Nature of Operations and Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Summary of Significant Accounting Policies	Nature of Operations and Summary of Significant Accounting Policies Nature of Operations. First Business Financial Services, Inc. (together with all of its subsidiaries, collectively referred to as “FBFS” or the “Corporation”) is a registered bank holding company incorporated under the laws of the State of Wisconsin and is engaged in the commercial banking business through its wholly owned subsidiaries First Business Bank (“FBB”) and First Business Bank — Milwaukee (“FBB-Milwaukee”). FBB and FBB-Milwaukee are sometimes referred to together as the “Banks”. FBB operates as a commercial banking institution in the Dane County and surrounding areas market with loan production offices in Oshkosh, Appleton, and Green Bay, Wisconsin. FBB also offers trust and investment services through First Business Trust & Investments (“FBTI”), a division of FBB. FBB — Milwaukee operates as a commercial banking institution in Waukesha County and surrounding areas market. The Banks provide a full range of financial services to businesses, business owners, executives, professionals and high net worth individuals. The Banks are subject to competition from other financial institutions and service providers and are also subject to state and federal regulations. FBB has the following subsidiaries: First Business Capital Corp. (“FBCC”), First Madison Investment Corp. (“FMIC”), First Business Equipment Finance, LLC and FBB Real Estate, LLC (“FBBRE”). FMIC is located in and was formed under the laws of the state of Nevada. FBB-Milwaukee has one subsidiary, FBB — Milwaukee Real Estate, LLC (“FBBMRE”). Principles of Consolidation. The unaudited consolidated financial statements include the accounts and results of First Business Financial Services, Inc. (“FBFS” or the “Corporation”), and its wholly-owned subsidiaries, First Business Bank and First Business Bank — Milwaukee (“Banks”). In accordance with the provisions of Accounting Standards Codification (ASC) Topic 810, the Corporation’s ownership interest in FBFS Statutory Trust II (“Trust II”) has not been consolidated into the financial statements. All significant intercompany balances and transactions were eliminated in consolidation. Basis of Presentation. The accompanying unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The Corporation has not changed its significant accounting and reporting policies from those disclosed in the Corporation’s Form 10-K for the year ended December 31, 2011 except as described further below in Note 1. In the opinion of management, all adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the unaudited consolidated financial statements were included in the unaudited consolidated financial statements. The results of operations for the three and six month periods ended June 30, 2012 is not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2012. Certain amounts in prior periods may have been reclassified to conform to the current presentation. Subsequent events were evaluated through the issuance of the unaudited consolidated financial statements. Recent Accounting Pronouncements. Fair Value Measurement. In May 2011, the FASB issued ASU 2011-04, “Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in the U.S. GAAP and IFRSs” (ASU 2011-04). The amended guidance of ASU 2011-04 (i) clarifies how a principal market is determined, (ii) establishes the valuation premise for the highest and best use of non-financial assets, (iii) addresses the fair value measurement of instruments with offsetting market or counterparty credit risks, (iv) extends the prohibition on blockage factors to all three levels of the fair value hierarchy, and (v) requires additional disclosures including transfers between Level 1 and Level 2 of the fair value hierarchy, quantitative and qualitative information and a description of an entity's valuation process for Level 3 fair value measurements, and fair value hierarchy disclosures for financial instruments not measured at fair value. ASU 2011-04 is effective for interim and annual periods beginning on or after December 15, 2011, with early adoption prohibited. The adoption of ASU 2011-04 as of January 1, 2012 did not have a material impact on the Corporation's consolidated financial condition or results of operations.

Nature of Operations and Summary of Significant Accounting Policies

Nature of Operations. First Business Financial Services, Inc. (together with all of its subsidiaries, collectively referred to as “FBFS” or the “Corporation”) is a registered bank holding company incorporated under the laws of the State of Wisconsin and is engaged in the commercial banking business through its wholly owned subsidiaries First Business Bank (“FBB”) and First Business Bank — Milwaukee (“FBB-Milwaukee”). FBB and FBB-Milwaukee are sometimes referred to together as the “Banks”. FBB operates as a commercial banking institution in the Dane County and surrounding areas market with loan production offices in Oshkosh, Appleton, and Green Bay, Wisconsin. FBB also offers trust and investment services through First Business Trust & Investments (“FBTI”), a division of FBB. FBB — Milwaukee operates as a commercial banking institution in Waukesha County and surrounding areas market. The Banks provide a full range of financial services to businesses, business owners, executives, professionals and high net worth individuals. The Banks are subject to competition from other financial institutions and service providers and are also subject to state and federal regulations. FBB has the following subsidiaries: First Business Capital Corp. (“FBCC”), First Madison Investment Corp. (“FMIC”), First Business Equipment Finance, LLC and FBB Real Estate, LLC (“FBBRE”). FMIC is located in and was formed under the laws of the state of Nevada. FBB-Milwaukee has one subsidiary, FBB — Milwaukee Real Estate, LLC (“FBBMRE”).

Principles of Consolidation. The unaudited consolidated financial statements include the accounts and results of First Business Financial Services, Inc. (“FBFS” or the “Corporation”), and its wholly-owned subsidiaries, First Business Bank and First Business Bank — Milwaukee (“Banks”). In accordance with the provisions of Accounting Standards Codification (ASC) Topic 810, the Corporation’s ownership interest in FBFS Statutory Trust II (“Trust II”) has not been consolidated into the financial statements. All significant intercompany balances and transactions were eliminated in consolidation.

Basis of Presentation. The accompanying unaudited consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The Corporation has not changed its significant accounting and reporting policies from those disclosed in the Corporation’s Form 10-K for the year ended December 31, 2011 except as described further below in Note 1.

In the opinion of management, all adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the unaudited consolidated financial statements were included in the unaudited consolidated financial statements. The results of operations for the three and six month periods ended June 30, 2012 is not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2012. Certain amounts in prior periods may have been reclassified to conform to the current presentation. Subsequent events were evaluated through the issuance of the unaudited consolidated financial statements.

Recent Accounting Pronouncements.

Fair Value Measurement. In May 2011, the FASB issued ASU 2011-04, “Fair Value Measurement: Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in the U.S. GAAP and IFRSs” (ASU 2011-04). The amended guidance of ASU 2011-04 (i) clarifies how a principal market is determined, (ii) establishes the valuation premise for the highest and best use of non-financial assets, (iii) addresses the fair value measurement of instruments with offsetting market or counterparty credit risks, (iv) extends the prohibition on blockage factors to all three levels of the fair value hierarchy, and (v) requires additional disclosures including transfers between Level 1 and Level 2 of the fair value hierarchy, quantitative and qualitative information and a description of an entity's valuation process for Level 3 fair value measurements, and fair value hierarchy disclosures for financial instruments not measured at fair value. ASU 2011-04 is effective for interim and annual periods beginning on or after December 15, 2011, with early adoption prohibited. The adoption of ASU 2011-04 as of January 1, 2012 did not have a material impact on the Corporation's consolidated financial condition or results of operations.