Securities (Tables)

3 Months Ended

Mar. 31, 2013

Securities Available for Sale

This table provides detailed information about securities available for sale at March 31, 2013 and December 31, 2012 (in thousands):

March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	121,777	$	1,260	$	(216	)	$	122,821
U.S. Agencies		1,042,955		6,136		(119	)		1,048,972
Mortgage-backed		3,218,547		57,084		(4,913	)		3,270,718
State and political subdivisions		1,928,957		45,193		(4,214	)		1,969,936
Corporates		427,500		2,378		(741	)		429,137
Commercial Paper		—		—		—			—
Total	$	6,739,736	$	112,051	$	(10,203	)	$	6,841,584
December 31, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	116,856	$	1,166	$	(171	)	$	117,851
U.S. Agencies		1,019,640		6,597		(122	)		1,026,115
Mortgage-backed		3,480,006		78,600		(2,413	)		3,556,193
State and political subdivisions		1,842,715		51,341		(1,372	)		1,892,684
Corporates		337,706		1,945		(764	)		338,887
Commercial Paper		5,733		—		—			5,733
Total	$	6,802,656	$	139,649	$	(4,842	)	$	6,937,463

Securities Held to Maturity

The table below provides detailed information for securities held to maturity at March 31, 2013 and December 31, 2012 (in thousands):

March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
State and political subdivisions	$	129,498	$	13,033	$	—	$	142,531
December 31, 2012
State and political subdivisions	$	114,756	$	14,739	$	—	$	129,495

Available for Sale Investments' Gross Unrealized Losses and Fair Value, Aggregated by Investment Category and Length of Time that Individual Securities have been in Continuous Unrealized Loss Position

The following table shows the Company’s available for sale investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2013 and December 31, 2012 (in thousands).

March 31, 2013	Less than 12 months					12 months or more					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury	$	19,765	$	(216	)	$	—	$	—		$	19,765	$	(216	)
U.S. Agencies		195,815		(119	)		—		—			195,815		(119	)
Mortgage-backed		583,894		(4,913	)		—		—			583,894		(4,913	)
State and political subdivisions		289,738		(4,160	)		5,540		(54	)		295,278		(4,214	)
Corporates		153,982		(741	)		—		—			153,982		(741	)
Commercial Paper		—		—			—		—			—		—
Total temporarily-impaired debt securities available for sale	$	1,243,194	$	(10,149	)	$	5,540	$	(54	)	$	1,248,734	$	(10,203	)

December 31, 2012	Less than 12 months					12 months or more					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury	$	29,747	$	(171	)	$	—	$	—		$	29,747	$	(171	)
U.S. Agencies		295,747		(122	)		—		—			295,747		(122	)
Mortgage-backed		398,384		(2,413	)		—		—			398,384		(2,413	)
State and political subdivisions		132,951		(1,358	)		2,604		(14	)		135,555		(1,372	)
Corporates		178,564		(764	)		—		—			178,564		(764	)
Commercial Paper		5,733		—			—		—			5,733		—
Total temporarily-impaired debt securities available for sale	$	1,041,126	$	(4,828	)	$	2,604	$	(14	)	$	1,043,730	$	(4,842	)

Available-for-sale Securities [Member]

Contractual Maturity Information

The following table presents contractual maturity information for securities available for sale at March 31, 2013 (in thousands):

	Amortized Cost		Fair Value
Due in 1 year or less	$	569,017	$	571,721
Due after 1 year through 5 years		2,020,200		2,048,453
Due after 5 years through 10 years		753,872		773,932
Due after 10 years		178,100		176,760
Total		3,521,189		3,570,866
Mortgage-backed securities		3,218,547		3,270,718
Total securities available for sale	$	6,739,736	$	6,841,584

Held-to-maturity Securities [Member]

Contractual Maturity Information

The following table presents contractual maturity information for securities held to maturity at March 31, 2013 (in thousands):

	Amortized Cost		Fair Value
Due in 1 year or less	$	1,466	$	1,614
Due after 1 year through 5 years		30,829		33,932
Due after 5 years through 10 years		31,884		35,092
Due after 10 years		65,319		71,893
Total securities held to maturity	$	129,498	$	142,531