Borrowings - Summary of Bancorp's Short-term Borrowings (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2023	Dec. 31, 2022
Federal Reserve Bank Advances
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 0	$ 0
Average balance during the period	$ 160,571	$ 0
Weighted-average interest rate during the period	5.23%	0.00%
FHLB advances
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 0	$ 775,000
Average balance during the period	$ 116,862	$ 144,918
Weighted-average interest rate during the period	5.16%	1.07%
Federal Funds Purchased
Short-term Debt [Line Items]
Maximum outstanding at any month end	$ 0	$ 895,000
Average balance during the period	$ 5,055	$ 349,581
Weighted-average interest rate during the period	4.97%	1.66%

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No definition available.

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Weighted average interest rate of short-term debt outstanding calculated at point in time.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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- Definition

For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph (a)
-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1402
-Paragraph (b)
-Subparagraph (1)
-Publisher SEC

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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