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Fair Value (Narrative) (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | Dec. 31, 2020
Loans Held-for-sale |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |
(Losses)/gains from changes in fair value included in earnings | $ (79,000) | $ 233,000 | $ (159,000) | $ 330,000 |
Fair Value, Measurements, Recurring |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |
Fair value of securities held | 1,696,225,000 |  | 1,696,225,000 |  | $ 1,217,852,000
Fair Value, Measurements, Recurring | Obligations of State and Political Subdivisions |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |
Fair value of securities held | 833,453,000 |  | 833,453,000 |  | 581,247,000
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |
Fair value of securities held | 0 |  | 0 |  | 497,000
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring | Obligations of State and Political Subdivisions |  |  |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |  |  |
Fair value of securities held | 0 |  | 0 |  | $ 497,000
Losses from changes in fair value included in other comprehensive income | $ 0 | $ (3,000) | $ (2,000) | $ (26,000) |

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- Definition Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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