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Fair Value Measurements - Recurring (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Assets: |  |  |
Securities available-for-sale | $ 543,644 | $ 543,644 | $ 541,439
Mortgage servicing rights | 7,812 |  | 6,944
U.S. Treasury |  |  |
Assets: |  |  |
Securities available-for-sale | 3,876 |  | 3,947
U.S. government agencies |  |  |
Assets: |  |  |
Securities available-for-sale | 12,216 |  | 13,061
U.S. government agency mortgage-backed |  |  |
Assets: |  |  |
Securities available-for-sale | 13,407 |  |
States and political subdivisions |  |  |
Assets and liabilities measured at fair value on a recurring basis |  |  |
Purchases | 19,934 | $ 10,456 |
Assets: |  |  |
Securities available-for-sale | 276,112 |  | 278,092
Corporate bonds |  |  |
Assets: |  |  |
Securities available-for-sale | 700 |  | 833
Collateralized mortgage obligations |  |  |
Assets: |  |  |
Securities available-for-sale | 61,432 |  | 65,939
Asset-backed securities |  |  |
Assets: |  |  |
Securities available-for-sale | 109,263 |  | 112,932
Collateralized loan obligations |  |  |
Assets: |  |  |
Securities available-for-sale | 66,638 |  | 54,421
Level 1 |  |  |
Assets: |  |  |
Securities available-for-sale | 3,876 |  | 3,947
Level 2 |  |  |
Assets: |  |  |
Securities available-for-sale | 519,548 |  | 520,963
Loans held-for-sale | 5,206 |  | 4,067
Liabilities: |  |  |
Other liabilities |  |  | 1,287
Level 3 |  |  |
Assets: |  |  |
Securities available-for-sale | 20,220 |  | 16,529
Recurring |  |  |
Assets: |  |  |
Securities available-for-sale |  |  | 13,061
Total financial assets | 559,210 |  | 553,415
Liabilities: |  |  |
Total | 2,287 |  | 2,014
Recurring | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Loans held-for-sale | 5,206 |  | 4,067
Mortgage servicing rights | 7,812 |  | 6,944
Recurring | Interest rate swap agreements net of swap credit valuation |  |  |
Liabilities: |  |  |
Other liabilities | 2,287 |  | 2,014
Recurring | Interest rate swap agreements net of swap credit valuation | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Other assets | 2,287 |  | 727
Recurring | Forward MBS contracts and forward loan contracts | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Other assets | 261 |  | 238
Recurring | U.S. Treasury |  |  |
Assets: |  |  |
Securities available-for-sale |  |  | 3,947
Recurring | U.S. Treasury | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 3,876 |  |
Recurring | U.S. government agencies | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 12,216 |  |
Recurring | U.S. government agency mortgage-backed | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 13,407 |  | 12,214
Recurring | States and political subdivisions | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 276,112 |  | 278,092
Recurring | Corporate bonds | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 700 |  | 833
Recurring | Collateralized mortgage obligations | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 61,432 |  | 65,939
Recurring | Asset-backed securities | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 109,263 |  | 112,932
Recurring | Collateralized loan obligations | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 66,638 |  | 54,421
Recurring | Level 1 |  |  |
Assets: |  |  |
Total financial assets | 3,876 |  | 3,947
Recurring | Level 1 | U.S. Treasury |  |  |
Assets: |  |  |
Securities available-for-sale |  |  | 3,947
Recurring | Level 1 | U.S. Treasury | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 3,876 |  |
Recurring | Level 2 |  |  |
Assets: |  |  |
Securities available-for-sale |  |  | 13,061
Total financial assets | 527,302 |  | 525,995
Liabilities: |  |  |
Total | 2,287 |  | 2,014
Recurring | Level 2 | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Loans held-for-sale | 5,206 |  | 4,067
Recurring | Level 2 | Interest rate swap agreements net of swap credit valuation |  |  |
Liabilities: |  |  |
Other liabilities | 2,287 |  | 2,014
Recurring | Level 2 | Interest rate swap agreements net of swap credit valuation | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Other assets | 2,287 |  | 727
Recurring | Level 2 | Forward MBS contracts and forward loan contracts | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Other assets | 261 |  | 238
Recurring | Level 2 | U.S. government agencies | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 12,216 |  |
Recurring | Level 2 | U.S. government agency mortgage-backed | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 13,407 |  | 12,214
Recurring | Level 2 | States and political subdivisions | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 257,663 |  | 263,831
Recurring | Level 2 | Corporate bonds | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 700 |  | 833
Recurring | Level 2 | Collateralized mortgage obligations | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 59,661 |  | 63,671
Recurring | Level 2 | Asset-backed securities | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 109,263 |  | 112,932
Recurring | Level 2 | Collateralized loan obligations | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 66,638 |  | 54,421
Recurring | Level 3 |  |  |
Assets: |  |  |
Total financial assets | 28,032 |  | 23,473
Recurring | Level 3 | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Mortgage servicing rights | 7,812 |  | 6,944
Recurring | Level 3 | States and political subdivisions | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | 18,449 |  | 14,261
Recurring | Level 3 | Collateralized mortgage obligations | Finite-Lived Intangible Assets [Member] |  |  |
Assets: |  |  |
Securities available-for-sale | $ 1,771 |  | $ 2,268

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