Investment Securities (Tables)

3 Months Ended

Mar. 31, 2013

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:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Held to Maturity at March 31, 2013	(in thousands)
Mortgage-backed securities	$	257	$	22	$	—		$	279
Available for Sale at March 31, 2013
Equity securities	$	117,624	$	6,507	$	(241	)	$	123,890
U.S. Government securities	325		—		—			325
U.S. Government sponsored agency securities	885		10		(1		)	894
State and municipal securities	283,142		12,221		(170		)	295,193
Corporate debt securities	112,221		8,906		(6,083		)	115,044
Collateralized mortgage obligations	1,293,745		15,279		(3,225		)	1,305,799
Mortgage-backed securities	789,048		27,022		(7		)	816,063
Auction rate securities	173,966		—		(19,327		)	154,639
	$	2,770,956	$	69,945	$	(29,054	)	$	2,811,847

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Held to Maturity at December 31, 2012	(in thousands)
Mortgage-backed securities	$	292	$	27	$	—		$	319
Available for Sale at December 31, 2012
Equity securities	$	118,465	$	5,016	$	(918	)	$	122,563
U.S. Government securities	325		—		—			325
U.S. Government sponsored agency securities	2,376		21		—			2,397
State and municipal securities	301,842		13,763		(86		)	315,519
Corporate debt securities	112,162		7,858		(7,178		)	112,842
Collateralized mortgage obligations	1,195,234		16,008		(123		)	1,211,119
Mortgage-backed securities	847,790		31,831		—			879,621
Auction rate securities	174,026		—		(24,687		)	149,339
	$	2,752,220	$	74,497	$	(32,992	)	$	2,793,725

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 March 31, 2013, 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.

	Held to Maturity				Available for Sale
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in one year or less	$	—	$	—	$	36,715	$	36,777
Due from one year to five years	—		—		64,996		69,357
Due from five years to ten years	—		—		179,933		190,269
Due after ten years	—		—		288,895		269,692
	—		—		570,539		566,095
Collateralized mortgage obligations	—		—		1,293,745		1,305,799
Mortgage-backed securities	257		279		789,048		816,063
	$	257	$	279	$	2,653,332	$	2,687,957

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

There were no gross realized losses on the sales of investment securities or other-than-temporary impairment losses recognized for investment securities during the three months ended March 31, 2013 and 2012. The following table presents information related to the gross realized gains on the sales of equity and debt securities (in thousands):

Three months ended March 31, 2013
Equity securities	$	1,139
Debt securities	1,334
Total	$	2,473
Three months ended March 31, 2012
Equity securities	$	1,086
Debt securities	165
Total	$	1,251

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 March 31, 2013:

	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)
U.S. Government sponsored agency securities	$	—	$	—		$	80	$	(1	)	$	80	$	(1	)
State and municipal securities	15,203		(170		)	—		—			15,203		(170		)
Corporate debt securities	2,992		(4		)	44,513		(6,079		)	47,505		(6,083		)
Collateralized mortgage obligations	457,415		(3,225		)	—		—			457,415		(3,225		)
Mortgage-backed securities	25,033		(7		)	—		—			25,033		(7		)
Auction rate securities	10,954		(502		)	143,596		(18,825		)	154,550		(19,327		)
Total debt securities	511,597		(3,908		)	188,189		(24,905		)	699,786		(28,813		)
Equity securities	1,077		(60		)	1,618		(181		)	2,695		(241		)
	$	512,674	$	(3,968	)	$	189,807	$	(25,086	)	$	702,481	$	(29,054	)

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:

	March 31, 2013				December 31, 2012
	Amortized cost		Estimated fair value		Amortized cost		Estimated fair value
	(in thousands)
Single-issuer trust preferred securities	$	56,863	$	52,523	$	56,834	$	51,656
Subordinated debt	47,315		51,652		47,286		51,747
Pooled trust preferred securities	5,530		8,356		5,530		6,927
Corporate debt securities issued by financial institutions	109,708		112,531		109,650		110,330
Other corporate debt securities	2,513		2,513		2,512		2,512
Available for sale corporate debt securities	$	112,221	$	115,044	$	112,162	$	112,842