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Short-term borrowings (Parenthetical) (Details) - Pledged | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Repurchase advance |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Federal Home Loan Bank interest rate | 0.59% | 1.48%
Fixed rate advances | Minimum |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Federal Home Loan Bank interest rate | 1.43% |
Fixed rate advances | Maximum |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Federal Home Loan Bank interest rate | 1.49% |
Cash management advance |  |
Assets Sold Under Agreements To Repurchase [Line Items] |  |
Federal Home Loan Bank interest rate | 0.00% | 0.59%

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- Definition Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, 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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