Investment Securities (Tables)

3 Months Ended

Mar. 31, 2020

Investment Securities

Schedule of amortized cost and fair value of securities

	March 31, 2020								December 31, 2019
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
(dollars in thousands)	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
U.S. Treasury securities	$	30,483	$	444	$	—	$	30,927	$	29,832	$	56	$	—	$	29,888
Government-sponsored enterprises debt securities		26,705		16		—		26,721		101,697		19		(277)		101,439
Mortgage-backed securities:
Residential - Government agency		269,947		9,016		—		278,963		290,131		2,224		(1,146)		291,209
Residential - Government-sponsored enterprises		403,682		14,289		(304)		417,667		395,039		6,126		(1,673)		399,492
Commercial - Government-sponsored enterprises		184,635		3,345		(1,196)		186,784		101,798		555		(634)		101,719
Collateralized mortgage obligations:
Government agency		2,304,803		21,408		(5,333)		2,320,878		2,390,143		7,483		(16,348)		2,381,278
Government-sponsored enterprises		794,142		5,965		(3,590)		796,517		772,023		2,505		(3,909)		770,619
Total available-for-sale securities	$	4,014,397	$	54,483	$	(10,423)	$	4,058,457	$	4,080,663	$	18,968	$	(23,987)	$	4,075,644

Schedule of amortized cost and fair value of debt securities by contractual maturity

	March 31, 2020
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	—	$	—
Due after one year through five years		57,188		57,648
Due after five years through ten years		—		—
Due after ten years		—		—
		57,188		57,648
Mortgage-backed securities:
Residential - Government agency		269,947		278,963
Residential - Government-sponsored enterprises		403,682		417,667
Commercial - Government-sponsored enterprises		184,635		186,784
Total mortgage-backed securities		858,264		883,414
Collateralized mortgage obligations:
Government agency		2,304,803		2,320,878
Government-sponsored enterprises		794,142		796,517
Total collateralized mortgage obligations		3,098,945		3,117,395
Total available-for-sale securities	$	4,014,397	$	4,058,457

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

	Time in Continuous Loss as of March 31, 2020
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
Mortgage-backed securities:
Residential - Government-sponsored enterprises	$	(211)	$	95,144	$	(93)	$	10,191	$	(304)	$	105,335
Commercial - Government-sponsored enterprises		(1,196)		95,097		—		—		(1,196)		95,097
Collateralized mortgage obligations:
Government agency		(3,979)		480,482		(1,354)		94,077		(5,333)		574,559
Government-sponsored enterprises		(1,242)		144,625		(2,348)		149,246		(3,590)		293,871
Total available-for-sale securities with unrealized losses	$	(6,628)	$	815,348	$	(3,795)	$	253,514	$	(10,423)	$	1,068,862

	Time in Continuous Loss as of December 31, 2019
	Less Than 12 Months				12 Months or More				Total
	Unrealized				Unrealized				Unrealized
(dollars in thousands)	Losses		Fair Value		Losses		Fair Value		Losses		Fair Value
Government-sponsored enterprises debt securities	$	(277)	$	49,716	$	—	$	—	$	(277)	$	49,716
Mortgage-backed securities:
Residential - Government agency		—		—		(1,146)		109,614		(1,146)		109,614
Residential - Government-sponsored enterprises		(115)		76,481		(1,558)		109,025		(1,673)		185,506
Commercial - Government-sponsored enterprises		(634)		38,062		—		—		(634)		38,062
Collateralized mortgage obligations:
Government agency		(8,049)		969,762		(8,299)		565,764		(16,348)		1,535,526
Government-sponsored enterprises		(583)		180,785		(3,326)		209,752		(3,909)		390,537
Total available-for-sale securities with unrealized losses	$	(9,658)	$	1,314,806	$	(14,329)	$	994,155	$	(23,987)	$	2,308,961