Investment Securities - Additional Information (Details) $ in Millions	9 Months Ended
Sep. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt securities, held-to-maturity, discount \| $	$ 69.2
Debt securities, available-for-sale, number of unrealized loss positions	98
Held-to-Maturity
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Available-for-sale debt securities transferred to held-to-maturity at fair value \| $	$ 1,000.0
U.S. Treasury securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt securities, available-for-sale, number of unrealized loss positions	12
U.S. government agency securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt securities, available-for-sale, number of unrealized loss positions	5
Residential mortgage-backed securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt securities, available-for-sale, number of unrealized loss positions	79
Credit risk transfer (“CRT”) securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Debt securities, available-for-sale, number of unrealized loss positions	2
Customer repurchase agreements
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits \| $	$ 18.6	$ 22.0
Deposits
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Available-for-sale debt securities pledged to secure certain customer repurchase agreements and deposits \| $	$ 1.4	$ 2.0

Debt Securities, Available-for-Sale, Amortized Cost, Transfer Amount, Excluding Accrued Interest

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- Definition

Debt Securities, Held-to-Maturity, Excluding Accrued Interest, Discount

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 45
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=120413173&loc=SL6242262-115580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI https://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 210
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=127002003&loc=SL6242269-115581

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- Definition

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922888-210455

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- Definition

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.

+ References

No definition available.

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