Investments (Tables)

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost and Fair Value of Securities Available-for-Sale

The amortized cost and fair value of securities available for sale are as follows:

As of September 30, 2024 (dollars in thousands)	Amortized Cost		Allowance for credit losses(1)		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale:
Mortgage-backed securities	$	515,923	$	—	$	1,664	$	(54,875)	$	462,712
Utah Housing Corporation bonds	2,849		—		—		(318)		2,531
U.S. government-sponsored enterprises and Treasuries	997,530		—		—		(31,323)		966,207
Other securities	596,955		—		7,024		(12,824)		591,155
Total	$	2,113,257	$	—	$	8,688	$	(99,340)	$	2,022,605
As of December 31, 2023 (dollars in thousands)	Amortized Cost		Allowance for credit losses(1)		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale:
Mortgage-backed securities	$	468,204	$	—	$	703	$	(62,480)	$	406,427
Utah Housing Corporation bonds	3,408		—		—		(279)		3,129
U.S. government-sponsored enterprises and Treasuries	1,645,609		—		—		(66,870)		1,578,739
Other securities	446,763		—		603		(24,039)		423,327
Total	$	2,563,984	$	—	$	1,306	$	(153,668)	$	2,411,622

(1) Represents the amount of impairment that has resulted from credit-related factors and that was recognized in the consolidated balance sheets (as a credit loss expense on available-for-sale securities). The amount excludes unrealized losses related to non-credit factors.

Schedule of Available-for-Sale Securities, Continuous Unrealized Loss Position, Fair Value

The following table summarizes the amount of gross unrealized losses for our available-for-sale securities and the estimated fair value for securities having gross unrealized loss positions, categorized by length of time the securities have been in an unrealized loss position:

(Dollars in thousands)	Less than 12 months				12 months or more				Total
	Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value
As of September 30, 2024:
Mortgage-backed securities	$	(101)	$	34,601	$	(54,774)	$	309,842	$	(54,875)	$	344,443
Utah Housing Corporation bonds	—		—		(318)		2,531		(318)		2,531
U.S. government-sponsored enterprises and Treasuries	—		—		(31,323)		966,207		(31,323)		966,207
Other securities	(123)		22,933		(12,701)		206,952		(12,824)		229,885
Total	$	(224)	$	57,534	$	(99,116)	$	1,485,532	$	(99,340)	$	1,543,066
As of December 31, 2023:
Mortgage-backed securities	$	(531)	$	51,391	$	(61,949)	$	300,318	$	(62,480)	$	351,709
Utah Housing Corporation bonds	—		—		(279)		3,129		(279)		3,129
U.S. government-sponsored enterprises and Treasuries	—		—		(66,870)		1,578,739		(66,870)		1,578,739
Other securities	(2,221)		90,725		(21,818)		241,253		(24,039)		331,978
Total	$	(2,752)	$	142,116	$	(150,916)	$	2,123,439	$	(153,668)	$	2,265,555

Schedule of Amortized Cost and Fair Value of Securities by Contractual Maturities

As of September 30, 2024, the amortized cost and fair value of securities, by contractual maturities, are summarized below. Contractual maturities versus actual maturities may differ due to the effect of prepayments.

As of September 30, 2024 Year of Maturity (dollars in thousands)	Amortized Cost		Estimated Fair Value
2024	$	49,998	$	49,922
2025	299,564		296,634
2026	549,052		522,070
2027	98,916		97,582
2038	66		68
2039	561		563
2042	2,152		1,914
2043	3,813		3,512
2044	4,125		3,867
2045	4,567		4,170
2046	7,014		6,318
2047	6,980		6,339
2048	1,706		1,597
2049	14,973		13,648
2050	102,417		84,272
2051	146,699		119,429
2052	59,033		53,601
2053	312,243		310,480
2054	132,881		128,397
2055	75,043		73,470
2056	200,334		202,800
2058	41,120		41,952
Total	$	2,113,257	$	2,022,605