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Fair Value Measurements - Changes in Level 3 (Details) - USD ($) $ in Thousands | 9 Months Ended
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Sep. 30, 2020 | Sep. 30, 2019
US States and Political Subdivisions Debt Securities [Member] |  |
Changes in Level 3 |  |
Beginning balance | $ 5,419 | $ 8,165
Total gains or losses |  |
Included in earnings (or changes in net assets) |  | (25)
Included in other comprehensive income | (216) | 898
Purchases, issuances, sales, and settlements |  |
Purchases | 12,900 | 17,643
Settlements | (13,297) | (20,808)
Ending balance | 4,790 | 5,873
Changes in Level 3 (liabilities) |  |
Included in earnings (or changes in net assets) | (16) |
Mortgage Servicing Rights [Member] |  |
Changes in Level 3 |  |
Beginning balance | 5,935 | 7,357
Total gains or losses |  |
Included in earnings (or changes in net assets) |  | (2,384)
Purchases, issuances, sales, and settlements |  |
Issuances | 1,813 | 906
Settlements | (275) | (518)
Ending balance | 5,010 | $ 5,361
Changes in Level 3 (liabilities) |  |
Included in earnings (or changes in net assets) | $ (2,463) |

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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=117815213&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=117815213&loc=d3e19207-110258 + Details
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- Definition Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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- Definition Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in income from liability 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=117815213&loc=d3e19207-110258 + Details
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