Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 30, 2018
Basis of Presentation
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements include the accounts of Merchants Bancorp, a registered bank holding company (the “Company”) and its wholly owned subsidiaries, Joy State Bank (which was renamed Farmers-Merchants Bank of Illinois on October 22, 2018), Merchants Bank of Indiana (the “Bank”), and the Bank’s subsidiaries, Merchants Capital Corp. (“MCC,” formerly known as P/R Mortgage and Investment Corp. prior to October 1, 2018), Ash Realty Holdings, LLC (“Ash Realty”), Natty Mac Funding, Inc. (“NMF”), MBI Midtown West, LLC (“MMW”), and MCC’s subsidiary RICHMAC Funding LLC (“RICHMAC”), (collectively referred to as the “Company”). The accompanying unaudited condensed consolidated balance sheet of the Company as of December 31, 2017, which has been derived from audited financial statements, and unaudited condensed consolidated financial statements of the Company as of September 30, 2018 and for the three and nine months ended September 30, 2018 and 2017, were prepared in accordance with the instructions for Form 10‑Q and Article 10 of Regulation S-X and, therefore, do not include information or footnotes necessary for a complete presentation of financial position, results of operations and cash flows in conformity with accounting principles generally accepted in the United States of America. Accordingly, these condensed financial statements should be read in conjunction with the audited financial statements and notes thereto of the Company as of and for the year ended December 31, 2017 in its Annual Report on Form 10-K. Reference is made to the accounting policies of the Company described in the Notes to the Financial Statements contained in the Annual Report on Form 10-K. In the opinion of management, all adjustments (consisting only of normal recurring adjustments) which are necessary for a fair presentation of the unaudited financial statements have been included to present fairly the financial position as of September 30, 2018 and the results of operations for the three and nine months ended September 30, 2018 and 2017, and cash flows for the nine months ended September 30, 2018 and 2017. All interim amounts have not been audited and the results of operations for the three and nine months ended September 30, 2018, herein are not necessarily indicative of the results of operations to be expected for the entire year.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements as of and for the period ended September 30, 2018 include the Company, and its wholly owned subsidiaries, the Bank, and Joy State Bank (prior to it being renamed Farmers-Merchants Bank of Illinois, effective October 22, 2018). Also included are the Bank’s wholly owned subsidiaries, MCC, MCC’s wholly owned subsidiary, RICHMAC, Ash Realty, NMF, and MMW. The consolidated financial statements as of and for the period ended September 30, 2017, include the Company and its wholly owned subsidiary, the Bank, and the Bank’s wholly owned subsidiaries, MCC, MCC’s wholly owned subsidiary, RICHMAC as of August 15, 2017, Ash Realty, NMF, and MMW. All significant intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses, loan servicing rights and fair values of financial instruments.
Reclassifications	Reclassifications Certain reclassifications have been made to the 2017 financial statements to conform to the financial statement presentation as of and for the three and nine months ended September 30, 2018. These reclassifications had no effect net income.