Acquisition of The Farmers Bancorp, Frankfort, Indiana	3 Months Ended
Acquisition of The Farmers Bancorp, Frankfort, Indiana	Mar. 31, 2026
Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract]
Acquisition of The Farmers Bancorp, Frankfort, Indiana	Acquisition of The Farmers Bancorp, Frankfort, Indiana On November 11, 2025, the Company entered into a definitive Agreement and Plan of Merger (the "Merger Agreement") with The Farmers Bancorp, Frankfort, Indiana ("Farmers Bancorp"), headquartered in Frankfort, Indiana. Pursuant to the Merger Agreement, Farmers Bancorp is expected to merge with and into the Company, with the Company surviving the holding company merger. Immediately following the holding company merger, The Farmers Bank, an Indiana state-chartered bank and wholly owned subsidiary of Farmers Bancorp, will merge with and into First Bank Richmond, with First Bank Richmond surviving the bank merger. Under the terms of the Merger Agreement, each outstanding share of Farmers Bancorp common stock will be converted into the right to receive 3.40 shares of the Company’s common stock (the "Exchange Ratio"), with cash paid in lieu of fractional shares (collectively, the "Merger Consideration"). In addition, (i) each unvested restricted stock unit award of Farmers Bancorp will automatically vest, and the underlying shares will be treated as outstanding and entitled to receive the Merger Consideration, less applicable tax withholding; and (ii) each unvested performance share award of Farmers Bancorp will be terminated and cashed out at target performance levels immediately prior to the effective time of the merger. Based on the Company’s closing stock price of $13.15 per share on November 10, 2025, the aggregate equity value of the Merger Consideration was approximately $82 million. The final value of the merger consideration will fluctuate until closing based on changes in the Company’s stock price. Upon completion of the merger, Farmers Bancorp shareholders are expected to own approximately 38% of the outstanding shares of the combined company. The merger has been approved by the boards of directors of both companies, and all required regulatory approvals have been received. A special meeting of Farmers Bancorp shareholders to approve the merger agreement and related transactions is scheduled for May 26, 2026. The Company will seek shareholder approval of the issuance of its shares in the transaction at its annual meeting of shareholders to be held on May 27, 2026. The transaction is expected to be completed at or around the end of the second quarter of 2026, subject to shareholder approvals and the satisfaction of customary closing conditions. The merger will be accounted for as a business combination under ASC 805, Business Combinations, with the Company expected to be the accounting acquirer. The combined company will continue to trade on the Nasdaq Capital Market under the ticker symbol "RMBI." The holding company will operate under the name "Richmond Mutual Bancorporation, Inc.," while the combined bank, subject to regulatory approval, will operate under the new name "First Bank Midwest". The administrative headquarters of the combined company will be located in Richmond, Indiana, and the administrative headquarters of the combined bank will be located in Frankfort, Indiana. The merger has not been completed as of March 31, 2026. Accordingly, the accompanying consolidated financial statements do not include the assets, liabilities, results of operations, or cash flows of Farmers Bancorp, and no purchase accounting adjustments have been recorded as of that date.