Investment Securities - Additional Information (Detail)	3 Months Ended
Mar. 31, 2023 USD ($) security assetBackedSecurity corporateNote	Mar. 31, 2022 USD ($) assetBackedSecurity	Dec. 31, 2022 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of investment securities available for sale	$ 0	$ 155,954,000
Number of available-for-sale investment securities, unrealized loss position, less than twelve month category \| security	50
Number of available-for-sale investment securities, unrealized loss position, twelve month or more category \| security	112
Number of asset-backed securities with deterioration in future estimated cash flows \| assetBackedSecurity	4	4
Number of corporate notes with deterioration in future estimated cash flows \| corporateNote	6
Number of available-for-sale investment securities, unrealized loss position \| security	162		156
Debt securities, available for sale	$ 2,900,259,000		$ 2,961,015,000
Debt securities, held-to-maturity, allowance for credit loss, excluding accrued interest	0		0
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available for sale	147,935,000		160,542,000
Debt securities, held-to-maturity, allowance for credit loss, excluding accrued interest	0		0
Asset Pledged as Collateral
Debt Securities, Available-for-sale [Line Items]
Debt securities, available for sale	1,600,000,000
Debt securities	$ 443,800,000		$ 16,700,000

Number of Asset-Backed Securities With Deterioration In Future Estimated Cash Flows

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- Definition

Number of Corporate Notes With Deterioration In Future Estimated Cash Flows

+ References

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- Definition

Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

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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 continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
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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 continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Publisher FASB
-Name Accounting Standards Codification
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 320
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Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

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- Definition

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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