Nature of Operations and Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2017
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”), through our wholly-owned subsidiary, First Business Bank (“FBB” or the “Bank”), has been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB operates as a commercial banking institution primarily in the Wisconsin and greater Kansas City markets. FBB also offers trust and investment services through First Business Trust & Investments (“FBTI”), a division of FBB. The Bank provides a full range of financial services to businesses, business owners, executives, professionals and high net worth individuals. The Bank is subject to competition from other financial institutions and service providers and is 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”), ABKC Real Estate, LLC (“ABKC”), Rimrock Road Investment Fund, LLC (“Rimrock Road”), BOC Investment, LLC (“BOC”), Mitchell Street Apartments Investment, LLC (“Mitchell Street”) and FBB Tax Credit Investment LLC (“FBB Tax Credit”). FMIC is located in and was formed under the laws of the state of Nevada. 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, 2016. The unaudited Consolidated Financial Statements include the accounts of the Corporation and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. 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. 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 securities, level of the allowance for loan and lease losses, lease residuals, property under operating leases, goodwill, level of the Small Business Administration (“SBA”) recourse reserve and income taxes. The results of operations for the nine month period ended September 30, 2017 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2017. 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, 2016. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” with an original effective date for annual reporting periods beginning after December 15, 2016. The ASU is a converged standard between the FASB and the IASB that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The primary objective of the ASU is revenue recognition that represents the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. In August 2015, the FASB issued ASU No. 2015-14, which defers the effective date of ASU 2014-09 to annual and interim reporting periods in fiscal years beginning after December 15, 2017. Earlier application is permitted only as of annual and interim reporting periods in fiscal years beginning after December 15, 2016. In March 2016, the FASB issued ASU No. 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net.” The ASU intends to improve the operability and understandability of the implementation guidance of ASU 2014-09 on principal versus agent considerations. In April, May and December 2016, the FASB also issued ASU No. 2016-10, No. 2016-12 and No. 2016-20, respectively, related to Topic 606. The amendments do not change the core principles of the previously issued guidance, but instead further clarify and provide implementation guidance for certain aspects of the original ASU. The Corporation intends to adopt the accounting standards during the first quarter of 2018, as required. The Corporation has conducted its initial assessment and evaluated contracts to assess and quantify accounting methodology changes resulting from the adoption of this standard. The adoption of this accounting standard is not expected to have a material impact on the Corporation's consolidated financial statements. The FASB continues to release new accounting guidance related to the adoption of this standard, which could impact the Corporation's initial assessment and may change the conclusions reached as to the application of this new guidance. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” The ASU intends to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities and disclosing key information about leasing arrangements. The ASU will require lessees to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (1) a lease liability, which is a lessees’ obligation to make lease payments arising from a lease, measured on a discounted basis; and (2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. The new lease guidance simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. The Corporation intends to adopt the accounting standard during the first quarter of 2019, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments- Credit Losses (Topic 326).” The ASU replaces the incurred loss impairment methodology for recognizing credit losses with a methodology that reflects all expected credit losses. The ASU also requires consideration of a broader range of information to inform credit loss estimates, including such factors as past events, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, and any other financial asset not excluded from the scope that have the contractual right to receive cash. Entities will apply the amendments in the ASU through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The ASU is effective for public companies for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted as of the fiscal years beginning after December 15, 2018. The Corporation intends to adopt the accounting standard during the first quarter of 2020, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity. In May 2017, the FASB issued ASU No. 2017-09, “Compensation- Stock Compensation (Topic 718).” The ASU provides clarity about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The ASU is effective for all entities for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. 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 its results of operations, financial position and liquidity. In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815).” The ASU intends to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. It also expands and refines hedge accounting for both nonfinancial and financial risk components and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. 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 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”), through our wholly-owned subsidiary, First Business Bank (“FBB” or the “Bank”), has been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”). FBB operates as a commercial banking institution primarily in the Wisconsin and greater Kansas City markets. FBB also offers trust and investment services through First Business Trust & Investments (“FBTI”), a division of FBB. The Bank provides a full range of financial services to businesses, business owners, executives, professionals and high net worth individuals. The Bank is subject to competition from other financial institutions and service providers and is 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”), ABKC Real Estate, LLC (“ABKC”), Rimrock Road Investment Fund, LLC (“Rimrock Road”), BOC Investment, LLC (“BOC”), Mitchell Street Apartments Investment, LLC (“Mitchell Street”) and FBB Tax Credit Investment LLC (“FBB Tax Credit”). FMIC is located in and was formed under the laws of the state of Nevada.

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, 2016. The unaudited Consolidated Financial Statements include the accounts of the Corporation and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. 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.

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 securities, level of the allowance for loan and lease losses, lease residuals, property under operating leases, goodwill, level of the Small Business Administration (“SBA”) recourse reserve and income taxes. The results of operations for the nine month period ended September 30, 2017 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2017. 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, 2016.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606),” with an original effective date for annual reporting periods beginning after December 15, 2016. The ASU is a converged standard between the FASB and the IASB that provides a single comprehensive revenue recognition model for all contracts with customers across transactions and industries. The primary objective of the ASU is revenue recognition that represents the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. In August 2015, the FASB issued ASU No. 2015-14, which defers the effective date of ASU 2014-09 to annual and interim reporting periods in fiscal years beginning after December 15, 2017. Earlier application is permitted only as of annual and interim reporting periods in fiscal years beginning after December 15, 2016. In March 2016, the FASB issued ASU No. 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net.” The ASU intends to improve the operability and understandability of the implementation guidance of ASU 2014-09 on principal versus agent considerations. In April, May and December 2016, the FASB also issued ASU No. 2016-10, No. 2016-12 and No. 2016-20, respectively, related to Topic 606. The amendments do not change the core principles of the previously issued guidance, but instead further clarify and provide implementation guidance for certain aspects of the original ASU. The Corporation intends to adopt the accounting standards during the first quarter of 2018, as required. The Corporation has conducted its initial assessment and evaluated contracts to assess and quantify accounting methodology changes resulting from the adoption of this standard. The adoption of this accounting standard is not expected to have a material impact on the Corporation's consolidated financial statements. The FASB continues to release new accounting guidance related to the adoption of this standard, which could impact the Corporation's initial assessment and may change the conclusions reached as to the application of this new guidance.

In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842).” The ASU intends to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities and disclosing key information about leasing arrangements. The ASU will require lessees to recognize the following for all leases (with the exception of short-term leases) at the commencement date: (1) a lease liability, which is a lessees’ obligation to make lease payments arising from a lease, measured on a discounted basis; and (2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Under the new guidance, lessor accounting is largely unchanged. Certain targeted improvements were made to align, where necessary, lessor accounting with the lessee accounting model and Topic 606, Revenue from Contracts with Customers. The new lease guidance simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, with early adoption permitted. The Corporation intends to adopt the accounting standard during the first quarter of 2019, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity.

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments- Credit Losses (Topic 326).” The ASU replaces the incurred loss impairment methodology for recognizing credit losses with a methodology that reflects all expected credit losses. The ASU also requires consideration of a broader range of information to inform credit loss estimates, including such factors as past events, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance-sheet credit exposures, and any other financial asset not excluded from the scope that have the contractual right to receive cash. Entities will apply the amendments in the ASU through a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The ASU is effective for public companies for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted as of the fiscal years beginning after December 15, 2018. The Corporation intends to adopt the accounting standard during the first quarter of 2020, as required, and is currently evaluating the impact on its results of operations, financial position and liquidity.

In May 2017, the FASB issued ASU No. 2017-09, “Compensation- Stock Compensation (Topic 718).” The ASU provides clarity about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. The ASU is effective for all entities for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. 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 its results of operations, financial position and liquidity.

In August 2017, the FASB issued ASU No. 2017-12, “Derivatives and Hedging (Topic 815).” The ASU intends to better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. It also expands and refines hedge accounting for both nonfinancial and financial risk components and aligns the recognition and presentation of the effects of the hedging instrument and the hedged item. The ASU is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. 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 its results of operations, financial position and liquidity.