Investment Securities (Tables)

3 Months Ended

Mar. 31, 2021

Investment Securities

Schedule of amortized cost and fair value of securities

	March 31, 2021								December 31, 2020
	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	$	177,745	$	447	$	(2,468)	$	175,724	$	170,123	$	1,359	$	(61)	$	171,421
Mortgage-backed securities:
Residential - Government agency		129,908		3,986		—		133,894		155,169		5,293		—		160,462
Residential - Government-sponsored enterprises		797,426		10,867		(7,373)		800,920		434,282		13,643		(725)		447,200
Commercial - Government agency		523,293		8,068		(3,845)		527,516		583,232		16,537		(119)		599,650
Commercial - Government-sponsored enterprises		1,180,034		1,676		(47,535)		1,134,175		931,095		9,045		(7,983)		932,157
Collateralized mortgage obligations:
Government agency		1,818,181		29,899		(2,982)		1,845,098		1,902,326		32,246		(1,019)		1,933,553
Government-sponsored enterprises		2,081,844		15,537		(22,229)		2,075,152		1,808,804		18,991		(823)		1,826,972
Total available-for-sale securities	$	6,708,431	$	70,480	$	(86,432)	$	6,692,479	$	5,985,031	$	97,114	$	(10,730)	$	6,071,415

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

	March 31, 2021
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	—	$	—
Due after one year through five years		41,513		41,878
Due after five years through ten years		83,988		83,461
Due after ten years		52,244		50,385
		177,745		175,724
Mortgage-backed securities:
Residential - Government agency		129,908		133,894
Residential - Government-sponsored enterprises		797,426		800,920
Commercial - Government agency		523,293		527,516
Commercial - Government-sponsored enterprises		1,180,034		1,134,175
Total mortgage-backed securities		2,630,661		2,596,505
Collateralized mortgage obligations:
Government agency		1,818,181		1,845,098
Government-sponsored enterprises		2,081,844		2,075,152
Total collateralized mortgage obligations		3,900,025		3,920,250
Total available-for-sale securities	$	6,708,431	$	6,692,479

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

	Time in Continuous Loss as of March 31, 2021
	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	$	(2,468)	$	121,457	$	—	$	—	$	(2,468)	$	121,457
Mortgage-backed securities:
Residential - Government-sponsored enterprises		(7,373)		511,463		—		—		(7,373)		511,463
Commercial - Government agency		(3,845)		248,776		—		—		(3,845)		248,776
Commercial - Government-sponsored enterprises		(47,535)		898,725		—		—		(47,535)		898,725
Collateralized mortgage obligations:
Government agency		(2,974)		370,875		(8)		5,020		(2,982)		375,895
Government-sponsored enterprises		(22,229)		1,036,086		—		—		(22,229)		1,036,086
Total available-for-sale securities with unrealized losses	$	(86,424)	$	3,187,382	$	(8)	$	5,020	$	(86,432)	$	3,192,402

	Time in Continuous Loss as of December 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
U.S. Treasury and government agency debt securities	$	(61)	$	38,507	$	—	$	—	$	(61)	$	38,507
Mortgage-backed securities:
Residential - Government-sponsored enterprises		(725)		64,987		—		—		(725)		64,987
Commercial - Government agency		(119)		32,346		—		—		(119)		32,346
Commercial - Government-sponsored enterprises		(7,983)		427,759		—		—		(7,983)		427,759
Collateralized mortgage obligations:
Government agency		(994)		209,124		(25)		6,190		(1,019)		215,314
Government-sponsored enterprises		(823)		296,160		—		—		(823)		296,160
Total available-for-sale securities with unrealized losses	$	(10,705)	$	1,068,883	$	(25)	$	6,190	$	(10,730)	$	1,075,073