Investment Securities (Tables)

6 Months Ended

Jun. 30, 2016

Investment Securities

Schedule of amortized cost and fair value of securities

	June 30, 2016								December 31, 2015
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury securities	$	—	$	—	$	—	$	—	$	502,126	$	—	$	(2,150)	$	499,976
Non-government securities		159,141		267		—		159,408		96,132		16		(324)		95,824
Government agency mortgage-backed securities		191,016		1,162		—		192,178		56,490		—		(508)		55,982
Government-sponsored enterprises mortgage-backed securities		8,993		522		—		9,515		10,185		560		—		10,745
Non-government mortgage-backed securities		—		—		—		—		—		157		—		157
Non-government asset-backed securities		36,105		—		(16)		36,089		95,453		—		(143)		95,310
Collateralized mortgage obligations:
Government agency		3,104,344		33,115		(3,158)		3,134,301		2,261,526		1,984		(23,576)		2,239,934
Government-sponsored enterprises		1,066,382		8,762		(5,368)		1,069,776		1,046,854		724		(18,241)		1,029,337
Total available-for-sale securities	$	4,565,981	$	43,828	$	(8,542)	$	4,601,267	$	4,068,766	$	3,441	$	(44,942)	$	4,027,265

Schedule of unrealized gross losses and fair values of securities in a continuous loss position

	Time in Continuous Loss as of June 30, 2016
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
Non-government asset-backed securities	$	(13)		30,996	$	(3)	$	5,093	$	(16)	$	36,089
Collateralized mortgage obligations:
Government agency		(460)		137,915		(2,698)		246,933		(3,158)		384,848
Government-sponsored enterprises		(18)		37,357		(5,350)		332,101		(5,368)		369,458
Total available-for-sale securities with unrealized losses	$	(491)	$	206,268	$	(8,051)	$	584,127	$	(8,542)	$	790,395

	Time in Continuous Loss as of December 31, 2015
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
U.S. Treasury securities	$	(2,150)	$	499,976	$	—	$	—	$	(2,150)	$	499,976
Non-government securities		(324)		70,808		—		—		(324)		70,808
Government agency mortgage-backed securities		(508)		55,982		—		—		(508)		55,982
Non-government asset-backed securities		(143)		95,310		—		—		(143)		95,310
Collateralized mortgage obligations:
Government agency		(11,423)		1,428,423		(12,153)		354,335		(23,576)		1,782,758
Government-sponsored enterprises		(3,132)		532,122		(15,109)		354,987		(18,241)		887,109
Total available-for-sale securities with unrealized losses	$	(17,680)	$	2,682,621	$	(27,262)	$	709,322	$	(44,942)	$	3,391,943

Schedule of amortized cost and fair value of non-government securities, by contractual maturity, and of mortgage-and asset-backed securities

	June 30, 2016
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	21,141	$	21,150
Due after one year through five years		50,000		50,067
Due after five years through ten years		88,000		88,191
		159,141		159,408
Government agency mortgage-backed securities		191,016		192,178
Government-sponsored enterprises mortgage-backed securities		8,993		9,515
Non-government asset-backed securities		36,105		36,089
Collateralized mortgage obligations:
Government agency		3,104,344		3,134,301
Government-sponsored enterprises		1,066,382		1,069,776
Total mortgage- and asset-backed securities		4,406,840		4,441,859
Total available-for-sale securities	$	4,565,981	$	4,601,267