Nature of Operations and Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2014
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. The accounting and reporting practices of First Business Financial Services, Inc. (the “Corporation”), its wholly-owned subsidiaries, First Business Bank (“FBB”) and First Business Bank – Milwaukee (“FBB – Milwaukee”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB and FBB – Milwaukee are sometimes referred to together as the “Banks.” FBB operates as a commercial banking institution in the Madison, Wisconsin market, consisting primarily of Dane County and the surrounding areas, 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 the Milwaukee, Wisconsin market, consisting primarily of Waukesha County and the surrounding areas. 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 (“FBEF”) 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”). Basis of Presentation. The accompanying unaudited Consolidated Financial Statements were prepared in accordance with 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 and should be read in conjunction with the Corporation's Consolidated Financial Statements and footnotes thereto included in the Corporation's Annual Report on Form 10-K for the year ended December 31, 2013. The unaudited Consolidated Financial Statements include the accounts of the Corporation and its wholly-owned subsidiaries. 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 have been eliminated in consolidation. Management of the Corporation is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as reported amounts of revenues and expenses during the reporting period. Actual results could differ significantly from those estimates. Material estimates that could experience significant changes in the near-term include the value of foreclosed property, lease residuals, property under operating leases, securities, income taxes and the level of the allowance for loan and lease losses. The results of operations for the three-month period ended March 31, 2014 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2014. Certain amounts in prior periods may have been reclassified to conform to the current presentation. Subsequent events have been evaluated through the date of the issuance of the Consolidated Financial Statements. No significant subsequent events have occurred through this date requiring adjustment to the financial statements or disclosures. 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, 2013 except as described further below in this Note 1. Recent Accounting Pronouncements. In July 2013, the FASB issued ASU No. 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exits.” This ASU provides that an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except to the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date to settle any additional income taxes that would result from disallowance of a tax position, or the tax law does not require the entity to use, and the entity does not intend to use the deferred tax asset for such purpose. In these cases, the unrecognized tax benefit should be presented as a liability. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this standard did not have a material impact on the Corporation’s consolidated financial position or results of operations. In January 2014, the FASB issued ASU No. 2014-04, “Receivables—Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure (a consensus of the FASB Emerging Issues Task Force).” This ASU clarifies that an in-substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar agreement. In addition, the amendments require interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure in accordance with local requirements of the applicable jurisdiction. This amendment is effective for fiscal years, and interim periods within those years, beginning after December 15, 2014. An entity can elect to adopt the amendments using either a modified retrospective method or a prospective transition method. Early adoption is permitted. The Corporation is in the process of evaluating the impact of this standard but does not expect this standard to have a material impact on the Corporation’s consolidated financial position or results of operations.

Nature of Operations and Summary of Significant Accounting Policies

Nature of Operations. The accounting and reporting practices of First Business Financial Services, Inc. (the “Corporation”), its wholly-owned subsidiaries, First Business Bank (“FBB”) and First Business Bank – Milwaukee (“FBB – Milwaukee”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB and FBB – Milwaukee are sometimes referred to together as the “Banks.” FBB operates as a commercial banking institution in the Madison, Wisconsin market, consisting primarily of Dane County and the surrounding areas, 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 the Milwaukee, Wisconsin market, consisting primarily of Waukesha County and the surrounding areas. 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 (“FBEF”) 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”).

Basis of Presentation. The accompanying unaudited Consolidated Financial Statements were prepared in accordance with 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 and should be read in conjunction with the Corporation's Consolidated Financial Statements and footnotes thereto included in the Corporation's Annual Report on Form 10-K for the year ended December 31, 2013. The unaudited Consolidated Financial Statements include the accounts of the Corporation and its wholly-owned subsidiaries. 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 have been eliminated in consolidation.

Management of the Corporation is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements as well as reported amounts of revenues and expenses during the reporting period. Actual results could differ significantly from those estimates. Material estimates that could experience significant changes in the near-term include the value of foreclosed property, lease residuals, property under operating leases, securities, income taxes and the level of the allowance for loan and lease losses. The results of operations for the three-month period ended March 31, 2014 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2014. Certain amounts in prior periods may have been reclassified to conform to the current presentation. Subsequent events have been evaluated through the date of the issuance of the Consolidated Financial Statements. No significant subsequent events have occurred through this date requiring adjustment to the financial statements or disclosures.

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, 2013 except as described further below in this Note 1.

Recent Accounting Pronouncements.

In July 2013, the FASB issued ASU No. 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exits.” This ASU provides that an unrecognized tax benefit, or a portion thereof, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except to the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date to settle any additional income taxes that would result from disallowance of a tax position, or the tax law does not require the entity to use, and the entity does not intend to use the deferred tax asset for such purpose. In these cases, the unrecognized tax benefit should be presented as a liability. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. The adoption of this standard did not have a material impact on the Corporation’s consolidated financial position or results of operations.

In January 2014, the FASB issued ASU No. 2014-04, “Receivables—Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure (a consensus of the FASB Emerging Issues Task Force).” This ASU clarifies that an in-substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar agreement. In addition, the amendments require interim and annual disclosure of both the amount of foreclosed residential real estate property held by the creditor and the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure in accordance with local requirements of the applicable jurisdiction. This amendment is effective for fiscal years, and interim periods within those years, beginning after December 15, 2014. An entity can elect to adopt the amendments using either a modified retrospective method or a prospective transition method. Early adoption is permitted. The Corporation is in the process of evaluating the impact of this standard but does not expect this standard to have a material impact on the Corporation’s consolidated financial position or results of operations.