Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2017
Accounting Policies [Abstract]
Business Description and Basis of Presentation	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 services rendered by the Company are divided into two major operating segments: Environmental Solutions Group and 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. As discussed in Note 15 – Segment Information, the Company’s reportable segments are consistent with its operating segments.
Fiscal period	Our fiscal year ends on December 31. All references to 2017, 2016 and 2015 relate to the fiscal year unless otherwise indicated.
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”). 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 (collectively with its subsidiaries, “TBEI”). TBEI is a leading U.S. manufacturer of dump truck bodies and trailers serving maintenance and infrastructure end-markets. The Consolidated Balance Sheet as of December 31, 2017 includes fair values assigned to the assets acquired and liabilities assumed in connection with the acquisition, whereas the Consolidated Statements of Operations for the year ended December 31, 2017 include the post-acquisition operating results of TBEI. As discussed in Note 8 – Income Taxes, the Tax Cuts and Jobs Act (the “2017 Tax Act”) was enacted on December 22, 2017. The SEC staff has issued Staff Accounting Bulletin No. 118 (“SAB 118”) to provide guidance on the accounting for the tax impact of the 2017 Tax Act. Under SAB 118, a company that has not completed its accounting for the effects of the 2017 Tax Act by its financial reporting deadline may report provisional amounts based on reasonable estimates for items for which the accounting is incomplete. Those amounts will be subject to adjustment during a measurement period of up to one year. The consolidated financial statements for the year ended December 31, 2017 include the Company’s provisional estimates of the impact of the 2017 Tax Act, in accordance with SAB 118. Intercompany balances and transactions have been eliminated in consolidation. In addition, certain prior year amounts have been reclassified to conform to current year presentation.
Non-U.S. Operations	Non-U.S. Operations Assets and liabilities of non-U.S. subsidiaries, other than those whose functional currency is the U.S. dollar, are translated at current exchange rates with the related translation adjustments reported in stockholders’ equity as a component of Accumulated other comprehensive loss. Accounts within the Consolidated Statements of Operations are translated at the average exchange rate during the period. Non-monetary assets and liabilities are translated at historical exchange rates. Relating to transactions that are denominated in a currency other than the functional currency, the Company incurs foreign currency transaction gains or losses, which are recognized in the Consolidated Statements of Operations as a component of Other (income) expense, net. For the year ended December 31, 2017, the Company realized foreign currency transaction gains of $1.3 million, whereas in the years ended December 31, 2016 and 2015, the Company incurred foreign currency transaction losses of $0.1 million and $1.5 million, respectively.
Use of Estimates	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. Actual results could differ from those estimates.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with a maturity of three months or less, when purchased, to be cash equivalents. The carrying amount of cash and cash equivalents approximates fair value because of the short-term maturity and highly liquid nature of these instruments.
Accounts Receivable	Accounts Receivable The Company carries accounts receivable at the face amount less an allowance for doubtful accounts for estimated losses as a result of a customer’s inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends and the time outstanding of specific balances to estimate the amount of accounts receivables that may not be collected in the future and records the appropriate provision.
Inventories	Inventories The Company’s inventories are valued at the lower of cost or market. Cost is determined using the first-in, first-out method. Included in the cost of inventories are raw materials, direct wages and associated production costs.
Properties and Equipment	Properties and Equipment Properties and equipment are stated at cost, net of depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Useful lives generally range from eight to 40 years for buildings and three to 15 years for machinery and equipment. Leasehold improvements are depreciated over the shorter of the remaining life of the lease or the useful life of the improvement. Depreciation expense is primarily included as a component of Cost of sales on the Consolidated Statements of Operations, with depreciation expense associated with certain assets used for administrative purposes being presented within Selling, engineering, general and administrative (“SEG&A”) expenses. Depreciation expense, which includes depreciation on rental equipment, was $25.2 million, $18.9 million and $12.0 million in the years ended December 31, 2017, 2016 and 2015, respectively. Properties and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Rental Equipment The Company enters into lease agreements with customers related to the rental of certain equipment. All of these leasing agreements are classified as operating leases and are for periods generally not to exceed five years. In accounting for these leases, the cost of the equipment purchased or manufactured by the Company is recorded as an asset and is depreciated over its estimated useful life. Rental income is recognized ratably over the term of the underlying leases. Rental equipment is depreciated to an estimated residual value on a straight-line basis over the estimated useful lives of the assets and is reviewed for potential impairment whenever an event occurs or circumstances change that indicate the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares non-discounted cash flows expected to be generated by that asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on a non-discounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary. Rental equipment includes certain equipment that is manufactured by the Company and subsequently transferred to the rental fleet, as well as equipment purchased from third-party manufacturers, for the purpose of renting to end-customers. The related cash flow activity associated with these transactions is reflected within operating activities on the Consolidated Statements of Cash Flows.
Goodwill	Goodwill Goodwill represents the excess of the cost of an acquired business over the amounts assigned to its net assets. Goodwill is not amortized but is tested for impairment at a reporting unit level on an annual basis or when an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company performed its annual goodwill impairment test as of October 31, 2017. In testing the goodwill of its reporting units for potential impairment, the Company applies either a qualitative test, or a two-step quantitative test, in accordance with Accounting Standards Codification (“ASC”) 350, Intangibles — Goodwill and Other. A qualitative approach is applied when the Company concludes that it is not “more likely than not” that the fair value of a reporting unit is less than its carrying value. In this situation, the Company would not be required to perform the two-step impairment test described below. The first step in the quantitative two-step approach is used to identify potential impairment, by comparing the fair value of a reporting unit with its carrying amount, including goodwill. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and the second step of the impairment test is unnecessary. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any. The second step compares the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. If the carrying amount of reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. The Company generally determines the fair value of its reporting units using two valuation methods: the “Income Approach — Discounted Cash Flow Analysis” method, and the “Market Approach — Guideline Public Company Method.” Under the “Income Approach — Discounted Cash Flow Analysis” method, the key assumptions consider projected sales, cost of sales and operating expenses. These assumptions were determined by management utilizing our internal operating plan, including growth rates for revenues and operating expenses and margin assumptions. An additional key assumption under this approach is the discount rate, which is determined by reviewing current risk-free rates of capital and current market interest rates and by evaluating the risk premium relevant to the business segment. If our assumptions relative to growth rates were to change, our fair value calculation may change, which could result in impairment. Under the “Market Approach — Guideline Public Company Method,” the Company identified several publicly traded companies, which we believe have sufficiently relevant similarities to our businesses. For these companies, the Company used market values to calculate the mean ratio of invested capital to revenues and invested capital to EBITDA. Similar to the income approach discussed above, sales, cost of sales, operating expenses and their respective growth rates are key assumptions utilized. The market prices of the Company’s common stock and other guideline companies are additional key inputs. If these market prices increase, the estimated market value would increase. Conversely, if market prices decrease, the estimated market value would decrease. The results of these two methods are weighted based upon management’s evaluation of the relevance of the two approaches. Management used a qualitative approach to assess the goodwill of its reporting units for potential impairment in 2017. The Company concluded that it was not “more likely than not” that the fair value of its reporting units were less than their carrying values. The Company had no goodwill impairments for its continuing operations in 2017, 2016 or 2015. See Note 6 – Goodwill and Other Intangible Assets for a summary of the Company’s goodwill by segment. On January 1, 2018, the Company adopted Accounting Standards Update (“ASU”) No. 2017-04, Intangibles – Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment, which eliminates the second step of the two-step quantitative approach for testing goodwill for potential impairment. See Note 19 - New Accounting Pronouncements (Issued But Not Yet Adopted) for further discussion.
Intangible Assets	Intangible Assets Definite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives and are tested for impairment if indicators exist in a manner similar to that described above for Rental Equipment. Indefinite-lived intangible assets are tested for impairment on an annual basis at year-end, or more frequently if an event occurs or circumstances change that indicate the fair value of an indefinite-lived intangible asset could be below its carrying amount. In testing the indefinite-lived intangibles assets for potential impairment, the Company applies either a qualitative test, or a quantitative test, in accordance with ASC 350, Intangibles — Goodwill and Other. A qualitative approach is applied when the Company concludes that it is not “more likely than not” that the fair value of the indefinite-lived intangibles are less than their carrying value. A quantitative impairment test consists of comparing the fair value of the indefinite-lived intangible asset with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value. Management used a qualitative approach to assess its indefinite-lived intangible assets for potential impairment in 2017 and 2016. The Company concluded that it was not “more likely than not” that the fair value of indefinite-lived intangible assets were less than their carrying values. The Company had no indefinite-lived intangible asset impairments for its continuing operations in 2017 or 2016. See Note 6 – Goodwill and Other Intangible Assets for a summary of the Company’s intangible assets.
Warranty	Warranty Sales of many of the Company’s products carry express warranties based on terms that are generally accepted in the Company’s marketplaces. The Company records provisions for estimated warranty, which are included within Cost of sales, at the time of sale based on historical experience. The Company periodically adjusts these provisions to reflect actual experience. Infrequently, a material warranty issue can arise which is beyond the scope of the Company’s historical experience. The Company records costs related to these issues as they become probable and estimable. The Company also sells optional extended warranty contracts that extend coverage beyond the initial term of the express warranty period. At the time of sale, revenue related to the extended warranty contract is deferred and recognized as income over the life of the contract. As of December 31, 2017 and 2016, deferred revenue associated with extended warranty contracts was $2.9 million and $2.6 million, respectively, and was included within Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Costs under extended warranty contracts are expensed as incurred.
Workers' Compensation and Product Liability Reserves	Workers’ Compensation and Product Liability Reserves Due to the nature of the Company’s manufacturing and products, the Company is subject to claims for workers’ compensation and product liability in the normal course of business. The Company is self-funded for a portion of these claims. The Company establishes a reserve using a third-party actuary for any known outstanding matters, including a reserve for claims incurred but not yet reported. The amount and timing of cash payments relating to these claims are considered to be reliably determinable given the nature of the claims and historical claim volumes to support the actuarial assumptions and judgments used to derive the expected loss payment patterns. As such, the reserves recorded are discounted using a risk-free rate that matches the average duration of the claims. The Company has not established a reserve for potential losses resulting from the firefighter hearing loss litigation, with the exception of certain estimated losses that have been recognized related to settlement discussions (see Note 11 – Legal Proceedings). If the Company is not successful in its defense after exhausting all appellate options, it would record a charge for such claims, to the extent they exceed insurance recoveries, when the related losses become probable and estimable.
Pensions	Pensions The Company sponsors domestic and foreign defined benefit pension plans. Key assumptions used in the accounting for these employee benefit plans include the discount rate, expected long-term rate of return on plan assets and estimates of future mortality of plan participants. The weighted-average discount rate used to measure pension liabilities and costs is selected using a hypothetical portfolio of high-quality bonds that would provide the necessary cash flow to match the projected benefit payments of the plans. The discount rate represents the rate at which our benefit obligations could effectively be settled as of the year-end measurement date. The weighted-average discount rate used to measure pension liabilities decreased from 2016 to 2017. See Note 9 – Pensions for further discussion. The expected long-term rate of return on plan assets is based on historical and expected returns for the asset classes in which the plans are invested. The Company references the most recent mortality tables and scales published by the Society of Actuaries in determining its estimate of future mortality.
Revenue Recognition	Revenue Recognition Net sales consist primarily of revenue from the sale of equipment, environmental vehicles, parts, service and maintenance contracts. The Company recognizes revenue for products when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred, (iii) the sales price is fixed or determinable and (iv) collection is reasonably assured. A product is considered delivered to the customer once it has been shipped, and title and risk of loss have been transferred. For most of the Company’s product sales, these criteria are met at the time the product is shipped; however, occasionally title passes later or earlier than shipment due to customer contracts or letter of credit terms. If at the outset of an arrangement the Company determines the arrangement fee is not, or is presumed not to be, fixed or determinable, revenue is deferred and subsequently recognized as amounts become due and payable and all other criteria for revenue recognition have been met. Taxes collected from customers and remitted to governmental authorities are recorded on a net basis and are excluded from revenue. The Company enters into sales arrangements that may provide for multiple deliverables to a customer. These arrangements may include software and non-software components that function together to deliver the products’ essential functionality. The Company identifies all goods and/or services that are to be delivered separately under the sales arrangement and allocates revenue to each deliverable based on relative fair values. Fair values are generally established using reliable third-party objective evidence, or management’s best estimate of selling price, including prices charged when sold separately by the Company. In general, revenues are separated between hardware, integration and installation services. The allocated revenue for each deliverable is then recognized using appropriate revenue recognition methods. On January 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers, as amended, and created by ASU 2014-09, Revenue from Contracts with Customers. See Note 19 - New Accounting Pronouncements (Issued But Not Yet Adopted) for further discussion regarding the impact of the adoption on the Company’s revenue recognition accounting policies.
Revenue Recognition, Returns and Allowances	Net sales are presented net of returns and allowances. Returns and allowances are calculated and recorded as a percentage of revenue based upon historical returns.
Revenue Recognition, Freight Policy	Net sales include sales of products and billed freight related to product sales. Freight has not historically comprised a material component of Net sales.
Product Shipping Costs	Product Shipping Costs Product shipping costs are expensed as incurred and are included within Cost of sales.
Research and Development	Research and Development The Company invests in research to support development of new products and the enhancement of existing products and services. Expenditures for research and development by the Company were $13.0 million in 2017, $13.4 million in 2016 and $14.0 million in 2015, and are included within SEG&A expenses.
Stock-Based Compensation Plans	Stock-Based Compensation Plans The Company has various stock-based compensation plans, described more fully in Note 13 – Stock-Based Compensation. Stock-based compensation expense is recorded net of estimated forfeitures in the Company’s Consolidated Statements of Operations. The Company estimates the forfeiture rate based on historical forfeitures of equity awards and adjusts the rate to reflect changes in facts and circumstances, if any. The Company revises its estimated forfeiture rate if actual forfeitures differ from its initial estimates.
Income Taxes	Income Taxes We file a consolidated U.S. federal income tax return for Federal Signal Corporation and its eligible domestic subsidiaries. Our non-U.S. subsidiaries file income tax returns in their respective local jurisdictions. We account for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax benefit carryforwards. Deferred tax assets and liabilities at the end of each period are determined using enacted tax rates expected to apply to taxable income in the period in which the deferred tax liability or asset is expected to be settled or realized. A valuation allowance is established or maintained when, based on currently available information and other factors, it is more likely than not that all or a portion of a deferred tax asset will not be realized. Accounting standards on accounting for uncertainty in income taxes address the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the consolidated financial statements. Under the guidance on accounting for uncertainty in income taxes, we may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The guidance on accounting for uncertainty in income taxes also outlines de-recognition and classification, as well as interest and penalties on income taxes. As discussed in Note 8 – Income Taxes, the consolidated financial statements for the year ended December 31, 2017 include the Company’s provisional estimates of the impact of the 2017 Tax Act, in accordance with SAB 118. The Company expects to adjust the provisional amounts throughout the measurement period as the Company’s calculations are refined and additional interpretive guidance becomes available.
Litigation Contingencies	Litigation Contingencies The Company is subject to various claims, including pending and possible legal actions for product liability and other damages, and other matters arising in the ordinary course of the Company’s business. The Company believes, based on current knowledge and after consultation with counsel, that the outcome of such claims and actions in the aggregate will not have an adverse effect on the Company’s financial position or results of operations. However, in the event of unexpected future developments, it is possible that the ultimate resolution of such matters, if unfavorable, could have a material adverse effect on the Company’s results of operations. Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable. In the event that estimates or assumptions of contingent losses are different from actual results, adjustments are made in subsequent periods to reflect more current information.
Business Combinations	The acquisition is being accounted for in accordance with ASC 805, Business Combinations. Accordingly, the total purchase price has been allocated to assets acquired and liabilities assumed in connection with the acquisition based on their estimated fair values as of the completion of the acquisition. A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions. The Company’s judgments used to determine the estimated fair value assigned to each class of assets acquired and liabilities assumed, as well as asset lives, can materially impact the Company’s results of operations. As of December 31, 2017, the Company’s purchase price allocation is considered to be final.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Business Description and Basis of Presentation

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 services rendered by the Company are divided into two major operating segments: Environmental Solutions Group and 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. As discussed in Note 15 – Segment Information, the Company’s reportable segments are consistent with its operating segments.

Fiscal period

Our fiscal year ends on December 31. All references to 2017, 2016 and 2015 relate to the fiscal year unless otherwise indicated.

Basis of Presentation and Consolidation

The accompanying consolidated financial statements represent the consolidation of Federal Signal Corporation and its subsidiaries and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in accordance with United States (“U.S.”) generally accepted accounting principles (“GAAP”).

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 (collectively with its subsidiaries, “TBEI”). TBEI is a leading U.S. manufacturer of dump truck bodies and trailers serving maintenance and infrastructure end-markets. The Consolidated Balance Sheet as of December 31, 2017 includes fair values assigned to the assets acquired and liabilities assumed in connection with the acquisition, whereas the Consolidated Statements of Operations for the year ended December 31, 2017 include the post-acquisition operating results of TBEI.

As discussed in Note 8 – Income Taxes, the Tax Cuts and Jobs Act (the “2017 Tax Act”) was enacted on December 22, 2017. The SEC staff has issued Staff Accounting Bulletin No. 118 (“SAB 118”) to provide guidance on the accounting for the tax impact of the 2017 Tax Act. Under SAB 118, a company that has not completed its accounting for the effects of the 2017 Tax Act by its financial reporting deadline may report provisional amounts based on reasonable estimates for items for which the accounting is incomplete. Those amounts will be subject to adjustment during a measurement period of up to one year. The consolidated financial statements for the year ended December 31, 2017 include the Company’s provisional estimates of the impact of the 2017 Tax Act, in accordance with SAB 118.

Intercompany balances and transactions have been eliminated in consolidation. In addition, certain prior year amounts have been reclassified to conform to current year presentation.

Non-U.S. Operations

Assets and liabilities of non-U.S. subsidiaries, other than those whose functional currency is the U.S. dollar, are translated at current exchange rates with the related translation adjustments reported in stockholders’ equity as a component of Accumulated other comprehensive loss. Accounts within the Consolidated Statements of Operations are translated at the average exchange rate during the period. Non-monetary assets and liabilities are translated at historical exchange rates.

Relating to transactions that are denominated in a currency other than the functional currency, the Company incurs foreign currency transaction gains or losses, which are recognized in the Consolidated Statements of Operations as a component of Other (income) expense, net. For the year ended December 31, 2017, the Company realized foreign currency transaction gains of $1.3 million, whereas in the years ended December 31, 2016 and 2015, the Company incurred foreign currency transaction losses of $0.1 million and $1.5 million, respectively.

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. Actual results could differ from those estimates.

Cash Equivalents

The Company considers all highly liquid investments with a maturity of three months or less, when purchased, to be cash equivalents. The carrying amount of cash and cash equivalents approximates fair value because of the short-term maturity and highly liquid nature of these instruments.

Accounts Receivable

The Company carries accounts receivable at the face amount less an allowance for doubtful accounts for estimated losses as a result of a customer’s inability to make required payments. Management evaluates the aging of the accounts receivable balances, the financial condition of its customers, historical trends and the time outstanding of specific balances to estimate the amount of accounts receivables that may not be collected in the future and records the appropriate provision.

Inventories

The Company’s inventories are valued at the lower of cost or market. Cost is determined using the first-in, first-out method. Included in the cost of inventories are raw materials, direct wages and associated production costs.

Properties and Equipment

Properties and equipment are stated at cost, net of depreciation. Depreciation is recorded using the straight-line method over the estimated useful lives of the assets. Useful lives generally range from eight to 40 years for buildings and three to 15 years for machinery and equipment. Leasehold improvements are depreciated over the shorter of the remaining life of the lease or the useful life of the improvement. Depreciation expense is primarily included as a component of Cost of sales on the Consolidated Statements of Operations, with depreciation expense associated with certain assets used for administrative purposes being presented within Selling, engineering, general and administrative (“SEG&A”) expenses. Depreciation expense, which includes depreciation on rental equipment, was $25.2 million, $18.9 million and $12.0 million in the years ended December 31, 2017, 2016 and 2015, respectively.

Properties and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable.

Rental Equipment

The Company enters into lease agreements with customers related to the rental of certain equipment. All of these leasing agreements are classified as operating leases and are for periods generally not to exceed five years. In accounting for these leases, the cost of the equipment purchased or manufactured by the Company is recorded as an asset and is depreciated over its estimated useful life. Rental income is recognized ratably over the term of the underlying leases.

Rental equipment is depreciated to an estimated residual value on a straight-line basis over the estimated useful lives of the assets and is reviewed for potential impairment whenever an event occurs or circumstances change that indicate the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company first compares non-discounted cash flows expected to be generated by that asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on a non-discounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds fair value. Fair value is determined through various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary.

Rental equipment includes certain equipment that is manufactured by the Company and subsequently transferred to the rental fleet, as well as equipment purchased from third-party manufacturers, for the purpose of renting to end-customers. The related cash flow activity associated with these transactions is reflected within operating activities on the Consolidated Statements of Cash Flows.

Goodwill

Goodwill represents the excess of the cost of an acquired business over the amounts assigned to its net assets. Goodwill is not amortized but is tested for impairment at a reporting unit level on an annual basis or when an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. The Company performed its annual goodwill impairment test as of October 31, 2017.

In testing the goodwill of its reporting units for potential impairment, the Company applies either a qualitative test, or a two-step quantitative test, in accordance with Accounting Standards Codification (“ASC”) 350, Intangibles — Goodwill and Other.

A qualitative approach is applied when the Company concludes that it is not “more likely than not” that the fair value of a reporting unit is less than its carrying value. In this situation, the Company would not be required to perform the two-step impairment test described below.

The first step in the quantitative two-step approach is used to identify potential impairment, by comparing the fair value of a reporting unit with its carrying amount, including goodwill. If the fair value of a reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and the second step of the impairment test is unnecessary. If the carrying amount of a reporting unit exceeds its fair value, the second step of the goodwill impairment test is performed to measure the amount of impairment loss, if any. The second step compares the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. If the carrying amount of reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. The Company generally determines the fair value of its reporting units using two valuation methods: the “Income Approach — Discounted Cash Flow Analysis” method, and the “Market Approach — Guideline Public Company Method.”

Under the “Income Approach — Discounted Cash Flow Analysis” method, the key assumptions consider projected sales, cost of sales and operating expenses. These assumptions were determined by management utilizing our internal operating plan, including growth rates for revenues and operating expenses and margin assumptions. An additional key assumption under this approach is the discount rate, which is determined by reviewing current risk-free rates of capital and current market interest rates and by evaluating the risk premium relevant to the business segment. If our assumptions relative to growth rates were to change, our fair value calculation may change, which could result in impairment.

Under the “Market Approach — Guideline Public Company Method,” the Company identified several publicly traded companies, which we believe have sufficiently relevant similarities to our businesses. For these companies, the Company used market values to calculate the mean ratio of invested capital to revenues and invested capital to EBITDA. Similar to the income approach discussed above, sales, cost of sales, operating expenses and their respective growth rates are key assumptions utilized. The market prices of the Company’s common stock and other guideline companies are additional key inputs. If these market prices increase, the estimated market value would increase. Conversely, if market prices decrease, the estimated market value would decrease.

The results of these two methods are weighted based upon management’s evaluation of the relevance of the two approaches. Management used a qualitative approach to assess the goodwill of its reporting units for potential impairment in 2017. The Company concluded that it was not “more likely than not” that the fair value of its reporting units were less than their carrying values.

The Company had no goodwill impairments for its continuing operations in 2017, 2016 or 2015. See Note 6 – Goodwill and Other Intangible Assets for a summary of the Company’s goodwill by segment.

On January 1, 2018, the Company adopted Accounting Standards Update (“ASU”) No. 2017-04, Intangibles – Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment, which eliminates the second step of the two-step quantitative approach for testing goodwill for potential impairment. See Note 19 - New Accounting Pronouncements (Issued But Not Yet Adopted) for further discussion.

Intangible Assets

Definite-lived intangible assets are amortized on a straight-line basis over the estimated useful lives and are tested for impairment if indicators exist in a manner similar to that described above for Rental Equipment.

Indefinite-lived intangible assets are tested for impairment on an annual basis at year-end, or more frequently if an event occurs or circumstances change that indicate the fair value of an indefinite-lived intangible asset could be below its carrying amount. In testing the indefinite-lived intangibles assets for potential impairment, the Company applies either a qualitative test, or a quantitative test, in accordance with ASC 350, Intangibles — Goodwill and Other. A qualitative approach is applied when the Company concludes that it is not “more likely than not” that the fair value of the indefinite-lived intangibles are less than their carrying value. A quantitative impairment test consists of comparing the fair value of the indefinite-lived intangible asset with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value.

Management used a qualitative approach to assess its indefinite-lived intangible assets for potential impairment in 2017 and 2016. The Company concluded that it was not “more likely than not” that the fair value of indefinite-lived intangible assets were less than their carrying values.

The Company had no indefinite-lived intangible asset impairments for its continuing operations in 2017 or 2016. See Note 6 – Goodwill and Other Intangible Assets for a summary of the Company’s intangible assets.

Warranty

Sales of many of the Company’s products carry express warranties based on terms that are generally accepted in the Company’s marketplaces. The Company records provisions for estimated warranty, which are included within Cost of sales, at the time of sale based on historical experience. The Company periodically adjusts these provisions to reflect actual experience. Infrequently, a material warranty issue can arise which is beyond the scope of the Company’s historical experience. The Company records costs related to these issues as they become probable and estimable.

The Company also sells optional extended warranty contracts that extend coverage beyond the initial term of the express warranty period. At the time of sale, revenue related to the extended warranty contract is deferred and recognized as income over the life of the contract. As of December 31, 2017 and 2016, deferred revenue associated with extended warranty contracts was $2.9 million and $2.6 million, respectively, and was included within Other current liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Costs under extended warranty contracts are expensed as incurred.

Workers' Compensation and Product Liability Reserves

Workers’ Compensation and Product Liability Reserves

Due to the nature of the Company’s manufacturing and products, the Company is subject to claims for workers’ compensation and product liability in the normal course of business. The Company is self-funded for a portion of these claims. The Company establishes a reserve using a third-party actuary for any known outstanding matters, including a reserve for claims incurred but not yet reported. The amount and timing of cash payments relating to these claims are considered to be reliably determinable given the nature of the claims and historical claim volumes to support the actuarial assumptions and judgments used to derive the expected loss payment patterns. As such, the reserves recorded are discounted using a risk-free rate that matches the average duration of the claims.

The Company has not established a reserve for potential losses resulting from the firefighter hearing loss litigation, with the exception of certain estimated losses that have been recognized related to settlement discussions (see Note 11 – Legal Proceedings). If the Company is not successful in its defense after exhausting all appellate options, it would record a charge for such claims, to the extent they exceed insurance recoveries, when the related losses become probable and estimable.

Pensions

The Company sponsors domestic and foreign defined benefit pension plans. Key assumptions used in the accounting for these employee benefit plans include the discount rate, expected long-term rate of return on plan assets and estimates of future mortality of plan participants.

The weighted-average discount rate used to measure pension liabilities and costs is selected using a hypothetical portfolio of high-quality bonds that would provide the necessary cash flow to match the projected benefit payments of the plans. The discount rate represents the rate at which our benefit obligations could effectively be settled as of the year-end measurement date. The weighted-average discount rate used to measure pension liabilities decreased from 2016 to 2017. See Note 9 – Pensions for further discussion.

The expected long-term rate of return on plan assets is based on historical and expected returns for the asset classes in which the plans are invested.

The Company references the most recent mortality tables and scales published by the Society of Actuaries in determining its estimate of future mortality.

Revenue Recognition

Net sales consist primarily of revenue from the sale of equipment, environmental vehicles, parts, service and maintenance contracts.

The Company recognizes revenue for products when (i) persuasive evidence of an arrangement exists, (ii) delivery has occurred, (iii) the sales price is fixed or determinable and (iv) collection is reasonably assured. A product is considered delivered to the customer once it has been shipped, and title and risk of loss have been transferred. For most of the Company’s product sales, these criteria are met at the time the product is shipped; however, occasionally title passes later or earlier than shipment due to customer contracts or letter of credit terms. If at the outset of an arrangement the Company determines the arrangement fee is not, or is presumed not to be, fixed or determinable, revenue is deferred and subsequently recognized as amounts become due and payable and all other criteria for revenue recognition have been met. Taxes collected from customers and remitted to governmental authorities are recorded on a net basis and are excluded from revenue.

The Company enters into sales arrangements that may provide for multiple deliverables to a customer. These arrangements may include software and non-software components that function together to deliver the products’ essential functionality. The Company identifies all goods and/or services that are to be delivered separately under the sales arrangement and allocates revenue to each deliverable based on relative fair values. Fair values are generally established using reliable third-party objective evidence, or management’s best estimate of selling price, including prices charged when sold separately by the Company. In general, revenues are separated between hardware, integration and installation services. The allocated revenue for each deliverable is then recognized using appropriate revenue recognition methods.

On January 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers, as amended, and created by ASU 2014-09, Revenue from Contracts with Customers. See Note 19 - New Accounting Pronouncements (Issued But Not Yet Adopted) for further discussion regarding the impact of the adoption on the Company’s revenue recognition accounting policies.

Revenue Recognition, Returns and Allowances

Net sales are presented net of returns and allowances. Returns and allowances are calculated and recorded as a percentage of revenue based upon historical returns.

Revenue Recognition, Freight Policy

Net sales include sales of products and billed freight related to product sales. Freight has not historically comprised a material component of Net sales.

Product Shipping Costs

Product shipping costs are expensed as incurred and are included within Cost of sales.

Research and Development

The Company invests in research to support development of new products and the enhancement of existing products and services. Expenditures for research and development by the Company were $13.0 million in 2017, $13.4 million in 2016 and $14.0 million in 2015, and are included within SEG&A expenses.

Stock-Based Compensation Plans

The Company has various stock-based compensation plans, described more fully in Note 13 – Stock-Based Compensation. Stock-based compensation expense is recorded net of estimated forfeitures in the Company’s Consolidated Statements of Operations. The Company estimates the forfeiture rate based on historical forfeitures of equity awards and adjusts the rate to reflect changes in facts and circumstances, if any. The Company revises its estimated forfeiture rate if actual forfeitures differ from its initial estimates.

Income Taxes

We file a consolidated U.S. federal income tax return for Federal Signal Corporation and its eligible domestic subsidiaries. Our non-U.S. subsidiaries file income tax returns in their respective local jurisdictions. We account for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and tax benefit carryforwards. Deferred tax assets and liabilities at the end of each period are determined using enacted tax rates expected to apply to taxable income in the period in which the deferred tax liability or asset is expected to be settled or realized. A valuation allowance is established or maintained when, based on currently available information and other factors, it is more likely than not that all or a portion of a deferred tax asset will not be realized.

Accounting standards on accounting for uncertainty in income taxes address the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the consolidated financial statements. Under the guidance on accounting for uncertainty in income taxes, we may recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The guidance on accounting for uncertainty in income taxes also outlines de-recognition and classification, as well as interest and penalties on income taxes.

As discussed in Note 8 – Income Taxes, the consolidated financial statements for the year ended December 31, 2017 include the Company’s provisional estimates of the impact of the 2017 Tax Act, in accordance with SAB 118. The Company expects to adjust the provisional amounts throughout the measurement period as the Company’s calculations are refined and additional interpretive guidance becomes available.

Litigation Contingencies

The Company is subject to various claims, including pending and possible legal actions for product liability and other damages, and other matters arising in the ordinary course of the Company’s business. The Company believes, based on current knowledge and after consultation with counsel, that the outcome of such claims and actions in the aggregate will not have an adverse effect on the Company’s financial position or results of operations. However, in the event of unexpected future developments, it is possible that the ultimate resolution of such matters, if unfavorable, could have a material adverse effect on the Company’s results of operations. Professional legal fees are expensed when incurred. We accrue for contingent losses when such losses are probable and reasonably estimable. In the event that estimates or assumptions of contingent losses are different from actual results, adjustments are made in subsequent periods to reflect more current information.

Business Combinations

The acquisition is being accounted for in accordance with ASC 805, Business Combinations. Accordingly, the total purchase price has been allocated to assets acquired and liabilities assumed in connection with the acquisition based on their estimated fair values as of the completion of the acquisition. A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions. The Company’s judgments used to determine the estimated fair value assigned to each class of assets acquired and liabilities assumed, as well as asset lives, can materially impact the Company’s results of operations. As of December 31, 2017, the Company’s purchase price allocation is considered to be final.