Securities - Summary of Debt Securities with Unrealized Losses, Segregated by Duration of Unrealized Loss (Detail) $ in Thousands	Mar. 31, 2022 USD ($) Investments	Dec. 31, 2021 USD ($) Investments
Debt Securities, Available-for-sale [Abstract]
Number of investments \| Investments	123	21
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 1,069,359	$ 304,779
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	40,013	1,791
Available-for-sale Securities, 12 Months or Longer, Fair Value	4,876
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	121
Available-for-sale Securities, Fair Value, Total	1,074,235	304,779
Available-for-sale Securities, Unrealized Losses, Total	$ 40,134	$ 1,791
U.S. Treasuries [Member]
Debt Securities, Available-for-sale [Abstract]
Number of investments \| Investments	50	10
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 1,030,589	$ 298,080
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	38,875	1,766
Available-for-sale Securities, 12 Months or Longer, Fair Value	4,876
Available-for-sale Securities, 12 Months or Longer, Unrealized Losses	121
Available-for-sale Securities, Fair Value, Total	1,035,465	298,080
Available-for-sale Securities, Unrealized Losses, Total	$ 38,996	$ 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	$ 403	$ 376
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	2	2
Available-for-sale Securities, Fair Value, Total	403	376
Available-for-sale Securities, Unrealized Losses, Total	$ 2	$ 2
Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Number of investments \| Investments	63	7
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 20,084	$ 2,824
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	798	14
Available-for-sale Securities, Fair Value, Total	20,084	2,824
Available-for-sale Securities, Unrealized Losses, Total	$ 798	$ 14
States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Abstract]
Number of investments \| Investments	6	2
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 2,177	$ 505
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	85	3
Available-for-sale Securities, Fair Value, Total	2,177	505
Available-for-sale Securities, Unrealized Losses, Total	$ 85	$ 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	$ 13,280
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	79
Available-for-sale Securities, Fair Value, Total	13,280
Available-for-sale Securities, Unrealized Losses, Total	$ 79
Other Securities [Member]
Debt Securities, Available-for-sale [Abstract]
Number of investments \| Investments	1	1
Available-for-sale Securities, Less than 12 Months, Fair Value	$ 2,826	$ 2,994
Available-for-sale Securities, Less than 12 Months, Unrealized Losses	174	6
Available-for-sale Securities, Fair Value, Total	2,826	2,994
Available-for-sale Securities, Unrealized Losses, Total	$ 174	$ 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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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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