Securities - Summary of Debt Securities with Unrealized Losses, Segregated by Duration of Unrealized Loss (Detail) $ in Thousands	Dec. 31, 2022 USD ($) Investments	Dec. 31, 2021 USD ($) Investments
Available for Sale
Number of investments \| Investments	179	21
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 818,115	$ 304,779
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	29,153	1,791
Available-for-sale Securities, 12 Months or Longer, Fair Value	698,341
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	64,771
Available-for-sale Securities, Fair Value, Total	1,516,456	304,779
Available-for-sale Securities, Unrealized Losses, Total	$ 93,924	$ 1,791
U.S. Treasuries [Member]
Available for Sale
Number of investments \| Investments	74	10
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 787,925	$ 298,080
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	27,078	1,766
Available-for-sale Securities, 12 Months or Longer, Fair Value	689,939
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	63,621
Available-for-sale Securities, Fair Value, Total	1,477,864	298,080
Available-for-sale Securities, Unrealized Losses, Total	$ 90,699	$ 1,766
U.S. Federal Agencies [Member]
Available for Sale
Number of investments \| Investments	1	1
Available-for-sale Securities, Less than 12 Months, Fair Value		$ 376
Available-for-sale Securities, Less than 12 Months, Unrealized Losses		2
Available-for-sale Securities, 12 Months or Longer, Fair Value	$ 349
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	1
Available-for-sale Securities, Fair Value, Total	349	376
Available-for-sale Securities, Unrealized Losses, Total	$ 1	$ 2
Mortgage Backed Securities [Member]
Available for Sale
Number of investments \| Investments	92	7
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 10,001	$ 2,824
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	1,239	14
Available-for-sale Securities, 12 Months or Longer, Fair Value	5,055
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	645
Available-for-sale Securities, Fair Value, Total	15,056	2,824
Available-for-sale Securities, Unrealized Losses, Total	$ 1,884	$ 14
States and Political Subdivisions [Member]
Available for Sale
Number of investments \| Investments	8	2
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 2,308	$ 505
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	184	3
Available-for-sale Securities, 12 Months or Longer, Fair Value	464
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	37
Available-for-sale Securities, Fair Value, Total	2,772	505
Available-for-sale Securities, Unrealized Losses, Total	$ 221	$ 3
Asset backed Securities [Member]
Available for Sale
Number of investments \| Investments	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 13,010
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	361
Available-for-sale Securities, Fair Value, Total	13,010
Available-for-sale Securities, Unrealized Losses, Total	$ 361
Other Securities [Member]
Available for Sale
Number of investments \| Investments	3	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 4,871	$ 2,994
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	291	6
Available-for-sale Securities, 12 Months or Longer, Fair Value	2,534
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	467
Available-for-sale Securities, Fair Value, Total	7,405	2,994
Available-for-sale Securities, Unrealized Losses, Total	$ 758	$ 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.

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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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