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Long-Term Borrowings and Subordinated Debt - Schedule of Junior Subordinated Debt Securities (Detail) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 45,619 | $ 45,619 | $ 45,619
Interest Rate at December 31, 2015 | 0.81% | 3.00% | 3.01%
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 |  |
Interest Rate at December 31, 2015 | 2.11% |  |
2006 Junior Subordinated Debt | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread on base interest rate | 1.60% |  |
2008 Junior Subordinated Debt-Trust Preferred Securities |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 20,619 | $ 20,619 | $ 20,619
Trust Preferred Securities | $ 20,619 |  |
Stated Maturity Date | Mar. 15, 2038 |  |
Optional redemption date at par | Any time after 3/15/2013 |  |
Regulatory Capital | Tier 1 |  |
Interest Rate at December 31, 2015 | 4.01% |  |
2008 Junior Subordinated Debt-Trust Preferred Securities | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread on base interest rate | 3.50% |  |
2008 Junior Subordinated Debt |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 20,000 |  |
Stated Maturity Date | Jun. 15, 2018 |  |
Optional redemption date at par | Any time after 6/15/2013 |  |
Regulatory Capital | Tier 2 |  |
Interest Rate at December 31, 2015 | 0.00% |  |
2008 Junior Subordinated Debt | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread on base interest rate | 3.50% |  |
2008 Junior Subordinated Debt |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Junior subordinated debt securities | $ 25,000 |  |
Stated Maturity Date | May 30, 2018 |  |
Optional redemption date at par | Any time after 5/30/2013 |  |
Regulatory Capital | Tier 2 |  |
Interest Rate at December 31, 2015 | 0.00% |  |
2008 Junior Subordinated Debt | 3-Month LIBOR |  |  |
Junior Subordinated Debentures [Line Items] |  |  |
Basis spread on base interest rate | 2.50% |  |

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