Investment Securities (Tables)

9 Months Ended

Sep. 30, 2013

Investments Debt And Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Investment Securities

The amortized cost and estimated fair value of investment securities were as follows:

	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
	(in thousands)
September 30, 2013
Investment securities available for sale:
U.S. Treasury and federal agencies	$	37,432		480		25	$	37,887
Obligations of states and political subdivisions		17,614		355		6		17,963
Mortgage-backed securities:
Government issued or guaranteed		4,214,895		116,758		1,254		4,330,399
Privately issued		2,789		1,032		5		3,816
Collateralized debt obligations		42,686		17,724		1,107		59,303
Other debt securities		137,661		1,758		20,015		119,404
Equity securities		102,032		22,221		845		123,408
		4,555,109		160,328		23,257		4,692,180
Investment securities held to maturity:
Obligations of states and political subdivisions		170,370		4,279		88		174,561
Mortgage-backed securities:
Government issued or guaranteed		2,914,687		39,987		29,015		2,925,659
Privately issued		224,767		—		56,891		167,876
Other debt securities		9,290		—		—		9,290
		3,319,114		44,266		85,994		3,277,386
Other securities		298,479		—		—		298,479
Total	$	8,172,702		204,594		109,251	$	8,268,045
December 31, 2012
Investment securities available for sale:
U.S. Treasury and federal agencies	$	38,422		922		—	$	39,344
Obligations of states and political subdivisions		20,375		534		8		20,901
Mortgage-backed securities:
Government issued or guaranteed		3,163,210		208,060		229		3,371,041
Privately issued		1,142,287		7,272		125,673		1,023,886
Collateralized debt obligations		43,228		19,663		1,022		61,869
Other debt securities		136,603		2,247		26,900		111,950
Equity securities		98,945		14,921		3,420		110,446
		4,643,070		253,619		157,252		4,739,437
Investment securities held to maturity:
Obligations of states and political subdivisions		182,103		7,647		27		189,723
Mortgage-backed securities:
Government issued or guaranteed		597,340		31,727		—		629,067
Privately issued		242,378		160		94,900		147,638
Other debt securities		10,455		—		—		10,455
		1,032,276		39,534		94,927		976,883
Other securities		302,648		—		—		302,648
Total	$	5,977,994		293,153		252,179	$	6,018,968

Changes in Credit Losses Associated with Debt Securities for Which OTTI Losses

Changes in credit losses associated with debt securities for which OTTI losses have been recognized in earnings for the three months and nine months ended September 30, 2013 and 2012 follows:

	Three months ended September 30
	2013			2012
	(in thousands)
Beginning balance	$	794			264,197
Additions for credit losses not previously recognized		—			5,672
Reductions for realized losses		(626	)		(67,926	)
Ending balance	$	168			201,943

	Nine months ended September 30
	2013			2012
	(in thousands)
Beginning balance	$	197,809			285,399
Additions for credit losses not previously recognized		9,800			33,331
Reductions for realized losses		(207,441	)		(116,787	)
Ending balance	$	168			201,943

Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity

At September 30, 2013, the amortized cost and estimated fair value of debt securities by contractual maturity were as follows:

	Amortized cost		Estimated fair value
	(in thousands)
Debt securities available for sale:
Due in one year or less	$	24,886		24,971
Due after one year through five years		21,212		22,016
Due after five years through ten years		8,282		8,553
Due after ten years		181,013		179,017
		235,393		234,557
Mortgage-backed securities available for sale		4,217,684		4,334,215
	$	4,453,077		4,568,772
Debt securities held to maturity:
Due in one year or less	$	18,617		18,751
Due after one year through five years		65,392		67,400
Due after five years through ten years		86,361		88,410
Due after ten years		9,290		9,290
		179,660		183,851
Mortgage-backed securities held to maturity		3,139,454		3,093,535
	$	3,319,114		3,277,386

Investment Securities in Continuous Unrealized Loss Position

A summary of investment securities that as of September 30, 2013 and December 31, 2012 had been in a continuous unrealized loss position for less than twelve months and those that had been in a continuous unrealized loss position for twelve months or longer follows:

	Less than 12 months					12 months or more
	Fair value		Unrealized losses			Fair value		Unrealized losses
	(in thousands)
September 30, 2013
Investment securities available for sale:
U.S. Treasury and federal agencies	$	6,346		(25	)		—		—
Obligations of states and political subdivisions		577		(2	)		559		(4	)
Mortgage-backed securities:
Government issued or guaranteed		174,503		(1,126	)		5,731		(128	)
Privately issued		—		—			107		(5	)
Collateralized debt obligations		—		—			5,995		(1,107	)
Other debt securities		1,576		(7	)		102,898		(20,008	)
Equity securities		2,777		(845	)		—		—
		185,779		(2,005	)		115,290		(21,252	)
Investment securities held to maturity:
Obligations of states and political subdivisions		14,751		(70	)		1,558		(18	)
Mortgage-backed securities:
Government issued or guaranteed		1,259,353		(29,015	)		—		—
Privately issued		—		—			167,876		(56,891	)
		1,274,104		(29,085	)		169,434		(56,909	)
Total	$	1,459,883		(31,090	)		284,724		(78,161	)

	Less than 12 months					12 months or more
	Fair value		Unrealized losses			Fair value		Unrealized losses
	(in thousands)
December 31, 2012
Investment securities available for sale:
Obligations of states and political subdivisions	$	166		(1	)		683		(7	)
Mortgage-backed securities:
Government issued or guaranteed		12,107		(65	)		8,804		(164	)
Privately issued		121,487		(692	)		774,328		(124,981	)
Collateralized debt obligations		—		—			6,043		(1,022	)
Other debt securities		—		—			95,685		(26,900	)
Equity securities		5,535		(1,295	)		2,956		(2,125	)
		139,295		(2,053	)		888,499		(155,199	)
Investment securities held to maturity:
Obligations of states and political subdivisions		1,026		(5	)		3,558		(22	)
Privately issued mortgage-backed securities		—		—			147,273		(94,900	)
		1,026		(5	)		150,831		(94,922	)
Total	$	140,321		(2,058	)		1,039,330		(250,121	)