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Fair Value Measurements - Quantitative and Qualitative Information (Details) - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2018 | Dec. 31, 2017
Quantitative information about Level 3 fair value measurements |  |
Mortgage servicing rights, fair value | $ 7,812 | $ 6,944
Minimum |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) |  | 10.00%
Maximum |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) |  | 34.30%
Weighted Average |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) |  | 10.20%
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 |  |
Quantitative information about Level 3 fair value measurements |  |
Mortgage servicing rights, fair value | $ 7,812 |
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Minimum |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) | 10.00% |
Prepayment speed (as a percent) | 7.00% | 7.00%
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Maximum |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) | 417.60% |
Prepayment speed (as a percent) | 68.40% | 68.40%
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Weighted Average |  |
Quantitative information about Level 3 fair value measurements |  |
Discount rate (as a percent) | 10.20% |
Prepayment speed (as a percent) | 8.20% | 9.60%

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- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + 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 (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value. + 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 (bbb) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + 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/presentationRef -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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