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Long-Term Borrowings and Subordinated Debt - Key Terms of Junior Subordinated Debt Securities (Details) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 45,619 | $ 45,619 | $ 45,619
December 31, 2017 | 1.88% | 2.91% | 0.81%
2006 Junior Subordinated Debt |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 25,000 | $ 25,000 | $ 25,000
Stated Maturity Date | Dec. 15, 2036 |  |
Optional redemption date at par | Any time after 9/15/2011 |  |
Regulatory Capital | Tier 2 |  |
December 31, 2017 | 2.92% |  |
2006 Junior Subordinated Debt | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread over variable rate | 160.00% |  |
2008 Trust Preferred Securities |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 20,619 | $ 20,619 | $ 20,619
Stated Maturity Date | Mar. 15, 2038 |  |
Optional redemption date at par | Any time after 3/15/2013 |  |
Regulatory Capital | Tier 1 |  |
December 31, 2017 | 4.82% |  |
2008 Trust Preferred Securities | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread over variable rate | 350.00% |  |

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- Definition Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments, excluding current portion. + References Reference 1: 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) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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