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Junior Subordinated Debentures - Issuance (Details) $ in Thousands |  | 1 Months Ended | 6 Months Ended | 7 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Dec. 31, 2018 USD ($) | Apr. 30, 2007 USD ($) | Jul. 31, 2003 USD ($) | Jun. 30, 2003 USD ($) | Jun. 15, 2017 | Dec. 31, 2017 USD ($) | Dec. 31, 2018 USD ($) item | Dec. 31, 2017 USD ($)
Junior subordinated debentures |  |  |  |  |  |  |  |
Junior subordinated debentures | $ 57,686 |  |  |  |  | $ 57,639 | $ 57,686 | $ 57,639
Junior Subordinated Debentures issuance cost | $ 692 |  |  |  |  | $ 739 | $ 692 | $ 739
Old Second Capital Trust I |  |  |  |  |  |  |  |
Junior subordinated debentures |  |  |  |  |  |  |  |
Proceeds from sale of cumulative trust preferred securities |  |  | $ 4,100 | $ 27,500 |  |  |  |
Maturity Period |  |  |  |  |  |  | 30 years |
Cash distribution rate of trust preferred securities (as a percent) |  |  |  |  |  |  | 7.80% |
Amortization period |  |  |  |  |  |  | 30 years |
Old Second Capital Trust II |  |  |  |  |  |  |  |
Junior subordinated debentures |  |  |  |  |  |  |  |
Proceeds from sale of cumulative trust preferred securities |  | $ 25,000 |  |  |  |  |  |
Maturity Period |  |  |  |  |  |  | 30 years |
Cash distribution fixed rate of trust preferred securities (as a percent) | 4.37% |  |  |  | 6.77% |  |  | 4.30%
Basis points added to cash distribution floating rate base (as a percent) |  |  |  |  |  | 1.50% |  |
Cash distribution, floating rate base |  |  |  |  |  |  | three-month LIBOR |
Junior subordinated debentures |  |  |  |  |  |  |  |
Junior subordinated debentures |  |  |  |  |  |  |  |
Interest Payment Deferment Period | item |  |  |  |  |  |  | 20 |
Junior subordinated debentures | Old Second Capital Trust I |  |  |  |  |  |  |  |
Junior subordinated debentures |  |  |  |  |  |  |  |
Junior subordinated debentures | $ 32,600 |  |  |  |  |  | $ 32,600 |
Junior subordinated debentures | Old Second Capital Trust II |  |  |  |  |  |  |  |
Junior subordinated debentures |  |  |  |  |  |  |  |
Junior subordinated debentures | $ 25,800 |  |  |  |  |  | $ 25,800 |

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- Definition The percentage points added to the reference rate to compute the variable rate on the trust preferred securities. + References No definition available. + Details
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- Definition Represents the fixed annual rate of cash distributions on the securities. + References No definition available. + Details
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- Definition The reference rate for the variable rate of the trust preferred securities, such as LIBOR or the US treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. + References No definition available. + Details
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- Definition Represents the amortization period of the costs associated with the issuance of the trust preferred securities. + References No definition available. + Details
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- Definition Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399 + Details
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- Definition Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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