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Short-term borrowings (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Amount of Advances | $ 4,785 | $ 12,876
Weighted Average |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Weighted Average Interest Rate | 1.70% | 2.69%
Pledged |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Amount of Advances | $ 215,000 | $ 120,000
Pledged | Weighted Average |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Weighted Average Interest Rate | 1.46% | 0.63%
Pledged | Repurchase advance |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Amount of Advances | $ 125,000 | $ 100,000
Pledged | Repurchase advance | Weighted Average |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Weighted Average Interest Rate | 1.47% | 0.63%
Pledged | Fixed rate advances |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Amount of Advances | $ 90,000 | $ 0
Pledged | Fixed rate advances | Weighted Average |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Weighted Average Interest Rate | 1.45% | 0.00%
Pledged | Cash management advance |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Amount of Advances | $ 0 | $ 20,000
Pledged | Cash management advance | Weighted Average |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Weighted Average Interest Rate | 0.00% | 0.59%

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- Definition Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
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- Definition States the interest rate applicable to Federal Home Loan Bank advances outstanding as of the Balance Sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
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