Subordinated Debentures Schedule of Subordinated Debentures Outstanding (Details) - USD ($) $ in Thousands |
Mar. 31, 2026 |
Dec. 31, 2025 |
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| Debt Instrument [Line Items] | ||
| Subordinated debentures | $ 128,507 | $ 128,466 |
| First Commonwealth Bank 2033 [Member] | ||
| Debt Instrument [Line Items] | ||
| Subordinated debentures | 49,498 | 49,480 |
| First Commonwealth Capital Trust II [Member] | ||
| Debt Instrument [Line Items] | ||
| Subordinated debentures | 30,929 | 30,929 |
| First Commonwealth Capital Trust III [Member] | ||
| Debt Instrument [Line Items] | ||
| Subordinated debentures | 41,238 | 41,238 |
| First Commonwealth Financial Corporation | ||
| Debt Instrument [Line Items] | ||
| Subordinated debentures | $ 6,842 | $ 6,819 |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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