securities	52,413		52,057		52,846		49,699		42,664		38,496
Total available-for-sale securities	$	1,867,574	$	1,870,831	$	1,785,113	$	1,796,076	$	1,866,314	$	1,869,344

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