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Fair Value Measurements - Changes in Level 3 (Details) - USD ($) $ in Thousands | 6 Months Ended
--- | ---
Jun. 30, 2018 | Jun. 30, 2017
Changes in Level 3 |  |
Beginning balance |  | $ 3,119
Total gains or losses |  |
Included in other comprehensive income |  | (1)
Purchases, issuances, sales, and settlements |  |
Settlements |  | (463)
Ending balance |  | 2,678
Changes in Level 3 (liabilities) |  |
Included in earnings (or changes in net assets) |  | 23
Collateralized loan obligations |  |
Changes in Level 3 |  |
Beginning balance | $ 2,268 |
Total gains or losses |  |
Included in other comprehensive income | 31 |
Purchases, issuances, sales, and settlements |  |
Settlements | (554) |
Ending balance | 1,771 |
Changes in Level 3 (liabilities) |  |
Included in earnings (or changes in net assets) | 26 |
States and political subdivisions |  |
Changes in Level 3 |  |
Beginning balance | 14,261 | 22,226
Total gains or losses |  |
Included in other comprehensive income | (551) | (289)
Purchases, issuances, sales, and settlements |  |
Purchases | 19,934 | 10,456
Settlements | (15,195) | (12,045)
Ending balance | 18,449 | 20,348
Mortgage servicing rights |  |
Changes in Level 3 |  |
Beginning balance | 6,944 | 6,489
Total gains or losses |  |
Included in earnings (or changes in net assets) |  | (280)
Purchases, issuances, sales, and settlements |  |
Issuances | 668 | 601
Settlements | (320) | (282)
Ending balance | 7,812 | $ 6,528
Changes in Level 3 (liabilities) |  |
Included in earnings (or changes in net assets) | $ 520 |

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- Definition Amount of gain (loss) recognized in the income statement for 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (loss) for 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=66048111&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66048111&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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