Investments (Tables)

12 Months Ended

Dec. 31, 2021

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 December 31, 2021 (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	$	376,313	$	—	$	1,857	$	(7,073)	$	371,097
Utah Housing Corporation bonds	6,943		—		18		—		6,961
U.S. government-sponsored enterprises and Treasuries	1,958,943		—		603		(11,893)		1,947,653
Other securities	193,369		—		439		(1,563)		192,245
Total	$	2,535,568	$	—	$	2,917	$	(20,529)	$	2,517,956
As of December 31, 2020 (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	$	308,913	$	—	$	6,095	$	(134)	$	314,874
Utah Housing Corporation bonds	12,357		—		210		—		12,567
U.S. government-sponsored enterprises and Treasuries	1,596,890		—		3,395		—		1,600,285
Other securities	68,797		—		462		(351)		68,908
Total	$	1,986,957	$	—	$	10,162	$	(485)	$	1,996,634

(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.

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:

	Less than 12 months				12 months or more				Total
As of December 31, (dollars in thousands)	Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value
2021:
Mortgage-backed securities	$	(5,534)	$	261,404	$	(1,540)	$	36,587	$	(7,074)	$	297,991
Utah Housing Corporation bonds	—		—		—		—		—		—
U.S. government-sponsored enterprises and Treasuries	(11,892)		1,199,367		—		—		(11,892)		1,199,367
Other securities	(1,563)		132,884		—		—		(1,563)		132,884
Total	$	(18,989)	$	1,593,655	$	(1,540)	$	36,587	$	(20,529)	$	1,630,242
2020:
Mortgage-backed securities	$	(134)	$	46,011	$	—	$	—	$	(134)	$	46,011
Utah Housing Corporation bonds	—		—		—		—		—		—
U.S. government-sponsored enterprises and Treasuries	—		—		—		—		—		—
Other securities	(351)		30,441		—		—		(351)		30,441
Total	$	(485)	$	76,452	$	—	$	—	$	(485)	$	76,452

Amortized cost and fair value of securities by contractual maturities

As of December 31, 2021, 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 December 31, 2021 Year of Maturity (Dollars in thousands)	Amortized Cost		Estimated Fair Value
2022	$	850,032	$	850,326
2023	162,617		162,003
2024	398,583		394,941
2026	547,712		540,382
2038	74		79
2039	1,029		1,120
2042	3,183		3,175
2043	5,599		5,797
2044	7,620		7,881
2045	6,764		6,968
2046	10,629		10,818
2047	12,611		12,822
2048	2,961		3,025
2049	19,828		20,458
2050	134,707		131,063
2051	178,250		174,853
2053	141,251		140,260
2054	52,118		51,985
Total	$	2,535,568	$	2,517,956