Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Description of the Business Federal Signal Corporation was founded in 1901 and was reincorporated as a Delaware corporation in 1969. References herein to the “Company,” “we,” “our” or “us” refer collectively to Federal Signal Corporation and its subsidiaries. Products manufactured and supplied, and services rendered by the Company are divided into two major operating segments: the Environmental Solutions Group and the Safety and Security Systems Group. The individual operating businesses are organized as such because they share certain characteristics, including technology, marketing, distribution and product application, which create long-term synergies. The Company’s reportable segments are consistent with its operating segments. These segments are discussed in Note 11 – Segment Information. Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries included herein and have been prepared by the Company pursuant to the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to such rules and regulations, although the Company believes that the disclosures are adequate to ensure the information presented is not misleading. These condensed consolidated financial statements have been prepared in accordance with the Company’s accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, and should be read in conjunction with those consolidated financial statements and the notes thereto. As discussed in Note 2 – Acquisitions, on June 2, 2017, the Company completed the acquisition of all of the outstanding shares of capital stock of GenNx/TBEI Intermediate Co., a Delaware corporation (“TBEI”). TBEI is a leading U.S. manufacturer of dump truck bodies and trailers serving maintenance and infrastructure end-markets. The Condensed Consolidated Balance Sheet as of September 30, 2017 includes preliminary fair values assigned to the assets acquired and liabilities assumed in connection with the acquisition, whereas the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2017 include the post-acquisition operating results of TBEI. These condensed consolidated financial statements include all normal and recurring adjustments that we considered necessary to present a fair statement of our results of operations, financial condition and cash flow. Intercompany balances and transactions have been eliminated in consolidation. The results reported in these condensed consolidated financial statements should not be regarded as necessarily indicative of results that may be expected for the entire year. While we label our quarterly information using a calendar convention whereby our first, second and third quarters are labeled as ending on March 31, June 30 and September 30, respectively, it is our longstanding practice to establish interim quarterly closing dates based on a 13-week period ending on a Saturday, with our fiscal year ending on December 31. The effects of this practice are not material and exist only within a reporting year. Recent Accounting Pronouncements and Accounting Changes In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition. This ASU is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The ASU allows either a “full retrospective” adoption, in which the standard is applied to all periods presented in the financial statements, or a “modified retrospective” adoption, in which the guidance is applied retrospectively only to the most current period presented in the financial statements, with the cumulative effect of initially applying the new standard being recognized as an adjustment to the opening balance of retained earnings at the date of initial application. As originally proposed, this guidance was effective for annual reporting periods beginning on or after December 15, 2016, including interim periods within that reporting period, and early adoption was not permitted. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of the new revenue recognition requirements to annual reporting periods beginning on or after December 15, 2017, including interim periods within that reporting period. Under ASU 2015-14, companies are permitted to adopt the guidance early, but no earlier than the original effective date outlined in ASU 2014-09. The FASB has issued a number of amendments to ASU 2014-09 that are intended to address implementation issues that were raised by stakeholders and provide additional practical expedients to reduce the cost and complexity of applying the new revenue standard. These amendments have the same effective date as ASU 2014-09. The new revenue standard will be effective for the Company beginning January 1, 2018, and we expect to apply the “modified retrospective” method of adoption. In preparation for the adoption of the new standard, the Company has established a project management team responsible for analyzing the impact of ASU 2014-09, and the related amendments, across all revenue streams. The project management team is currently reviewing current accounting policies and practices, including a representative sample of contracts with customers, to identify potential differences that would result from applying the requirements under the new standard. In addition, the Company is in the process of designing and implementing the appropriate controls over gathering and reporting the information required to support the expanded disclosure requirements. The Company’s revenue is primarily generated from the sale of finished products to customers. Those sales predominantly contain a single delivery element and revenue is recognized at a single point in time when ownership, risks and benefits transfer. The timing of revenue recognition for these transactions is not expected to be significantly impacted by the new standard. While the Company has not yet finalized its assessment of the impact of the new standard and is in the process of analyzing accounting policies and contracts for its recent acquisition, based on the analysis completed to date, the Company does not expect that the adoption of the revised guidance will have a material impact on its financial position, results of operations, or cash flows. We anticipate the primary impact to be the additional required disclosures around revenue recognition in the notes to the consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which requires organizations that are lessees in operating leases to recognize right-of-use assets and lease liabilities on the balance sheet and requires disclosure of key qualitative and quantitative information about leasing agreements by both lessors and lessees. For a lease to meet the requirements for accounting under a sale-leaseback transaction, it must meet the criteria for a sale in ASC 606, Revenue from Contracts with Customers. Entities are required to recognize and measure operating leases at the beginning of the earliest period presented using a modified retrospective approach. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this guidance will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Payments, which provides additional guidance on the financial statement presentation of certain activities in the statement of cash flows. The activities addressed by this guidance that may be relevant to the Company include cash payments for debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims and proceeds from the settlement of corporate-owned life insurance policies, and the application of the predominance principle. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The amendments in this ASU should be applied using a retrospective transition method to each period presented. If it is impracticable to apply the amendments retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its historical cash flow presentation. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory. This guidance requires the income tax consequences of an intra-entity transfer of an asset other than inventory to be recognized when the transfer occurs, instead of when the asset is sold to an outside party. The pronouncement is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods, with early adoption permitted. The amendments in this ASU should be applied on a modified retrospective basis, with an adjustment reflecting the cumulative effect of adoption being recorded directly to retained earnings as of the beginning of the period of adoption. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment, which eliminates Step 2 from the goodwill impairment test. An entity will therefore perform the goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and recognize an impairment charge for the amount by which the carrying amount exceeds the fair value, not to exceed the total amount of goodwill allocated to the reporting unit. An entity still has the option to perform a qualitative assessment to determine if the quantitative impairment test is necessary. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019 on a prospective basis, with early adoption permitted. The Company currently expects to adopt this guidance effective in the fourth quarter of 2017 and does not expect adoption of this guidance to have a material impact on its consolidated financial statements. In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. This guidance requires that only the service cost component be included on the same line as other compensation costs on the statements of operations. All other components of net periodic pension cost should be reported separately from the service cost component and outside a subtotal of operating income. The guidance also specifies that only the service cost component of net periodic pension cost is eligible for capitalization. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The amendments related to the presentation of the service cost and other components of net periodic pension cost included in this ASU should be applied retrospectively, whereas the amendments relating to the capitalization of the service cost component of net periodic pension cost should be applied prospectively. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities, which intends to better align risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. The amendments also make certain targeted improvements to simplify the application of the hedge accounting guidance by easing certain documentation and assessment requirements. ASU 2017-12 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The amendments in this ASU should be applied on a modified retrospective or prospective basis, depending on the area covered by the update. The Company currently expects to adopt this guidance effective in the fourth quarter of 2017 and does not expect that its adoption will have a material impact on its consolidated financial statements. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and (iii) the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions are used for, but are not limited to, revenue recognition, workers’ compensation and product liability reserves, asset impairment, pension and other post-retirement benefit obligations, income tax contingency accruals and valuation allowances, and litigation-related accruals. Actual results could differ from those estimates. As described in Note 2 – Acquisitions, amounts allocated to certain assets acquired and liabilities assumed in connection with current-year acquisitions are considered preliminary as of September 30, 2017 and are subject to change during the measurement period. Significant Accounting Policies There have been no changes to the Company’s significant accounting policies as disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Organization and Description of the Business

Federal Signal Corporation was founded in 1901 and was reincorporated as a Delaware corporation in 1969. References herein to the “Company,” “we,” “our” or “us” refer collectively to Federal Signal Corporation and its subsidiaries.

Products manufactured and supplied, and services rendered by the Company are divided into two major operating segments: the Environmental Solutions Group and the Safety and Security Systems Group. The individual operating businesses are organized as such because they share certain characteristics, including technology, marketing, distribution and product application, which create long-term synergies. The Company’s reportable segments are consistent with its operating segments. These segments are discussed in Note 11 – Segment Information.

Basis of Presentation and Consolidation

The accompanying unaudited condensed consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries included herein and have been prepared by the Company pursuant to the rules and regulations of the United States (“U.S.”) Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to such rules and regulations, although the Company believes that the disclosures are adequate to ensure the information presented is not misleading. These condensed consolidated financial statements have been prepared in accordance with the Company’s accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, and should be read in conjunction with those consolidated financial statements and the notes thereto.

As discussed in Note 2 – Acquisitions, on June 2, 2017, the Company completed the acquisition of all of the outstanding shares of capital stock of GenNx/TBEI Intermediate Co., a Delaware corporation (“TBEI”). TBEI is a leading U.S. manufacturer of dump truck bodies and trailers serving maintenance and infrastructure end-markets. The Condensed Consolidated Balance Sheet as of September 30, 2017 includes preliminary fair values assigned to the assets acquired and liabilities assumed in connection with the acquisition, whereas the Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2017 include the post-acquisition operating results of TBEI.

These condensed consolidated financial statements include all normal and recurring adjustments that we considered necessary to present a fair statement of our results of operations, financial condition and cash flow. Intercompany balances and transactions have been eliminated in consolidation.

The results reported in these condensed consolidated financial statements should not be regarded as necessarily indicative of results that may be expected for the entire year. While we label our quarterly information using a calendar convention whereby our first, second and third quarters are labeled as ending on March 31, June 30 and September 30, respectively, it is our longstanding practice to establish interim quarterly closing dates based on a 13-week period ending on a Saturday, with our fiscal year ending on December 31. The effects of this practice are not material and exist only within a reporting year.

Recent Accounting Pronouncements and Accounting Changes

In May 2014, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606), which supersedes the revenue recognition requirements in Accounting Standards Codification (“ASC”) 605, Revenue Recognition. This ASU is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. The ASU allows either a “full retrospective” adoption, in which the standard is applied to all periods presented in the financial statements, or a “modified retrospective” adoption, in which the guidance is applied retrospectively only to the most current period presented in the financial statements, with the cumulative effect of initially applying the new standard being recognized as an adjustment to the opening balance of retained earnings at the date of initial application. As originally proposed, this guidance was effective for annual reporting periods beginning on or after December 15, 2016, including interim periods within that reporting period, and early adoption was not permitted. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of the new revenue recognition requirements to annual reporting periods beginning on or after December 15, 2017, including interim periods within that reporting period. Under ASU 2015-14, companies are permitted to adopt the guidance early, but no earlier than the original effective date outlined in ASU 2014-09. The FASB has issued a number of amendments to ASU 2014-09 that are intended to address implementation issues that were raised by stakeholders and provide additional practical expedients to reduce the cost and complexity of applying the new revenue standard. These amendments have the same effective date as ASU 2014-09.

The new revenue standard will be effective for the Company beginning January 1, 2018, and we expect to apply the “modified retrospective” method of adoption. In preparation for the adoption of the new standard, the Company has established a project management team responsible for analyzing the impact of ASU 2014-09, and the related amendments, across all revenue streams. The project management team is currently reviewing current accounting policies and practices, including a representative sample of contracts with customers, to identify potential differences that would result from applying the requirements under the new standard. In addition, the Company is in the process of designing and implementing the appropriate controls over gathering and reporting the information required to support the expanded disclosure requirements. The Company’s revenue is primarily generated from the sale of finished products to customers. Those sales predominantly contain a single delivery element and revenue is recognized at a single point in time when ownership, risks and benefits transfer. The timing of revenue recognition for these transactions is not expected to be significantly impacted by the new standard. While the Company has not yet finalized its assessment of the impact of the new standard and is in the process of analyzing accounting policies and contracts for its recent acquisition, based on the analysis completed to date, the Company does not expect that the adoption of the revised guidance will have a material impact on its financial position, results of operations, or cash flows. We anticipate the primary impact to be the additional required disclosures around revenue recognition in the notes to the consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), which requires organizations that are lessees in operating leases to recognize right-of-use assets and lease liabilities on the balance sheet and requires disclosure of key qualitative and quantitative information about leasing agreements by both lessors and lessees. For a lease to meet the requirements for accounting under a sale-leaseback transaction, it must meet the criteria for a sale in ASC 606, Revenue from Contracts with Customers. Entities are required to recognize and measure operating leases at the beginning of the earliest period presented using a modified retrospective approach. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this guidance will have on its consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Payments, which provides additional guidance on the financial statement presentation of certain activities in the statement of cash flows. The activities addressed by this guidance that may be relevant to the Company include cash payments for debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims and proceeds from the settlement of corporate-owned life insurance policies, and the application of the predominance principle. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The amendments in this ASU should be applied using a retrospective transition method to each period presented. If it is impracticable to apply the amendments retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its historical cash flow presentation.

In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory. This guidance requires the income tax consequences of an intra-entity transfer of an asset other than inventory to be recognized when the transfer occurs, instead of when the asset is sold to an outside party. The pronouncement is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual reporting periods, with early adoption permitted. The amendments in this ASU should be applied on a modified retrospective basis, with an adjustment reflecting the cumulative effect of adoption being recorded directly to retained earnings as of the beginning of the period of adoption. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its consolidated financial statements.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment, which eliminates Step 2 from the goodwill impairment test. An entity will therefore perform the goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and recognize an impairment charge for the amount by which the carrying amount exceeds the fair value, not to exceed the total amount of goodwill allocated to the reporting unit. An entity still has the option to perform a qualitative assessment to determine if the quantitative impairment test is necessary. ASU 2017-04 is effective for fiscal years beginning after December 15, 2019 on a prospective basis, with early adoption permitted. The Company currently expects to adopt this guidance effective in the fourth quarter of 2017 and does not expect adoption of this guidance to have a material impact on its consolidated financial statements.

In March 2017, the FASB issued ASU No. 2017-07, Compensation – Retirement Benefits (Topic 715), Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. This guidance requires that only the service cost component be included on the same line as other compensation costs on the statements of operations. All other components of net periodic pension cost should be reported separately from the service cost component and outside a subtotal of operating income. The guidance also specifies that only the service cost component of net periodic pension cost is eligible for capitalization. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. The amendments related to the presentation of the service cost and other components of net periodic pension cost included in this ASU should be applied retrospectively, whereas the amendments relating to the capitalization of the service cost component of net periodic pension cost should be applied prospectively. The Company currently expects to adopt this guidance effective January 1, 2018 and does not expect that its adoption will have a material impact on its consolidated financial statements.

In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities, which intends to better align risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and presentation of hedge results. The amendments also make certain targeted improvements to simplify the application of the hedge accounting guidance by easing certain documentation and assessment requirements. ASU 2017-12 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The amendments in this ASU should be applied on a modified retrospective or prospective basis, depending on the area covered by the update. The Company currently expects to adopt this guidance effective in the fourth quarter of 2017 and does not expect that its adoption will have a material impact on its consolidated financial statements.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities, (ii) the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and (iii) the reported amounts of revenues and expenses during the reporting period. Significant estimates and assumptions are used for, but are not limited to, revenue recognition, workers’ compensation and product liability reserves, asset impairment, pension and other post-retirement benefit obligations, income tax contingency accruals and valuation allowances, and litigation-related accruals. Actual results could differ from those estimates.

As described in Note 2 – Acquisitions, amounts allocated to certain assets acquired and liabilities assumed in connection with current-year acquisitions are considered preliminary as of September 30, 2017 and are subject to change during the measurement period.

Significant Accounting Policies

There have been no changes to the Company’s significant accounting policies as disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.