Investment Securities (Tables)

6 Months Ended

Jun. 30, 2021

Investment Securities

Schedule of amortized cost and fair value of securities

	June 30, 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	$	182,354	$	545	$	(2,127)	$	180,772	$	170,123	$	1,359	$	(61)	$	171,421
Mortgage-backed securities:
Residential - Government agency		110,115		3,174		—		113,289		155,169		5,293		—		160,462
Residential - Government-sponsored enterprises		1,257,032		10,776		(4,360)		1,263,448		434,282		13,643		(725)		447,200
Commercial - Government agency		487,607		6,956		(3,116)		491,447		583,232		16,537		(119)		599,650
Commercial - Government-sponsored enterprises		1,244,031		7,116		(27,342)		1,223,805		931,095		9,045		(7,983)		932,157
Collateralized mortgage obligations:
Government agency		1,645,170		22,631		(5,667)		1,662,134		1,902,326		32,246		(1,019)		1,933,553
Government-sponsored enterprises		2,024,844		11,195		(17,004)		2,019,035		1,808,804		18,991		(823)		1,826,972
Total available-for-sale securities	$	6,951,153	$	62,393	$	(59,616)	$	6,953,930	$	5,985,031	$	97,114	$	(10,730)	$	6,071,415

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

	June 30, 2021
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	—	$	—
Due after one year through five years		41,497		41,787
Due after five years through ten years		83,608		82,670
Due after ten years		57,249		56,315
		182,354		180,772
Mortgage-backed securities:
Residential - Government agency		110,115		113,289
Residential - Government-sponsored enterprises		1,257,032		1,263,448
Commercial - Government agency		487,607		491,447
Commercial - Government-sponsored enterprises		1,244,031		1,223,805
Total mortgage-backed securities		3,098,785		3,091,989
Collateralized mortgage obligations:
Government agency		1,645,170		1,662,134
Government-sponsored enterprises		2,024,844		2,019,035
Total collateralized mortgage obligations		3,670,014		3,681,169
Total available-for-sale securities	$	6,951,153	$	6,953,930

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

	Time in Continuous Loss as of June 30, 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	$	(2,127)	$	120,987	$	—	$	—	$	(2,127)	$	120,987
Mortgage-backed securities:
Residential - Government-sponsored enterprises		(4,360)		618,414		—		—		(4,360)		618,414
Commercial - Government agency		(2,899)		193,041		(217)		7,064		(3,116)		200,105
Commercial - Government-sponsored enterprises		(27,342)		865,899		—		—		(27,342)		865,899
Collateralized mortgage obligations:
Government agency		(5,667)		463,392		—		—		(5,667)		463,392
Government-sponsored enterprises		(17,004)		1,237,282		—		—		(17,004)		1,237,282
Total available-for-sale securities with unrealized losses	$	(59,399)	$	3,499,015	$	(217)	$	7,064	$	(59,616)	$	3,506,079

	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