Nature of Operations and Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2016
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”), First Business Bank – Milwaukee (“FBB – Milwaukee”) and Alterra Bank (“Alterra”), have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB, FBB – Milwaukee and Alterra 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 Northeast 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, with a loan production office in Kenosha, Wisconsin. Alterra operates as a commercial banking institution in the Kansas City market 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 wholly owned subsidiaries: First Business Capital Corp. (“FBCC”), First Madison Investment Corp. (“FMIC”), First Business Equipment Finance, LLC (“FBEF”), Rimrock Road Investment Fund, LLC (“Rimrock Road”), BOC Investment, LLC (“BOC”) and Mitchell Street Apartments Investments, LLC (“Mitchell Street”). 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 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, 2015. 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 significantly change in the near-term include the value of lease residuals, property under operating leases, securities, income taxes, goodwill and the level of the allowance for loan and lease losses. The results of operations for the nine month period ended September 30, 2016 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2016. 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 unaudited 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, 2015 except as described further below in this Note 1. Recent Accounting Pronouncements In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230). The ASU provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The ASU is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The amendments in this update will be applied retrospectively to each prior period presented. The Corporation intends to adopt the accounting standard during the first quarter of 2018, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity.

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”), First Business Bank – Milwaukee (“FBB – Milwaukee”) and Alterra Bank (“Alterra”), have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB, FBB – Milwaukee and Alterra 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 Northeast 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, with a loan production office in Kenosha, Wisconsin. Alterra operates as a commercial banking institution in the Kansas City market 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 wholly owned subsidiaries: First Business Capital Corp. (“FBCC”), First Madison Investment Corp. (“FMIC”), First Business Equipment Finance, LLC (“FBEF”), Rimrock Road Investment Fund, LLC (“Rimrock Road”), BOC Investment, LLC (“BOC”) and Mitchell Street Apartments Investments, LLC (“Mitchell Street”). 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 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, 2015. 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 significantly change in the near-term include the value of lease residuals, property under operating leases, securities, income taxes, goodwill and the level of the allowance for loan and lease losses. The results of operations for the nine month period ended September 30, 2016 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2016. 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 unaudited 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, 2015 except as described further below in this Note 1.

Recent Accounting Pronouncements

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230). The ASU provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The ASU is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The amendments in this update will be applied retrospectively to each prior period presented. The Corporation intends to adopt the accounting standard during the first quarter of 2018, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity.