SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Mar. 31, 2026
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations: Mechanics Bancorp, a Washington corporation (the “Company”), is a financial holding company and primarily operates through 121-year-old Mechanics Bank, its wholly-owned subsidiary. Mechanics Bank is a full-service community bank with 166 branches throughout California, Washington, Oregon and Hawaii. Following the strategic Merger of HomeStreet Bank with and into Mechanics Bank on September 2, 2025, with Mechanics Bank surviving the Merger as a wholly-owned subsidiary of the Company, the assets, liabilities and operations of HomeStreet Bank became the assets, liabilities and operations of Mechanics Bank. Headquartered in Walnut Creek, California, Mechanics Bank provides a wide range of products and services in consumer and business banking, commercial lending, cash management services, private banking, and comprehensive wealth management and trust services. Prior to merging with and into Mechanics Bank on September 2, 2025, HomeStreet Bank was principally engaged in commercial banking, consumer banking, and real estate lending, including construction and permanent loans on commercial real estate and single-family residences. It also sold insurance products for consumer clients. It provided these financial products and services to its customers through bank branches, loan production offices and ATMs, and through online, mobile and telephone banking channels. The Company’s business is conducted primarily through its wholly-owned subsidiaries, Mechanics Bank and HomeStreet Statutory Trusts (I, II, III and IV), as well as Mechanics Bank’s subsidiaries: MacDonald Auxiliary Corporation, Mechanics Real Estate Holdings Inc., 3190 Klose Way, LLC, Hydrox Properties XXVI, LLC, Continental Escrow Company, HS Properties Inc., HS Evergreen Corporate Center LLC, Union Street Holdings LLC, and 16389 Redmond Way LLC. Ceasing the origination of auto loans in February 2023, Mechanics Bank continued to service its existing auto loan portfolio until May 1, 2025, when it entered into a servicing agreement with a third-party servicer to oversee and manage Mechanics Bank’s active portfolio of auto loans. The portfolio consisted of new and pre-owned retail automobile sales contracts purchased from both franchised and independent automobile dealerships in the United States. Basis of Presentation: The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Unless the context requires otherwise, all references to the Company include its wholly-owned subsidiaries. The accounting and reporting policies of the Company are based upon GAAP and conform to predominant practices within the financial services industry. The Merger is considered a reverse acquisition in accordance with ASC 805-40, “Business Combinations-Reverse Acquisitions.” Mechanics Bank is the accounting acquirer (“legal acquiree”), HomeStreet Bank is the accounting acquiree and Mechanics Bancorp, formerly HomeStreet, Inc., is the legal acquirer. Mechanics Bancorp’s financial results for all periods ended prior to September 2, 2025 reflect legacy Mechanics Bank’s results only on a standalone basis. In addition, Mechanics Bancorp’s reported financial results reflect legacy Mechanics Bank’s financial results only on a standalone basis until the closing of the Merger on September 2, 2025 and results of the combined company beginning September 2, 2025. The number of shares issued and outstanding, earnings per share, and all references to share quantities or metrics of Mechanics Bancorp have been retrospectively restated to reflect the equivalent number of shares issued in the Merger since the Merger was accounted for as a reverse acquisition. As the accounting acquirer, Mechanics Bank remeasured the identifiable assets acquired and liabilities assumed in the Merger as of September 2, 2025 at their acquisition date fair values. Refer to Note 2, “Business Combination,” for additional information on the transaction. Certain prior period amounts have been reclassified to conform to the current presentation. These reclassifications had no impact on the Company’s prior year net income or shareholders’ equity. These unaudited interim financial statements reflect all adjustments that are, in the opinion of management, necessary for a fair statement of the results for the periods presented. These adjustments are of a normal recurring nature, unless otherwise disclosed in these accompanying notes to the financial statements. The results of operations in the interim financial statements do not necessarily indicate the results that may be expected for the full year. Certain disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted in the interim financial statements, as permitted under GAAP. The unaudited interim financial statements should be read in conjunction with the Company’s audited Consolidated Financial Statements and Notes to Consolidated Financial Statements for the years ended December 31, 2025 and 2024 included in our 2025 Annual Report on Form 10-K. Use of Estimates: The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and disclosures provided, and actual results could differ. A material estimate that is particularly susceptible to significant change relates to the determination of the allowance for credit losses. Other significant estimates that may be subject to change include fair value determinations and disclosures, evaluation of goodwill and other intangible assets for impairment, and the realization of deferred tax assets. These estimates may be adjusted as more current information becomes available, and any adjustments may be significant. Business Combinations: Purchase accounting requires that the assets purchased, the liabilities assumed, and non-controlling interests all be reported on the acquirer’s financial statements at their fair value, with any excess of purchase consideration over the net assets being reported as goodwill. A bargain purchase gain is realized when the excess of the fair value of identifiable net assets acquired is greater than the consideration paid and it is recognized in earnings on the acquisition date. Merger with HomeStreet: On September 2, 2025, Mechanics Bancorp (formerly known as “HomeStreet, Inc.”), consummated the Merger by and among the Company, HomeStreet Bank, a Washington state-chartered commercial bank and a wholly-owned subsidiary of the Company, and Mechanics Bank. In connection with the Merger, HomeStreet Bank merged with and into Mechanics Bank, with Mechanics Bank surviving the Merger and becoming a wholly-owned subsidiary of the Company. As a result of the Merger, the Company’s business became primarily the business conducted by Mechanics Bank. Immediately following the Merger, (1) legacy Mechanics Bank shareholders owned approximately 91.7% of the Company on an economic basis and 91.3% of the voting power of the Company and (2) legacy Company shareholders owned approximately 8.3% of the Company on an economic basis and 8.7% of the voting power of the Company. See Note 16, “Shareholders’ Equity and Dividend Limitations” for details of the Company’s Class A and Class B common stock, including further information on the economic rights of the Class B shares. The Merger is considered a reverse acquisition. Mechanics Bank is the accounting acquirer (“legal acquiree”), HomeStreet Bank is the accounting acquiree and Mechanics Bancorp is the legal acquirer. As the accounting acquirer, Mechanics Bank remeasured the identifiable assets acquired and liabilities assumed in the Merger at their acquisition date fair values. These estimates are considered preliminary as of March 31, 2026, are subject to change for up to one year after the Merger date, and any changes could be material. Asset Sale: As discussed in Note 17, “Subsequent Events—Asset Sale,” on May 1, 2026, Mechanics Bank completed the previously announced sale of its Fannie Mae Multifamily Delegated Underwriting and Servicing (“DUS®”) business line to Fifth Third for aggregate cash consideration of approximately $126 million. Adoption of Purchased Seasoned Loans Accounting Standard: The Company early adopted Accounting Standards Update (“ASU”) 2025-08, “Financial Instruments–Credit Losses (Topic 326): Purchased Loans,” during the fourth quarter of 2025. This new standard, which the Company elected to early adopt as of January 1, 2025, requires acquired loans that meet certain criteria at acquisition (purchased seasoned loans) to be recognized at their purchase price plus the amount of the allowance for expected credit losses (gross-up approach). As a result, for purchased seasoned loans acquired in the Merger, the Company established an allowance for credit losses of $20.3 million at the date of acquisition for these loans and reversed the provision for credit losses recorded in the third quarter of 2025, and recorded it as part of the acquired loans initial amortized cost basis. Required disclosures regarding the impact of the adoption were presented in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025. In addition, third quarter 2025 results will be retrospectively adjusted when the Company files its Quarterly Report on Form 10-Q for the quarter ended September 30, 2026. Recent Accounting Developments In November 2024, the FASB issued ASU 2024-03, “Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” ASU 2024-03 requires public companies to disclose, in the notes to the financial statements, specific information about certain costs and expenses at each interim and annual reporting period. This includes disclosing amounts related to employee compensation, depreciation, and intangible asset amortization. In addition, public companies will need to provide qualitative description of the amounts remaining in relevant expense captions that are not separately disaggregated quantitatively. ASU 2024-03 is effective for public business entities for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Implementation of ASU 2024-03 may be applied prospectively or retrospectively. In January 2025, the FASB also issued ASU 2025-01, “Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures-Clarifying the Effective Date,” which amends the effective date of ASU 2024-03 to clarify that all public business entities are required to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. The enhanced income statement expense disclosure requirements apply on a prospective basis. However, retrospective application in all prior periods presented is permitted. The Company is currently evaluating the impact of this update on its consolidated financial statements and related disclosures. The adoption of ASU 2024-03 and ASU 2025-01 will not have an impact on the Company’s financial position or results of operations as it impacts disclosures only. We are assessing the impact on our disclosures.