Organization and Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2025
Accounting Policies [Abstract]
Nature of Operations	The consolidated financial statements include the accounts of FirstSun Capital Bancorp (“FirstSun” or “Parent Company”) and its wholly-owned subsidiaries, Sunflower Bank, N.A. (the “Bank” or “Sunflower Bank”), Logia Portfolio Management, LLC (“Logia”), and FEIF Capital Partners, LLC, and have been prepared using U.S. generally accepted accounting principles (“U.S. GAAP”) and prevailing practices in the banking industry. All significant intercompany balances and transactions have been eliminated. These entities are collectively referred to as “our”, “us”, “we”, or “the Company”. These consolidated financial statements in this Quarterly Report on Form 10-Q do not include all of the information and footnotes required by U.S. GAAP for a full year presentation and certain disclosures have been condensed or omitted in accordance with rules and regulations of the SEC. These interim financial statements are unaudited, and include, in our opinion, all adjustments necessary for a fair statement of the results for the periods indicated, which are not necessarily indicative of results which may be expected for the full year. Certain prior period amounts have been reclassified to conform to the current presentation. These unaudited consolidated financial statements and notes should be read in conjunction with FirstSun’s audited consolidated financial statements and footnotes thereto for the year ended December 31, 2024, included in our 2024 Annual Report.
Use of Estimates	The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions based on available information. These estimates and assumptions affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. These estimates are based on historical experience and on various assumptions about the future that are believed to be reasonable based on all available information. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to critical accounting policies. In the event that estimates or assumptions prove to differ from actual results, adjustments are made in subsequent periods to reflect more current information.
Reclassifications	Some items in the prior year financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior years net income or stockholders’ equity.
Accounting Pronouncements Recently Adopted and Recent Accounting Pronouncements Not Yet Adopted	As an “emerging growth company” under Section 107 of the JOBS Act, we can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act for complying with new or revised accounting standards. Therefore, we can delay the adoption of certain accounting standards until those standards would otherwise apply to non-public business entities. We intend to take advantage of the benefits of this extended transition period for an “emerging growth company” for as long as it is available to us. For standards that we have delayed adoption, we may lack comparability to other companies who have adopted such standards. In November of 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. We adopted the amendments in this ASU on January 1, 2024. A description of each business and the methodologies used to measure financial performance is described in Note 13 - Segment Information. Recent Accounting Pronouncements Not Yet Adopted - ASU 2023-06, “Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative.” ASU 2023-06 amends the ASC to incorporate certain disclosure requirements from SEC Release No. 33-10532 - Disclosure Update and Simplification that was issued in 2018. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. ASU 2023-06 is not expected to have a significant impact on our financial statements. ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” ASU 2023-09 requires public business entities to disclose in their rate reconciliation table additional categories of information about federal, state and foreign income taxes and to provide more details about the reconciling items in some categories if items meet a quantitative threshold. ASU 2023-09 also requires all entities to disclose income taxes paid, net of refunds, disaggregated by federal, state and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold, among other things. ASU 2023-09 is effective for us on January 1, 2026, though early adoption is permitted. ASU 2023-09 is not expected to have a significant impact on our financial statements.

Organization and Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2025

The consolidated financial statements include the accounts of FirstSun Capital Bancorp (“FirstSun” or “Parent Company”) and its wholly-owned subsidiaries, Sunflower Bank, N.A. (the “Bank” or “Sunflower Bank”), Logia Portfolio Management, LLC (“Logia”), and FEIF Capital Partners, LLC, and have been prepared using U.S. generally accepted accounting principles (“U.S. GAAP”) and prevailing practices in the banking industry. All significant intercompany balances and transactions have been eliminated. These entities are collectively referred to as “our”, “us”, “we”, or “the Company”.

These consolidated financial statements in this Quarterly Report on Form 10-Q do not include all of the information and footnotes required by U.S. GAAP for a full year presentation and certain disclosures have been condensed or omitted in accordance with rules and regulations of the SEC. These interim financial statements are unaudited, and include, in our opinion, all adjustments necessary for a fair statement of the results for the periods indicated, which are not necessarily indicative of results which may be expected for the full year. Certain prior period amounts have been reclassified to conform to the current presentation. These unaudited consolidated financial statements and notes should be read in conjunction with FirstSun’s audited consolidated financial statements and footnotes thereto for the year ended December 31, 2024, included in our 2024 Annual Report.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions based on available information. These estimates and assumptions affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

These estimates are based on historical experience and on various assumptions about the future that are believed to be reasonable based on all available information. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to critical accounting policies. In the event that estimates or assumptions prove to differ from actual results, adjustments are made in subsequent periods to reflect more current information.

Reclassifications

Some items in the prior year financial statements were reclassified to conform to the current presentation. Reclassifications had no effect on prior years net income or stockholders’ equity.

Accounting Pronouncements Recently Adopted and Recent Accounting Pronouncements Not Yet Adopted

As an “emerging growth company” under Section 107 of the JOBS Act, we can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act for complying with new or revised accounting standards. Therefore, we can delay the adoption of certain accounting standards until those standards would otherwise apply to non-public business entities. We intend to take advantage of the benefits of this extended transition period for an “emerging growth company” for as long as it is available to us. For standards that we have delayed adoption, we may lack comparability to other companies who have adopted such standards.

In November of 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which improves reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. We adopted the amendments in this ASU on January 1, 2024. A description of each business and the methodologies used to measure financial performance is described in Note 13 - Segment Information.

Recent Accounting Pronouncements Not Yet Adopted - ASU 2023-06, “Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative.” ASU 2023-06 amends the ASC to incorporate certain disclosure requirements from SEC Release No. 33-10532 - Disclosure Update and Simplification that was issued in 2018. The effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. ASU 2023-06 is not expected to have a significant impact on our financial statements.

ASU No. 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures.” ASU 2023-09 requires public business entities to disclose in their rate reconciliation table additional categories of information about federal, state and foreign income taxes and to provide more details about the reconciling items in some categories if items meet a quantitative threshold. ASU 2023-09 also requires all entities to disclose income taxes paid, net of refunds, disaggregated by federal, state and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold, among other things. ASU 2023-09 is effective for us on January 1, 2026, though early adoption is permitted. ASU 2023-09 is not expected to have a significant impact on our financial statements.