Investment Securities (Tables)

9 Months Ended

Sep. 30, 2014

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost and Fair Values of Investment Securities

The following table presents the amortized cost and estimated fair values of investment securities, which were all classified as available for sale:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
September 30, 2014
Equity securities	$	34,380	$	10,927	$	(29	)	$	45,278
U.S. Government securities	200		—		—			200
U.S. Government sponsored agency securities	235		5		—			240
State and municipal securities	250,195		7,917		(496		)	257,616
Corporate debt securities	99,670		5,777		(4,020		)	101,427
Collateralized mortgage obligations	975,971		6,700		(27,631		)	955,040
Mortgage-backed securities	954,412		14,201		(6,278		)	962,335
Auction rate securities	158,725		1		(10,253		)	148,473
	$	2,473,788	$	45,528	$	(48,707	)	$	2,470,609

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in thousands)
December 31, 2013
Equity securities	$	33,922	$	12,355	$	(76	)	$	46,201
U.S. Government securities	525		—		—			525
U.S. Government sponsored agency securities	720		7		(1		)	726
State and municipal securities	281,810		6,483		(3,444		)	284,849
Corporate debt securities	100,468		5,685		(7,404		)	98,749
Collateralized mortgage obligations	1,069,138		8,036		(44,776		)	1,032,398
Mortgage-backed securities	949,328		13,881		(17,497		)	945,712
Auction rate securities	172,299		234		(13,259		)	159,274
	$	2,608,210	$	46,681	$	(86,457	)	$	2,568,434

Schedule of Amortized Cost and Fair Values of Debt Securities by Contractual Maturities

The amortized cost and estimated fair values of debt securities as of September 30, 2014, by contractual maturity, are shown in the following table. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in one year or less		$	13,218	$	13,284
Due from one year to five years		75,307		78,967
Due from five years to ten years		187,966		193,537
Due after ten years		232,534		222,168
		509,025		507,956
Collateralized mortgage obligations		975,971		955,040
Mortgage-backed securities		954,412		962,335
		$	2,439,408	$	2,425,331

Summary of Gains and Losses from Equity and Debt Securities, and Losses Recognized from Other-than-Temporary Impairment

The following table presents information related to the gross realized gains and losses on the sales of equity and debt securities:

	Gross Realized Gains		Gross Realized Losses			Other-than- temporary Impairment Losses			Net Gains (Losses)
Three months ended September 30, 2014	(in thousands)
Equity securities	$	99	$	—		$	—		$	99
Debt securities	—		—			(18		)	(18		)
Total	$	99	$	—		$	(18	)	$	81
Three months ended September 30, 2013
Equity securities	$	2,135	$	—		$	—		$	2,135
Debt securities	617		(22		)	(97		)	498
Total	$	2,752	$	(22	)	$	(97	)	$	2,633
Nine months ended September 30, 2014
Equity securities	$	100	$	—		$	(12	)	$	88
Debt securities	1,446		(323		)	(18		)	1,105
Total	$	1,546	$	(323	)	$	(30	)	$	1,193
Nine months ended September 30, 2013
Equity securities	$	4,357	$	(28	)	$	(27	)	$	4,302
Debt securities	3,788		(22		)	(97		)	3,669
Total	$	8,145	$	(50	)	$	(124	)	$	7,971

Summary Of Other Than Temporary Impairment Charges Recorded In Statement Of Operations [Table Text Block]

The following table presents a summary of the cumulative credit related other-than-temporary impairment charges, recognized as components of earnings, for debt securities held by the Corporation at September 30, 2014 and 2013:

	Three months ended September 30						Nine months ended September 30
	2014			2013			2014			2013
	(in thousands)
Balance of cumulative credit losses on debt securities, beginning of period	$	(17,214	)	$	(20,607	)	$	(20,691	)	$	(23,079	)
Additions for credit losses recorded which were not previously recognized as components of earnings	(18		)	(97		)	(18		)	(97		)
Reductions for securities sold during the period	—			—			3,472			2,468
Reductions for increases in cash flows expected to be collected that are recognized over the remaining life of the security	—			—			5			4
Balance of cumulative credit losses on debt securities, end of period	$	(17,232	)	$	(20,704	)	$	(17,232	)	$	(20,704	)

Gross Unrealized Losses and Fair Values of Investments by Category and Length of Time in Continuous Unrealized Loss Position

The following table presents the gross unrealized losses and estimated fair values of investments, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at September 30, 2014:

	Less than 12 months					12 months or longer					Total
	Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses			Estimated Fair Value		Unrealized Losses
	(in thousands)
State and municipal securities	$	7,996	$	(37	)	$	26,484	$	(459	)	$	34,480	$	(496	)
Corporate debt securities	—		—			38,900		(4,020		)	38,900		(4,020		)
Collateralized mortgage obligations	53,189		(248		)	652,396		(27,383		)	705,585		(27,631		)
Mortgage-backed securities	241,707		(527		)	291,712		(5,751		)	533,419		(6,278		)
Auction rate securities	—		—			148,380		(10,253		)	148,380		(10,253		)
Total debt securities	302,892		(812		)	1,157,872		(47,866		)	1,460,764		(48,678		)
Equity securities	269		(17		)	77		(12		)	346		(29		)
	$	303,161	$	(829	)	$	1,157,949	$	(47,878	)	$	1,461,110	$	(48,707	)

Summary of Amortized Cost and Fair Values of Corporate Debt Securities

The following table presents the amortized cost and estimated fair value of corporate debt securities:

	September 30, 2014				December 31, 2013
	Amortized cost		Estimated fair value		Amortized cost		Estimated fair value
	(in thousands)
Single-issuer trust preferred securities	$	47,546	$	44,075	$	47,481	$	40,531
Subordinated debt	47,498		50,289		47,405		50,327
Pooled trust preferred securities	2,050		4,487		2,997		5,306
Corporate debt securities issued by financial institutions	97,094		98,851		97,883		96,164
Other corporate debt securities	2,576		2,576		2,585		2,585
Available for sale corporate debt securities	$	99,670	$	101,427	$	100,468	$	98,749