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Junior Subordinated Debentures - Issuance (Details) - USD ($) $ in Thousands | 1 Months Ended | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | --- | ---
Apr. 30, 2007 | Mar. 31, 2025 | Jun. 15, 2017 | Dec. 31, 2024 | Mar. 31, 2024
Junior subordinated debentures |  |  |  |  |
Junior subordinated debentures |  | $ 25,773 |  | $ 25,773 |
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) |  |  | 6.77% |  |
Basis points added to cash distribution floating rate base (as a percent) |  | 1.50% |  |  |
Cash distribution, floating rate base |  | three-month SOFR |  |  |
Amortization period |  | 30 years |  |  |
Old Second Capital Trust II | Debt Instrument, Redemption, Period One |  |  |  |  |
Junior subordinated debentures |  |  |  |  |
Interest rate (as a percent) |  | 4.53% |  |  | 4.37%
Junior Subordinated Debentures |  |  |  |  |
Junior subordinated debentures |  |  |  |  |
Junior Subordinated Debentures issuance cost |  | $ 1,000 |  | $ 1,000 |
Junior Subordinated Debentures | Old Second Capital Trust II |  |  |  |  |
Junior subordinated debentures |  |  |  |  |
Junior subordinated debentures |  | $ 25,800 |  |  |

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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://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
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- Definition The cash inflow from issuance of preferred stocks by a business trust or other special purpose entity, mainly established by a bank holding entity, to third party investors. The trust's assets are deeply subordinated debentures of the bank holding entity. Most trust preferred securities are subject to a mandatory redemption upon the repayment of the debentures. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-14 + Details
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