Basis of Presentation	6 Months Ended
Jun. 30, 2025
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation General In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly the consolidated balance sheets, statements of income, comprehensive income (loss), changes in stockholders’ equity, and cash flows of Nicolet Bankshares, Inc. (the “Company” or “Nicolet”) and its subsidiaries, as of and for the periods presented, and all such adjustments are of a normal recurring nature. All material intercompany transactions and balances have been eliminated. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the entire year. These interim consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission and, therefore, certain information and footnote disclosures normally presented in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) have been omitted or abbreviated. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. Critical Accounting Policies and Estimates Preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying disclosures. Material estimates may be used in accounting for, among other items, the allowance for credit losses, valuation of loans in acquisition transactions, useful lives for depreciation and amortization, fair value of financial instruments, impairment calculations, valuation of deferred tax assets, uncertain income tax positions, and contingencies. These estimates and assumptions are based on management’s knowledge of historical experience, current information, and other factors deemed to be relevant; accordingly, as this information changes, actual results could differ from those estimates. Factors that may cause sensitivity to the aforementioned estimates include but are not limited to: external market factors such as market interest rates and employment rates, changes to operating policies and procedures, changes in applicable banking or tax regulations, and changes to deferred tax estimates. Nicolet considers accounting estimates to be critical to reported financial results if the accounting estimate requires management to make assumptions about matters that are highly uncertain and different estimates that management reasonably could have used for the accounting estimate in the current period, or changes in the accounting estimate that are reasonably likely to occur from period to period, could have a material impact on the financial statements. The accounting estimate we consider to be critical is the determination of the allowance for credit losses. There have been no material changes or developments with respect to the assumptions or methodologies that the Company uses when applying critical accounting policies and developing critical accounting estimates as disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. Recent Accounting Pronouncements Adopted In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This ASU expands segment disclosure requirements for public entities to include disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss. The updated guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within the fiscal years beginning after December 15, 2024, and did not have a material impact on the consolidated financial statements. See Note 10 for the new interim segment disclosures. Future Accounting Pronouncements 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. The amendments in this ASU require disclosure in the notes to financial statements of specified information about certain expenses, such as employee compensation, depreciation, and intangible asset amortization. The updated guidance is effective for annual reporting periods beginning after December 15, 2026. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this ASU improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the rate reconciliation table, as well as income taxes paid disaggregated by jurisdiction. These expanded disclosures will allow investors to better assess how an entity’s overall operations, including the related tax risks, tax planning, and operational opportunities, affect its income tax rate and prospects for future cash flows. The updated guidance is effective for annual periods beginning after December 15, 2024, and is not expected to have a material impact on the consolidated financial statements. Reclassifications Certain amounts in the 2024 consolidated financial statements have been reclassified to conform to the 2025 presentation, namely Certificates of deposit in other banks has been consolidated into Other investments on the consolidated balance sheets. This reclassification was not material and did not impact any other previously reported financial statement line items.

In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly the consolidated balance sheets, statements of income, comprehensive income (loss), changes in stockholders’ equity, and cash flows of Nicolet Bankshares, Inc. (the “Company” or “Nicolet”) and its subsidiaries, as of and for the periods presented, and all such adjustments are of a normal recurring nature. All material intercompany transactions and balances have been eliminated. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the entire year.

These interim consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission and, therefore, certain information and footnote disclosures normally presented in accordance with generally accepted accounting principles in the United States of America (“U.S. GAAP”) have been omitted or abbreviated. These consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and footnotes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024.

Preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying disclosures. Material estimates may be used in accounting for, among other items, the allowance for credit losses, valuation of loans in acquisition transactions, useful lives for depreciation and amortization, fair value of financial instruments, impairment calculations, valuation of deferred tax assets, uncertain income tax positions, and contingencies. These estimates and assumptions are based on management’s knowledge of historical experience, current information, and other factors deemed to be relevant; accordingly, as this information changes, actual results could differ from those estimates. Factors that may cause sensitivity to the aforementioned estimates include but are not limited to: external market factors such as market interest rates and employment rates, changes to operating policies and procedures, changes in applicable banking or tax regulations, and changes to deferred tax estimates. Nicolet considers accounting estimates to be critical to reported financial results if the accounting estimate requires management to make assumptions about matters that are highly uncertain and different estimates that management reasonably could have used for the accounting estimate in the current period, or changes in the accounting estimate that are reasonably likely to occur from period to period, could have a material impact on the financial statements. The accounting estimate we consider to be critical is the determination of the allowance for credit losses.

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This ASU expands segment disclosure requirements for public entities to include disclosure of significant segment expenses that are regularly provided to the chief operating decision maker and included within each reported measure of segment profit or loss. The updated guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within the fiscal years beginning after December 15, 2024, and did not have a material impact on the consolidated financial statements. See Note 10 for the new interim segment disclosures.

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. The amendments in this ASU require disclosure in the notes to financial statements of specified information about certain expenses, such as employee compensation, depreciation, and intangible asset amortization. The updated guidance is effective for annual reporting periods beginning after December 15, 2026.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this ASU improve the transparency of income tax disclosures by requiring consistent categories and greater disaggregation of information in the rate reconciliation table, as well as income taxes paid disaggregated by jurisdiction. These expanded disclosures will allow investors to better assess how an entity’s overall operations, including the related tax risks, tax planning, and operational opportunities, affect its income tax rate and prospects for future cash flows. The updated guidance is effective for annual periods beginning after December 15, 2024, and is not expected to have a material impact on the consolidated financial statements.

Certain amounts in the 2024 consolidated financial statements have been reclassified to conform to the 2025 presentation, namely Certificates of deposit in other banks has been consolidated into Other investments on the consolidated balance sheets. This reclassification was not material and did not impact any other previously reported financial statement line items.