Nature of Operations and Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2018
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”), have 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”) and investment portfolio administrative services and asset/liability management services through First Business Consulting Services (“FBCS”), both divisions 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, 2017. 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 and interest rate swaps, 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, 2018 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2018. 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, 2017. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The ASU is a converged standard between the FASB and the International Accounting Standards Board 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. The Corporation adopted ASU 2014-09 and all subsequent amendments to the ASU (collectively, “ASC 606”) in the first quarter of 2018 with no material impact on its results of operations, financial position and liquidity. In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments (Subtopic 825-10).” The ASU amends certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This amendment supersedes the guidance to classify equity securities with readily determinable fair values into different categories, requires equity securities to be measured at fair value with changes in the fair value recognized through net income and simplifies the impairment assessment of equity investments without readily determinable fair values. The amendment requires public business entities that are required to disclose the fair value of financial instruments measured at amortized cost on the balance sheet to measure that fair value using the exit price notion. The amendment requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option. The Corporation adopted the accounting standard during the first quarter of 2018 and modified its fair value disclosure of financial instruments to reflect an exit price notion. The adoption of the standard did not have a material impact on the Corporation’s results of operations, financial position and liquidity. 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) may 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. Lessees and lessors may also elect to 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, 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. The Corporation leases office space, loan production offices and specialty financing production offices under noncancelable operating leases which expire on various dates through 2028. The Corporation also leases office equipment. The implementation efforts are ongoing, including the review of our leases and related accounting policies. Future minimum lease payments associated with 29 noncancelable operating leases as of September 30, 2018 was $10.6 million. The Corporation does not expect the accounting standard to have a material impact on its results of operations and liquidity. The estimated impact on its financial position continues to be refined, which may also change based on decisions to modify or renew leases prior to the implementation date. 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. A cross-functional team has been established and a third-party software solution has been obtained to assist with the implementation of the standard. Management is in the process of gathering necessary data and reviewing potential methods to calculate the expected credit losses. In June 2018, the FASB issued ASU No. 2018-07, “Compensation- Stock Compensation (Topic 718).” The ASU expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. 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. In August 2018, the FASB issued ASU No. 2018-15, “Intangibles-Goodwill and Other Internal-Use Software (Subtopic 350-40).” The ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Implementation costs incurred in the application development stage are capitalized depending on the nature of the costs, while costs incurred during the preliminary project and post implementation stages are expensed as the activities are performed. The amendment also requires entities to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement and in the same income statement line item as the fees associated with the hosting element. The ASU is effective for fiscal years beginning after December 15, 2019, 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”), have 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”) and investment portfolio administrative services and asset/liability management services through First Business Consulting Services (“FBCS”), both divisions 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, 2017. 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 and interest rate swaps, 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, 2018 are not necessarily indicative of results that may be expected for any other interim period or the entire fiscal year ending December 31, 2018. 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, 2017.

Recent Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606).” The ASU is a converged standard between the FASB and the International Accounting Standards Board 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. The Corporation adopted ASU 2014-09 and all subsequent amendments to the ASU (collectively, “ASC 606”) in the first quarter of 2018 with no material impact on its results of operations, financial position and liquidity.

In January 2016, the FASB issued ASU No. 2016-01, “Financial Instruments (Subtopic 825-10).” The ASU amends certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This amendment supersedes the guidance to classify equity securities with readily determinable fair values into different categories, requires equity securities to be measured at fair value with changes in the fair value recognized through net income and simplifies the impairment assessment of equity investments without readily determinable fair values. The amendment requires public business entities that are required to disclose the fair value of financial instruments measured at amortized cost on the balance sheet to measure that fair value using the exit price notion. The amendment requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option. The Corporation adopted the accounting standard during the first quarter of 2018 and modified its fair value disclosure of financial instruments to reflect an exit price notion. The adoption of the standard did not have a material impact on the Corporation’s results of operations, financial position and liquidity.

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) may 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. Lessees and lessors may also elect to 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, 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. The Corporation leases office space, loan production offices and specialty financing production offices under noncancelable operating leases which expire on various dates through 2028. The Corporation also leases office equipment. The implementation efforts are ongoing, including the review of our leases and related accounting policies. Future minimum lease payments associated with 29 noncancelable operating leases as of September 30, 2018 was $10.6 million. The Corporation does not expect the accounting standard to have a material impact on its results of operations and liquidity. The estimated impact on its financial position continues to be refined, which may also change based on decisions to modify or renew leases prior to the implementation date.

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. A cross-functional team has been established and a third-party software solution has been obtained to assist with the implementation of the standard. Management is in the process of gathering necessary data and reviewing potential methods to calculate the expected credit losses.

In June 2018, the FASB issued ASU No. 2018-07, “Compensation- Stock Compensation (Topic 718).” The ASU expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. 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.

In August 2018, the FASB issued ASU No. 2018-15, “Intangibles-Goodwill and Other Internal-Use Software (Subtopic 350-40).” The ASU aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). Implementation costs incurred in the application development stage are capitalized depending on the nature of the costs, while costs incurred during the preliminary project and post implementation stages are expensed as the activities are performed. The amendment also requires entities to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement and in the same income statement line item as the fees associated with the hosting element. The ASU is effective for fiscal years beginning after December 15, 2019, 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.