Investment Securities (Tables)

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Investment securities available for sale

June 30, 2015:	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	($ in Thousands)
Investment securities available for sale:
U.S. Treasury securities	$	999	$	2	$	—		$	1,001
Obligations of state and political subdivisions ("municipal securities")	451,577		18,576		(50		)	470,103
Residential mortgage-related securities:
FNMA / FHLMC	2,207,339		52,006		(7,718		)	2,251,627
GNMA	905,728		1,876		(5,520		)	902,084
Private-label	1,926		1		(10		)	1,917
GNMA commercial mortgage-related securities	1,794,286		3,803		(23,527		)	1,774,562
Other securities (debt and equity)	6,638		66		—			6,704
Total investment securities available for sale	$	5,368,493	$	76,330	$	(36,825	)	$	5,407,998
Investment securities held to maturity:
Municipal securities	$	532,382	$	4,360	$	(6,288	)	$	530,454
Total investment securities held to maturity	$	532,382	$	4,360	$	(6,288	)	$	530,454
December 31, 2014:	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	($ in Thousands)
Investment securities available for sale:
U.S. Treasury securities	$	999	$	—	$	(1	)	$	998
Municipal securities	560,839		21,869		(29		)	582,679
Residential mortgage-related securities:
FNMA / FHLMC	3,534,240		59,640		(30,423		)	3,563,457
GNMA	165,863		1,596		(127		)	167,332
Private-label	2,297		7		(10		)	2,294
GNMA commercial mortgage-related securities	1,097,913		1,922		(25,942		)	1,073,893
Other securities (debt and equity)	6,108		51		—			6,159
Total investment securities available for sale	$	5,368,259	$	85,085	$	(56,532	)	$	5,396,812
Investment securities held to maturity:
Municipal securities	$	404,455	$	9,444	$	(832	)	$	413,067
Total investment securities held to maturity	$	404,455	$	9,444	$	(832	)	$	413,067

Investment securities held to maturity

June 30, 2015:	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	($ in Thousands)
Investment securities available for sale:
U.S. Treasury securities	$	999	$	2	$	—		$	1,001
Obligations of state and political subdivisions ("municipal securities")	451,577		18,576		(50		)	470,103
Residential mortgage-related securities:
FNMA / FHLMC	2,207,339		52,006		(7,718		)	2,251,627
GNMA	905,728		1,876		(5,520		)	902,084
Private-label	1,926		1		(10		)	1,917
GNMA commercial mortgage-related securities	1,794,286		3,803		(23,527		)	1,774,562
Other securities (debt and equity)	6,638		66		—			6,704
Total investment securities available for sale	$	5,368,493	$	76,330	$	(36,825	)	$	5,407,998
Investment securities held to maturity:
Municipal securities	$	532,382	$	4,360	$	(6,288	)	$	530,454
Total investment securities held to maturity	$	532,382	$	4,360	$	(6,288	)	$	530,454
December 31, 2014:	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
	($ in Thousands)
Investment securities available for sale:
U.S. Treasury securities	$	999	$	—	$	(1	)	$	998
Municipal securities	560,839		21,869		(29		)	582,679
Residential mortgage-related securities:
FNMA / FHLMC	3,534,240		59,640		(30,423		)	3,563,457
GNMA	165,863		1,596		(127		)	167,332
Private-label	2,297		7		(10		)	2,294
GNMA commercial mortgage-related securities	1,097,913		1,922		(25,942		)	1,073,893
Other securities (debt and equity)	6,108		51		—			6,159
Total investment securities available for sale	$	5,368,259	$	85,085	$	(56,532	)	$	5,396,812
Investment securities held to maturity:
Municipal securities	$	404,455	$	9,444	$	(832	)	$	413,067
Total investment securities held to maturity	$	404,455	$	9,444	$	(832	)	$	413,067

Amortized cost and fair values of investment securities available for sale and held to maturity by contractual maturity

	Available for Sale					Held to Maturity
($ in Thousands)	Amortized Cost		Fair Value			Amortized Cost		Fair Value
Due in one year or less	$	23,394	$	23,632		$	—	$	—
Due after one year through five years	245,147		256,811			2,481		2,513
Due after five years through ten years	190,071		196,705			127,117		127,465
Due after ten years	584		604			402,784		400,476
Total debt securities	459,196		477,752			532,382		530,454
Residential mortgage-related securities:
FNMA / FHLMC	2,207,339		2,251,627			—		—
GNMA	905,728		902,084
Private-label	1,926		1,917			—		—
GSE commercial mortgage-related securities	1,794,286		1,774,562			—		—
Equity securities	18		56			—		—
Total investment securities	$	5,368,493	$	5,407,998		$	532,382	$	530,454
Ratio of Fair Value to Amortized Cost			100.7		%			99.6		%

Schedule of Realized Gain (Loss)

	Six Months Ended June 30,						Year Ended December 31,
	2015			2014			2014
				($ in Thousands)
Gross gains	$	5,251		$	1,102		$	1,184
Gross losses	(4,009		)	(690		)	(690		)
Investment securities gains, net	$	1,242		$	412		$	494
Proceeds from sales of investment securities	$	1,065,328		$	80,362		$	102,011

Unrealized losses and fair value of available for sale and held to maturity securities, by investment category and time length

	Less than 12 months						12 months or more						Total
June 30, 2015	Number of Securities	Unrealized Losses			Fair Value		Number of Securities	Unrealized Losses			Fair Value		Unrealized Losses			Fair Value
		($ in Thousands)
Investment securities available for sale:
Municipal securities	18	$	(47	)	$	8,022	1	$	(3	)	$	186	$	(50	)	$	8,208
Residential mortgage-related securities:
GSE	62	(6,719		)	1,015,136		20	(6,519		)	387,416		(13,238		)	1,402,552
Private-label	2	(9		)	1,825		2	(1		)	21		(10		)	1,846
GSE commercial mortgage-related securities	29	(5,043		)	858,144		20	(18,484		)	446,382		(23,527		)	1,304,526
Total		$	(11,818	)	$	1,883,127		$	(25,007	)	$	834,005	$	(36,825	)	$	2,717,132
Investment securities held to maturity:
Municipal securities	623	$	(5,824	)	$	303,766	21	$	(464	)	$	9,346	$	(6,288	)	$	313,112
Total		$	(5,824	)	$	303,766		$	(464	)	$	9,346	$	(6,288	)	$	313,112

For comparative purposes, the following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2014.

	Less than 12 months						12 months or more						Total
December 31, 2014	Number of Securities	Unrealized Losses			Fair Value		Number of Securities	Unrealized Losses			Fair Value		Unrealized Losses			Fair Value
		($ in Thousands)
Investment securities available for sale:
U.S. Treasury securities	1	$	(1	)	$	998	—	$	—		$	—	$	(1	)	$	998
Municipal securities	6	(9		)	3,374		6	(20		)	2,133		(29		)	5,507
Residential mortgage-related securities:
GSE	16	(1,404		)	333,713		56	(29,146		)	1,256,533		(30,550		)	1,590,246
Private-label	1	(9		)	1,772		2	(1		)	27		(10		)	1,799
GSE commercial mortgage-related securities	9	(1,766		)	329,982		20	(24,176		)	460,425		(25,942		)	790,407
Total		$	(3,189	)	$	669,839		$	(53,343	)	$	1,719,118	$	(56,532	)	$	2,388,957
Investment securities held to maturity:
Municipal securities	74	$	(216	)	$	31,924	85	$	(616	)	$	38,915	$	(832	)	$	70,839
Total		$	(216	)	$	31,924		$	(616	)	$	38,915	$	(832	)	$	70,839