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Fair Value Measurements - Quantitative and Qualitative Information (Details) $ in Thousands | Mar. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Mar. 31, 2018 USD ($)
--- | --- | --- | ---
Quantitative information about Level 3 fair value measurements |  |  |
Mortgage servicing rights, fair value | $ 6,715 | $ 7,357 |
Securities available-for-sale, at fair value | 509,090 | 541,248 | $ 509,090
Fair Value, Inputs, Level 3 [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Mortgage servicing rights, fair value | 6,715 | 7,357 |
Securities available-for-sale, at fair value | 19,556 | 8,165 | 26,500
US States and Political Subdivisions Debt Securities [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Securities available-for-sale, at fair value | 281,172 | 274,067 |
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Securities available-for-sale, at fair value | 19,600 |  |
Collateralized Mortgage Obligations [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Securities available-for-sale, at fair value | $ 64,330 | $ 64,429 |
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Securities available-for-sale, at fair value |  |  | $ 2,100
Measurement Input, Discount Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input |  | 10.2 |
Measurement Input, Discount Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 10.0 | 10.0 |
Measurement Input, Discount Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 17.0 | 229.7 |
Measurement Input, Discount Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 10.1 |  |
Measurement Input, Constant Prepayment Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input |  | 9.6 |
Measurement Input, Constant Prepayment Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 7.0 | 7.0 |
Measurement Input, Constant Prepayment Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 69.0 | 68.9 |
Measurement Input, Constant Prepayment Rate | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted Average [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Servicing Asset, Measurement Input | 11.5 |  |
Fair Value, Measurements, Recurring [Member] |  |  |
Quantitative information about Level 3 fair value measurements |  |  |
Securities available-for-sale, at fair value |  | $ 10,951 |

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746 + Details
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