Securities - Summary of Debt Securities with Unrealized Losses, Segregated by Duration of Unrealized Loss (Detail) $ in Thousands	Sep. 30, 2022 USD ($) Investments	Dec. 31, 2021 USD ($) Investments
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	183	21
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 1,476,418	$ 304,779
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	106,132	1,791
Available-for-sale Securities, 12 Months or Longer, Fair Value	21,044
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	1,813
Available-for-sale Securities, Fair Value, Total	1,497,462	304,779
Available-for-sale Securities, Unrealized Losses, Total	$ 107,945	$ 1,791
U.S. Treasuries [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	73	10
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 1,440,283	$ 298,080
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	102,906	1,766
Available-for-sale Securities, 12 Months or Longer, Fair Value	18,807
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	1,524
Available-for-sale Securities, Fair Value, Total	1,459,090	298,080
Available-for-sale Securities, Unrealized Losses, Total	$ 104,430	$ 1,766
U.S. Federal Agencies [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	2	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 515	$ 376
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	5	2
Available-for-sale Securities, Fair Value, Total	515	376
Available-for-sale Securities, Unrealized Losses, Total	$ 5	$ 2
Mortgage Backed Securities [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	98	7
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 13,199	$ 2,824
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	1,976	14
Available-for-sale Securities, 12 Months or Longer, Fair Value	2,042
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	283
Available-for-sale Securities, Fair Value, Total	15,241	2,824
Available-for-sale Securities, Unrealized Losses, Total	$ 2,259	$ 14
States and Political Subdivisions [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	7	2
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 2,049	$ 505
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	250	3
Available-for-sale Securities, 12 Months or Longer, Fair Value	195
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	6
Available-for-sale Securities, Fair Value, Total	2,244	505
Available-for-sale Securities, Unrealized Losses, Total	$ 256	$ 3
Asset backed Securities [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 12,968
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	399
Available-for-sale Securities, Fair Value, Total	12,968
Available-for-sale Securities, Unrealized Losses, Total	$ 399
Other Securities [Member]
Debt Securities, Available-for-Sale [Abstract]
Number of investments \| Investments	2	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 7,404	$ 2,994
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	596	6
Available-for-sale Securities, Fair Value, Total	7,404	2,994
Available-for-sale Securities, Unrealized Losses, Total	$ 596	$ 6

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

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-Publisher FASB
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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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