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Allowance for Credit Losses and Credit Quality of Loans, Allowance for Credit Losses on Off-Balance Sheet Credit Exposures (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for credit losses	$ 114,601	$ 100,400	$ 100,800	$ 96,800	$ 93,600	$ 92,000
Unfunded Commitment [Member]
Allowance for Credit Losses and Credit Quality of Loans [Abstract]
Allowance for credit losses	4,800		$ 5,100
Acquisition-related provision for credit losses	$ 800

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- References

No definition available.

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- Definition

Amount of contractually required allowance for credit losses at acquisition-related provision for credit losses.

+ References

No definition available.

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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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-Section 1405
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-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
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-Subparagraph (SX 210.9-03(7)(2))
-Publisher FASB
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Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 310
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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