Investment Securities

6 Months Ended

Jun. 30, 2011

Investments Securities [Abstract]

Investment Securities

3. Investment Securities

          The following tables provide the amortized cost and fair value for the major categories of held-to-maturity and available-for-sale securities. Held-to-maturity securities are carried at amortized cost, which reflects historical cost, adjusted for amortization of premiums and accretion of discounts. Available-for-sale securities are carried at fair value with net unrealized gains or losses reported on an after-tax basis as a component of other comprehensive income in shareholders’ equity.

	June 30, 2011
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
Securities available for sale
Debt Securities
U.S. government agency debentures		370,649		743		(148	)		371,244
U.S. States and political subdivisions		299,238		10,728		(181	)		309,785
Residential mortgage-backed securities:
U.S. government agencies		1,528,537		60,524		(90	)		1,588,971
Residential collateralized mortgage-backed securities:
U.S. government agencies		1,061,393		19,883		(1,326	)		1,079,950
Non-agency		93,733		114		—			93,847
Corporate debt securities		61,461		—		(10,738	)		50,723
Total debt securities		3,415,011		91,992		(12,483	)		3,494,520
Marketable equity securities		3,752		—		—			3,752
Total securities available for sale	$	3,418,763	$	91,992	$	(12,483	)	$	3,498,272
Securities held to maturity
Debt Securities
U.S. States and political subdivisions	$	80,857	$	—	$	—		$	80,857
Total securities held to maturity	$	80,857	$	—	$	—		$	80,857

	December 31, 2010
	Amortized		Gross Unrealized		Gross Unrealized			Fair
	Cost		Gains		Losses			Value
Securities available for sale
Debt Securities
U.S. government agency debentures	$	399,122	$	703	$	(194	)	$	399,631
U.S. States and political subdivisions		296,327		3,537		(2,119	)		297,745
Residential mortgage-backed securities:
U.S. government agencies		1,343,021		52,230		(547	)		1,394,704
Residential collateralized mortgage-backed securities:
U.S. government agencies		814,774		18,223		(2,306	)		830,691
Non-agency		15,018		—		—			15,018
Corporate debt securities		61,435		—		(16,106	)		45,329
Total debt securities		2,929,697		74,693		(21,272	)		2,983,118
Marketable equity securities		3,922		—		—			3,922
Total securities available for sale	$	2,933,619	$	74,693	$	(21,272	)	$	2,987,040
Securities held to maturity
Debt Securities
U.S. States and political subdivisions	$	59,962	$	—	$	—		$	59,962
Total securities held to maturity	$	59,962	$	—	$	—		$	59,962

	June 30, 2010
	Amortized		Gross Unrealized		Gross Unrealized			Fair
	Cost		Gains		Losses			Value
Securities available for sale
Debt Securities
U.S. Treasury	$	50,000	$	—	$	—		$	50,000
U.S. government agency debentures		326,338		1,130		(21	)		327,447
U.S. States and political subdivisions		286,297		7,960		(81	)		294,176
Residential mortgage-backed securities:
U.S. government agencies		1,491,498		72,850		(63	)		1,564,285
Residential collateralized mortgage-backed securities:
U.S. government agencies		761,197		23,543		—			784,740
Non-agency		20		—		(1	)		19
Corporate debt securities		61,410		—		(17,968	)		43,442
Total debt securities		2,976,760		105,483		(18,134	)		3,064,109
Marketable equity securities		3,443		—		—			3,443
Total securities available for sale	$	2,980,203	$	105,483	$	(18,134	)	$	3,067,552
Securities held to maturity
Debt Securities
U.S. States and political subdivisions	$	65,160	$	—	$	—		$	65,160
Total securities held to maturity	$	65,160	$	—	$	—		$	65,160

          Federal Reserve Bank (“FRB”) and Federal Home Loan Bank (“FHLB”) stock constitute the majority of other investments on the consolidated balance sheet.

	June 30,		December 31,		June 30,
	2011		2010		2010
FRB stock	$	20,804	$	20,725	$	19,787
FHLB stock		139,398		139,398		139,398
Other		603		629		1,037
Total other investments	$	160,805	$	160,752	$	160,222

          FRB and FHLB stock is classified as a restricted investment, carried at cost and valued based on the ultimate recoverability of par value. Cash and stock dividends received on the stock are reported as interest income. There are no identified events or changes in circumstances that may have a significant adverse effect on these investments carried at cost.

          At June 30, 2011, securities totaling $2.0 billion were pledged to secure trust and public deposits and securities sold under agreements to repurchase and for other purposes required or permitted by law.

Gross Unrealized Losses and Fair Value

          The following table presents the gross unrealized losses and fair value of securities in the securities available-for-sale portfolio by length of time that individual securities in each category had been in a continuous loss position.

	June 30, 2011
	Less than 12 months							12 months or longer							Total
						Number of							Number of
						Impaired							Impaired
	Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses
Debt Securities
U.S. government agency debentures	$	23,538	$	(148	)		2	$	—	$	—			—	$	23,538	$	(148	)
U.S. States and political subdivisions		18,176		(158	)		24		655		(23	)		1		18,831		(181	)
Residential mortgage-backed securities:
U.S. government agencies		14,229		(87	)		1		182		(3	)		2		14,411		(90	)
Residential collateralized mortgage-backed securities:
U.S. government agencies		265,319		(1,326	)		18		—		—			—		265,319		(1,326	)
Corporate debt securities		—		—			—		50,723		(10,738	)		8		50,723		(10,738	)
Total temporarily impaired securities	$	321,262	$	(1,719	)		45	$	51,560	$	(10,764	)		11	$	372,822	$	(12,483	)

	December 31, 2010
	Less than 12 months							12 months or longer							Total
						Number of							Number of
						Impaired							Impaired
	Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses
Debt Securities
U.S. government agency debentures	$	109,238	$	(194	)		8	$	—	$	—			—	$	109,238	$	(194	)
U.S. States and political subdivisions		105,530		(2,095	)		164		665		(24	)		1		106,195		(2,119	)
Residential mortgage-backed securities:
U.S. government agencies		67,474		(544	)		7		195		(3	)		1		67,669		(547	)
Residential collateralized mortgage-backed securities:
U.S. government agencies		188,264		(2,306	)		17		—		—			—		188,264		(2,306	)
Non-agency		—		—			—		—		—			—		—		—
Corporate debt securities		—		—			—		45,329		(16,106	)		8		45,329		(16,106	)
Total temporarily impaired securities	$	470,506	$	(5,139	)		196	$	46,189	$	(16,133	)		10	$	516,695	$	(21,272	)

	June 30, 2010
	Less than 12 months							12 months or longer							Total
						Number of							Number of
						Impaired							Impaired
	Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses			Securities		Fair Value		Unrealized Losses
Debt Securities
U.S. government agency debentures	$	30,275	$	(21	)		2	$	—	$	—			—	$	30,275	$	(21	)
U.S. States and political subdivisions		13,822		(68	)		20		689		(13	)		1		14,511		(81	)
Residential mortgage-backed securities:
U.S. government agencies		15,016		(60	)		2		227		(3	)		1		15,243		(63	)
Residential collateralized mortgage-backed securities:
Non-agency		3		(1	)		1		—		—			—		3		(1	)
Corporate debt securities		—		—			—		43,442		(17,968	)		8		43,442		(17,968	)
Total temporarily impaired securities	$	59,116	$	(150	)		25	$	44,358	$	(17,984	)		10	$	103,474	$	(18,134	)

          At least quarterly the Corporation conducts a comprehensive security-level impairment assessment on all securities in an unrealized loss position to determine if other-than-temporary impairment (“OTTI”) exists. An unrealized loss exists when the current fair value of an individual security is less than its amortized cost basis. Under the current OTTI accounting model for debt securities, an OTTI loss must be recognized for a debt security in an unrealized loss position if the Corporation intends to sell the security or it is more likely than not that the Corporation will be required to sell the security before recovery of its amortized cost basis. In this situation, the amount of loss recognized in income is equal to the difference between the fair value and the amortized cost basis of the security. Even if the Corporation does not expect to sell the security, the Corporation must evaluate the expected cash flows to be received to determine if a credit loss has occurred. In the event of a credit loss, only the amount of impairment associated with the credit loss is recognized in income. The portion of the unrealized loss relating to other factors, such as liquidity conditions in the market or changes in market interest rates, is recorded in other comprehensive income. Equity securities are also evaluated to determine whether the unrealized loss is expected to be recoverable based on whether evidence exists to support a realizable value equal to or greater than the amortized cost basis. If it is probable that the Corporation will not recover the amortized cost basis, taking into consideration the estimated recovery period and its ability to hold the equity security until recovery, OTTI is recognized.

          The security-level assessment is performed on each security, regardless of the classification of the security as available for sale or held to maturity. The assessments are based on the nature of the securities, the financial condition of the issuer, the extent and duration of the securities, the extent and duration of the loss and whether Management intends to sell or it is more likely than not that it will be required to sell a security before recovery of its amortized cost basis, which may be maturity. For those securities for which the assessment shows the Corporation will recover the entire cost basis, Management does not intend to sell these securities and it is not more likely than not that the Corporation will be required to sell them before the anticipated recovery of the amortized cost basis, the gross unrealized losses are recognized in other comprehensive income, net of tax.

          As of June 30, 2011, gross unrealized losses are concentrated within corporate debt securities which is composed of eight, single issuer, trust preferred securities with stated maturities. Such investments are less than 2% of the fair value of the entire investment portfolio. None of the corporate issuers have deferred paying dividends on their issued trust preferred shares in which the Corporation is invested. The fair values of these investments have been impacted by market conditions which have caused risk premiums to increase markedly, resulting in the significant decline in the fair value of the trust preferred securities. Management believes the Corporation will fully recover the cost of these securities and it does not intend to sell these securities and it is not more likely than not that it will be required to sell them before the anticipated recovery of the remaining amortized cost basis, which may be maturity. As a result, Management concluded that these securities were not OTTI at June 30, 2011 and has recognized the total amount of the impairment in other comprehensive income, net of tax.

Realized Gains and Losses

          The following table shows the proceeds from sales of available-for-sale- securities and the gross unrealized gains and losses on the sales of those securities that have been included in earnings as a result of those sales. Gains or losses on the sales of available-for-sale securities are recognized upon sale and are determined using the specific identification method.

	Quarter ended						Six months ended
	June 30,						June 30,
	2011			2010			2011			2010
Proceeds	$	32,900		$	487,905		$	32,900		$	500,006
Realized gains	$	945		$	1,602		$	945		$	1,602
Realized losses		(56	)		(951	)		(56	)		(951	)
Net securities gains	$	889		$	651		$	889		$	651

Contractual Maturity of Debt Securities

          The following table shows the remaining contractual maturities and contractual yields of debt securities held-to-maturity and available-for-sale as of June 30, 2011. Estimated lives on mortgage-backed securities may differ from contractual maturities as issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

										Residential			Residential
							Residential			collateralized			collateralized
				U.S. States and			mortgage-backed			mortgage			mortgage
	U.S. Government			political			securities - U.S			obligations - U.S.			obligations - non -
	agency			subdivisions			govt. agency			govt. agency			U.S. govt. agency			Corporate debt						Weighted
	debentures			obligations			obligations			obligations			issued			securities			Total			Average Yield
Securities Available for Sale
Remaining maturity:
One year or less	$	259,805		$	10,313		$	4,067		$	34,945		$	—		$	—		$	309,130			1.35	%
Over one year through five years		111,439			21,351			1,479,708			1,045,005			17,643			—			2,675,146			2.92	%
Over five years through ten years		—			137,952			105,196			—			76,204			—			319,352			3.34	%
Over ten years		—			140,169			—			—			—			50,723			190,892			4.55	%
Fair Value	$	371,244		$	309,785		$	1,588,971		$	1,079,950		$	93,847		$	50,723		$	3,494,520			2.92	%
Amortized Cost	$	370,649		$	299,238		$	1,528,537		$	1,061,393		$	93,733		$	61,461		$	3,415,011
Weighted-Average Yield		0.74	%		5.69	%		3.45	%		2.43	%		0.62	%		0.99	%		2.92	%
Weighted-Average Maturity		0.7			9.1			3.3			2.8			5.9			16.3			3.7
Securities Held to Maturity
Remaining maturity:
One year or less	$	—		$	27,770		$	—		$	—		$	—		$	—		$	27,770			3.79	%
Over one year through five years		—			14,507			—			—			—			—			14,507			3.79	%
Over five years through ten years		—			3,780			—			—			—			—			3,780			3.79	%
Over ten years		—			34,800			—			—			—			—			34,800			7.29	%
Fair Value	$	—		$	80,857		$	—		$	—		$	—		$	—		$	80,857			5.30	%
Amortized Cost	$	—		$	80,857		$	—		$	—		$	—		$	—		$	80,857
Weighted-Average Yield					5.30	%														5.30	%
Weighted-Average Maturity					7.4															7.4