Investment Securities (Tables)

9 Months Ended

Sep. 30, 2020

Investment Securities

Schedule of amortized cost and fair value of securities

	September 30, 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 and government agency debt securities	$	142,368	$	2,589	$	(1)	$	144,956	$	29,832	$	56	$	—	$	29,888
Government-sponsored enterprises debt securities		—		—		—		—		101,697		19		(277)		101,439
Mortgage-backed securities:
Residential - Government agency		188,797		5,151		—		193,948		290,131		2,224		(1,146)		291,209
Residential - Government-sponsored enterprises		417,286		14,706		(150)		431,842		395,039		6,126		(1,673)		399,492
Commercial - Government agency		737,891		16,875		(2,844)		751,922		—		—		—		—
Commercial - Government-sponsored enterprises		486,814		11,481		(22)		498,273		101,798		555		(634)		101,719
Collateralized mortgage obligations:
Government agency		2,047,556		38,722		(302)		2,085,976		2,390,143		7,483		(16,348)		2,381,278
Government-sponsored enterprises		1,563,844		22,181		(59)		1,585,966		772,023		2,505		(3,909)		770,619
Total available-for-sale securities	$	5,584,556	$	111,705	$	(3,378)	$	5,692,883	$	4,080,663	$	18,968	$	(23,987)	$	4,075,644

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

	September 30, 2020
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	—	$	—
Due after one year through five years		38,268		38,863
Due after five years through ten years		3,277		3,280
Due after ten years		100,823		102,813
		142,368		144,956
Mortgage-backed securities:
Residential - Government agency		188,797		193,948
Residential - Government-sponsored enterprises		417,286		431,842
Commercial - Government agency		737,891		751,922
Commercial - Government-sponsored enterprises		486,814		498,273
Total mortgage-backed securities		1,830,788		1,875,985
Collateralized mortgage obligations:
Government agency		2,047,556		2,085,976
Government-sponsored enterprises		1,563,844		1,585,966
Total collateralized mortgage obligations		3,611,400		3,671,942
Total available-for-sale securities	$	5,584,556	$	5,692,883

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

	Time in Continuous Loss as of September 30, 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
U.S. Treasury and government agency debt securities	$	(1)	$	4,976	$	—	$	—	$	(1)	$	4,976
Mortgage-backed securities:
Residential - Government-sponsored enterprises		(150)		51,125		—		—		(150)		51,125
Commercial - Government agency		(2,844)		188,392		—		—		(2,844)		188,392
Commercial - Government-sponsored enterprises		(22)		70,587		—		—		(22)		70,587
Collateralized mortgage obligations:
Government agency		(275)		101,340		(27)		7,475		(302)		108,815
Government-sponsored enterprises		(57)		52,077		(2)		8,100		(59)		60,177
Total available-for-sale securities with unrealized losses	$	(3,349)	$	468,497	$	(29)	$	15,575	$	(3,378)	$	484,072

	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