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Federal Home Loan Bank Advances - Additional Information (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
Federal Home Loan Bank Advances [Line Items] |  |
Federal home loan bank advances, acquisition accounting adjustments | $ 19,000 | $ 228,000
Federal home loan bank, required investment conversion ratio | 0.05 |
Additional borrowing capacity from FHLB | $ 795,000,000 | 647,900,000
Federal home loan bank advances maximum borrowing capacity as percentage of total assets | 35.00% |
Federal home loan bank, advances, putable option | $ 361,506,000 | $ 313,715,000
Ridgestone |  |
Federal Home Loan Bank Advances [Line Items] |  |
Federal home loan bank, advances, putable option | $ 1,500,000 |
Minimum |  |
Federal Home Loan Bank Advances [Line Items] |  |
Federal home loan bank advances, Fixed interest rate | 1.32% |
Federal home loan bank fixed rate advances, maturity date | 2018-01 |
Maximum |  |
Federal Home Loan Bank Advances [Line Items] |  |
Federal home loan bank advances, Fixed interest rate | 3.22% |
Federal home loan bank fixed rate advances, maturity date | 2018-03 |

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- Definition Fixed interest rate of advances made and reported by Federal Home Loan Bank (FHLBank). + References No definition available. + Details
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- Definition Federal home loan bank advances maximum borrowing capacity as percentage of total assets. + References No definition available. + Details
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- Definition Ratio applied to the conversion of required investment in Federal Home Loan Bank (FHL Bank) $1 for every $ 20. + References No definition available. + Details
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- Definition Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions. + References No definition available. + Details
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- Definition Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(3)(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22 (b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: 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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