Investment Securities (Tables)

3 Months Ended

Mar. 31, 2022

Investment Securities

Schedule of amortized cost and fair value of securities

	March 31, 2022								December 31, 2021
	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	$	213,572	$	—	$	(14,028)	$	199,544	$	196,662	$	125	$	(4,224)	$	192,563
Mortgage-backed securities:
Residential - Government agency		128,080		—		(5,115)		122,965		135,764		1,791		(291)		137,264
Residential - Government-sponsored enterprises		1,450,070		428		(88,153)		1,362,345		1,496,605		6,914		(12,419)		1,491,100
Commercial - Government agency		358,910		53		(25,874)		333,089		392,443		1,741		(6,521)		387,663
Commercial - Government-sponsored enterprises		1,426,831		—		(176,997)		1,249,834		1,415,511		2,646		(48,714)		1,369,443
Collateralized mortgage obligations:
Government agency		2,153,236		59		(143,514)		2,009,781		2,103,187		7,768		(31,432)		2,079,523
Government-sponsored enterprises		2,719,829		3		(210,125)		2,509,707		2,671,131		3,608		(53,695)		2,621,044
Collateralized loan obligations		221,607		25		(748)		220,884		105,245		2		—		105,247
Debt securities issued by states and political subdivisions		61,035		—		(6,800)		54,235		44,185		—		—		44,185
Total available-for-sale securities	$	8,733,170	$	568	$	(671,354)	$	8,062,384	$	8,560,733	$	24,595	$	(157,296)	$	8,428,032

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

	March 31, 2022
	Amortized		Fair
(dollars in thousands)	Cost		Value
Due in one year or less	$	30,148	$	29,944
Due after one year through five years		39,854		38,512
Due after five years through ten years		178,200		172,750
Due after ten years		248,012		233,457
		496,214		474,663
Mortgage-backed securities:
Residential - Government agency		128,080		122,965
Residential - Government-sponsored enterprises		1,450,070		1,362,345
Commercial - Government agency		358,910		333,089
Commercial - Government-sponsored enterprises		1,426,831		1,249,834
Total mortgage-backed securities		3,363,891		3,068,233
Collateralized mortgage obligations:
Government agency		2,153,236		2,009,781
Government-sponsored enterprises		2,719,829		2,509,707
Total collateralized mortgage obligations		4,873,065		4,519,488
Total available-for-sale securities	$	8,733,170	$	8,062,384

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

	Time in Continuous Loss as of March 31, 2022
	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	$	(4,314)	$	93,417	$	(9,714)	$	106,127	$	(14,028)	$	199,544
Mortgage-backed securities:
Residential - Government agency		(5,115)		122,965		—		—		(5,115)		122,965
Residential - Government-sponsored enterprises		(75,047)		1,209,850		(13,106)		106,145		(88,153)		1,315,995
Commercial - Government agency		(10,635)		169,320		(15,239)		153,626		(25,874)		322,946
Commercial - Government-sponsored enterprises		(71,323)		562,986		(105,674)		682,848		(176,997)		1,245,834
Collateralized mortgage obligations:
Government agency		(135,357)		1,904,905		(8,157)		73,679		(143,514)		1,978,584
Government-sponsored enterprises		(161,761)		2,012,931		(48,364)		465,051		(210,125)		2,477,982
Collateralized loan obligations:		(748)		79,181		—		—		(748)		79,181
Debt securities issued by states and political subdivisions		(6,800)		54,235		—		—		(6,800)		54,235
Total available-for-sale securities with unrealized losses	$	(471,100)	$	6,209,790	$	(200,254)	$	1,587,476	$	(671,354)	$	7,797,266

	Time in Continuous Loss as of December 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	$	(3,355)	$	134,468	$	(869)	$	16,642	$	(4,224)	$	151,110
Mortgage-backed securities:
Residential - Government agency		(291)		51,231		—		—		(291)		51,231
Residential - Government-sponsored enterprises		(10,876)		1,230,104		(1,543)		32,415		(12,419)		1,262,519
Commercial - Government agency		(5,239)		186,024		(1,282)		26,063		(6,521)		212,087
Commercial - Government-sponsored enterprises		(22,179)		744,819		(26,535)		397,123		(48,714)		1,141,942
Collateralized mortgage obligations:
Government agency		(31,432)		1,441,848		—		—		(31,432)		1,441,848
Government-sponsored enterprises		(52,551)		2,255,535		(1,144)		24,959		(53,695)		2,280,494
Total available-for-sale securities with unrealized losses	$	(125,923)	$	6,044,029	$	(31,373)	$	497,202	$	(157,296)	$	6,541,231