NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES (Policies)	3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation—The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and in accordance with guidance provided by the Securities and Exchange Commission (“SEC”). Accordingly, the condensed consolidated financial statements do not include all the information and footnotes required by GAAP for complete financial statements. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows of the Company on a consolidated basis, and all such adjustments are of a normal recurring nature. Transactions between Stellar and the Bank have been eliminated. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025. Operating results for the three months ended March 31, 2026 are not necessarily indicative of the results that may be expected for the year ending December 31, 2026.
Reclassifications	Reclassifications—Certain items in the prior year's financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior year net income or shareholders’ equity.
Recent Accounting Standards	Recent Accounting Standards Accounting Standards Update (“ASU”) 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” This update requires that public businesses disclose in tabular format, disaggregating information about prescribed categories underlying any relevant income statement expense caption. The prescribed categories include, among other things, employee compensation, depreciation and intangible asset amortization. ASU 2024-03 will be effective for the Company, on a prospective basis, for annual reporting periods beginning after December 15, 2026. Early adoption and retrospective application is permitted. ASU 2024-03 is not expected to have a significant impact on the Company’s financial statements. ASU 2025‑08, “Financial Instruments - Credit Losses (Topic 326): Purchased Loans.” ASU 2025-08 expands the scope of the “gross‑up” method, formerly applicable only to purchased credit‑deteriorated ("PCD") assets, to include acquired non‑PCD loans that meet certain criteria, now referred to as purchased seasoned loans (“PSLs”). Under this model, an allowance for expected credit losses is recognized at acquisition, offsetting the loan’s amortized cost basis, thereby eliminating the day-one credit‑loss expense previously required for non‑PCD assets. PSLs are defined as non‑PCD loans acquired either (i) through a business combination, or (ii) purchased more than 90 days after origination when the acquirer was not involved in origination. ASU 2025-08 will be effective for the Company on a prospective basis for loans acquired on or after the adoption date, for interim and annual reporting periods beginning in 2027, though early adoption is permitted. ASU 2025-08 is not expected to have a significant impact on the Company’s financial statements.

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES (Policies)

3 Months Ended

Mar. 31, 2026

Basis of Presentation—The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and in accordance with guidance provided by the Securities and Exchange Commission (“SEC”). Accordingly, the condensed consolidated financial statements do not include all the information and footnotes required by GAAP for complete financial statements. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.

In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows of the Company on a consolidated basis, and all such adjustments are of a normal recurring nature. Transactions between Stellar and the Bank have been eliminated. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025. Operating results for the three months ended March 31, 2026 are not necessarily indicative of the results that may be expected for the year ending December 31, 2026.

Reclassifications

Reclassifications—Certain items in the prior year's financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior year net income or shareholders’ equity.

Recent Accounting Standards

Accounting Standards Update (“ASU”) 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses.” This update requires that public businesses disclose in tabular format, disaggregating information about prescribed categories underlying any relevant income statement expense caption. The prescribed categories include, among other things, employee compensation, depreciation and intangible asset amortization. ASU 2024-03 will be effective for the Company, on a prospective basis, for annual reporting periods beginning after December 15, 2026. Early adoption and retrospective application is permitted. ASU 2024-03 is not expected to have a significant impact on the Company’s financial statements.

ASU 2025‑08, “Financial Instruments - Credit Losses (Topic 326): Purchased Loans.” ASU 2025-08 expands the scope of the “gross‑up” method, formerly applicable only to purchased credit‑deteriorated ("PCD") assets, to include acquired non‑PCD loans that meet certain criteria, now referred to as purchased seasoned loans (“PSLs”). Under this model, an allowance for expected credit losses is recognized at acquisition, offsetting the loan’s amortized cost basis, thereby eliminating the day-one credit‑loss expense previously required for non‑PCD assets. PSLs are defined as non‑PCD loans acquired either (i) through a business combination, or (ii) purchased more than 90 days after origination when the acquirer was not involved in origination. ASU 2025-08 will be effective for the Company on a prospective basis for loans acquired on or after the adoption date, for interim and annual reporting periods beginning in 2027, though early adoption is permitted. ASU 2025-08 is not expected to have a significant impact on the Company’s financial statements.