Investment Securities, Available-for-Sale

6 Months Ended

Jun. 30, 2013

Investments, Debt and Equity Securities [Abstract]

Investment Securities, Available-for-Sale

Note 2. Investment Securities, Available-for-Sale

A comparison of the amortized cost and estimated fair value of the Company’s investment securities designated as available-for-sale is presented below.

	June 30, 2013
	Weighted		Amortized		Gross Unrealized			Fair
(Dollars in thousands)	Yield		Cost		Gains	Losses		Value
U.S. government sponsored enterprises
Maturing after one year through five years	2.27	%	$	12,840	270	—		13,110
Maturing after five years through ten years	1.71	%	40		1	—		41
	2.27	%	12,880		271	—		13,151
State and local governments
Maturing within one year	2.02	%	5,066		41	—		5,107
Maturing after one year through five years	2.07	%	158,331		3,063	(265	)	161,129
Maturing after five years through ten years	3.11	%	55,026		904	(656	)	55,274
Maturing after ten years	4.53	%	1,089,519		44,313	(15,466	)	1,118,366
	4.17	%	1,307,942		48,321	(16,387	)	1,339,876
Corporate bonds
Maturing within one year	2.06	%	64,391		630	—		65,021
Maturing after one year through five years	2.10	%	357,036		2,571	(3,173	)	356,434
Maturing after five years through ten years	2.27	%	21,635		53	(346	)	21,342
	2.10	%	443,062		3,254	(3,519	)	442,797
Residential mortgage-backed securities	2.18	%	1,917,954		13,728	(6,129	)	1,925,553
Total investment securities	2.88	%	$	3,681,838	65,574	(26,035	)	3,721,377

	December 31, 2012
	Weighted		Amortized		Gross Unrealized			Fair
(Dollars in thousands)	Yield		Cost		Gains	Losses		Value
U.S. government and federal agency
Maturing within one year	1.62	%	$	201	1	—		202
U.S. government sponsored enterprises
Maturing after one year through five years	2.30	%	17,064		371	—		17,435
Maturing after five years through ten years	2.03	%	44		1	—		45
	2.29	%	17,108		372	—		17,480
State and local governments
Maturing within one year	2.01	%	4,288		28	(2	)	4,314
Maturing after one year through five years	2.11	%	149,497		4,142	(142	)	153,497
Maturing after five years through ten years	2.95	%	38,346		1,102	(99	)	39,349
Maturing after ten years	4.70	%	935,897		82,823	(1,362	)	1,017,358
	4.29	%	1,128,028		88,095	(1,605	)	1,214,518
Corporate bonds
Maturing within one year	1.73	%	18,412		51	—		18,463
Maturing after one year through five years	2.22	%	250,027		4,018	(238	)	253,807
Maturing after five years through ten years	2.23	%	16,144		381	—		16,525
	2.19	%	284,583		4,450	(238	)	288,795
Collateralized debt obligations
Maturing after ten years	8.03	%	1,708		—	—		1,708
Residential mortgage-backed securities	1.95	%	2,156,049		8,860	(4,607	)	2,160,302
Total investment securities	2.71	%	$	3,587,677	101,778	(6,450	)	3,683,005

Included in the residential mortgage-backed securities are $39,375,000 and $46,733,000 as of June 30, 2013 and December 31, 2012, respectively, of non-guaranteed private label whole loan mortgage-backed securities of which none of the underlying collateral is considered “subprime.”

Maturities of securities do not reflect repricing opportunities present in adjustable rate securities, nor do they reflect expected shorter maturities based upon early prepayment of principal. Weighted average yields are based on the level-yield method taking into account premium amortization, discount accretion and mortgage-backed securities’ prepayment provisions. Weighted average yields on tax-exempt investment securities exclude the federal income tax benefit.

The cost of each investment sold is determined by specific identification. Gain or loss on sale of investments consists of the following: 

	Three Months ended				Six Months ended
(Dollars in thousands)	June 30, 2013			June 30, 2012	June 30, 2013			June 30, 2012
Gross proceeds	$	75,649		—	$	79,488		—
Less amortized cost	(75,408		)	—	(79,384		)	—
Net gain on sale of investments	$	241		—	$	104		—
Gross gain on sale of investments	$	256		—	$	256		—
Gross loss on sale of investments	(15		)	—	(152		)	—
Net gain on sale of investments	$	241		—	$	104		—

Investments with an unrealized loss position are summarized as follows:

	June 30, 2013
	Less than 12 Months				12 Months or More			Total
(Dollars in thousands)	Fair Value		Unrealized Loss		Fair Value	Unrealized Loss		Fair Value	Unrealized Loss
State and local governments	$	312,576	(15,987	)	10,434	(400	)	323,010	(16,387	)
Corporate bonds	211,592		(3,519	)	—	—		211,592	(3,519	)
Residential mortgage-backed securities	511,542		(6,086	)	15,991	(43	)	527,533	(6,129	)
Total temporarily impaired securities	$	1,035,710	(25,592	)	26,425	(443	)	1,062,135	(26,035	)

	December 31, 2012
	Less than 12 Months				12 Months or More			Total
(Dollars in thousands)	Fair Value		Unrealized Loss		Fair Value	Unrealized Loss		Fair Value	Unrealized Loss
State and local governments	$	102,896	(1,531	)	4,533	(74	)	107,429	(1,605	)
Corporate bonds	41,856		(238	)	—	—		41,856	(238	)
Residential mortgage-backed securities	955,235		(4,041	)	62,905	(566	)	1,018,140	(4,607	)
Total temporarily impaired securities	$	1,099,987	(5,810	)	67,438	(640	)	1,167,425	(6,450	)

With respect to the Company’s review of its securities in an unrealized loss position at June 30, 2013, management determined that it did not intend to sell and there was no expected requirement to sell any of its temporarily impaired securities. Based on an analysis of its impaired securities as of June 30, 2013 and December 31, 2012, the Company determined that none of such securities had other-than-temporary impairment.