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Subordinated Debt - Schedule of Subordinated Debt (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Debt Instrument [Line Items] |  |
Unamortized Discount and Debt Issuance Costs | $ (1,163) | $ (1,274)
Subordinated Debt |  |
Debt Instrument [Line Items] |  |
Principal | 35,000 | 38,000
Unamortized Discount and Debt Issuance Costs | (1,163) | (1,274)
Subordinated Debt | 2021 Debenture |  |
Debt Instrument [Line Items] |  |
Principal | 0 | 3,000
Unamortized Discount and Debt Issuance Costs | 0 | 0
Subordinated Debt | 2025 Note |  |
Debt Instrument [Line Items] |  |
Principal | 10,000 | 10,000
Unamortized Discount and Debt Issuance Costs | (168) | (186)
Subordinated Debt | 2026 Notes |  |
Debt Instrument [Line Items] |  |
Principal | 25,000 | 25,000
Unamortized Discount and Debt Issuance Costs | $ (995) | $ (1,088)

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