Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2016
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 12 – 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, 2015, and should be read in conjunction with those consolidated financial statements and the notes thereto. As discussed in Note 15 – Discontinued Operations, on January 29, 2016, the Company completed the sale of its Bronto Skylift^® business (“Bronto”) that represented its Fire Rescue Group. The consolidated financial statements for all periods presented have been recast to present the operating results of previously divested or exited businesses as discontinued operations, including the Fire Rescue Group. See Note 15 – Discontinued Operations for further details. In addition, as discussed in Note 2 – Acquisitions, on June 3, 2016, the Company completed the acquisition of substantially all of the assets and operations of Joe Johnson Equipment, Inc. and Joe Johnson Equipment (USA), Inc. (collectively, “JJE”), a Canadian-based distributor of maintenance equipment for municipal and industrial markets. The Condensed Consolidated Balance Sheet as of September 30, 2016 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, 2016 include the post-acquisition operating results of JJE. 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. In addition, certain prior year amounts have been reclassified to conform to the current year presentation. These include adjustments to present the Fire Rescue Group as a discontinued operation, as well as certain reclassifications made to prior-year balance sheet information to conform to the current-year presentation, after giving effect to the JJE acquisition. 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 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. 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 Company expects to apply the “modified retrospective” method of adoption, and is continuing to evaluate the impact that the adoption of this guidance will have on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, Interest – Imputation of Interest (Subtopic 835-30), Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs be presented in the balance sheets as a direct deduction from the carrying amount of the related debt liability. The new requirement is effective for fiscal years beginning on or after December 15, 2015, and for interim periods within those fiscal years. Retrospective presentation is required for all comparable periods presented. The Company’s adoption of this guidance on January 1, 2016 did not have a material impact on its consolidated financial statements. In July 2015, the FASB issued ASU No. 2015-15, Interest – Imputation of Interest (Subtopic 855-30), Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements, which presents the SEC staff’s opinion, in response to ASU No. 2015-03, that debt issuance costs associated with line-of-credit arrangements may be deferred, presented as an asset, and subsequently amortized ratably over the respective term, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. The effective date of this guidance, and the expected impact upon adoption, is consistent with that discussed above with respect to ASU No. 2015-03. The Company’s adoption of this guidance on January 1, 2016 did not have a material impact on its 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 March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting, which impacts amounts recorded in the statements of operations, the classification of awards as equity or liability on the balance sheets, and the classification of related activities on the statement of cash flows. The ASU requires that all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) be recognized as income tax expense or benefit in the income statement and are to be recognized regardless of whether the benefit reduces taxes payable in the current period. The tax effects of exercised or vested awards are to be treated as discrete items in the reporting period in which they occur. The Company may now elect to account for award forfeitures as they occur rather than as part of the compensation expense as the awards are vesting. The requirements for withholding now allow withholding at the maximum statutory tax rate of the beneficiary’s jurisdiction. On the statement of cash flows, excess tax benefits are to be classified under operating activities and shares withheld for tax-withholding purposes are to be classified as a financing activity. These new requirements and options are effective for fiscal years beginning on or after December 15, 2016. Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value are to be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Amendments related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement are to be applied retrospectively. Amendments requiring recognition of excess tax benefits and tax deficiencies in the income statement are to be applied prospectively. An entity may elect to apply the amendments related to the presentation of excess tax benefits on the statement of cash flows using either a prospective transition method or a retrospective transition method. 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. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments should be applied using a retrospective transition method to each period presented. If this approach is impracticable, the amendments would be applied prospectively as of the earliest date practicable. The Company is currently evaluating the impact that the adoption of this guidance will have on its consolidated financial statements but does not expect it will have a material impact on the Company’s historical cash flow presentation. 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 the acquisition of JJE are considered preliminary as of September 30, 2016 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, 2015, with the exception of the following accounting policies associated with the acquisition of substantially all of the assets and operations of JJE: 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 5 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 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 Condensed Consolidated Statements of Cash Flows. The rental income associated with this activity, which is included as a component of net sales on the Condensed Consolidated Statements of Operations, was $6.4 million and $2.2 million for the three months ended September 30, 2016 and 2015, respectively, and $12.1 million and $6.1 million for the nine months ended September 30, 2016 and 2015, respectively. 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. The impairment test consists of comparing the fair value of the indefinite-lived intangible asset, determined using the relief from royalty method, with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value.

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 12 – 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, 2015, and should be read in conjunction with those consolidated financial statements and the notes thereto. As discussed in Note 15 – Discontinued Operations, on January 29, 2016, the Company completed the sale of its Bronto Skylift^® business (“Bronto”) that represented its Fire Rescue Group. The consolidated financial statements for all periods presented have been recast to present the operating results of previously divested or exited businesses as discontinued operations, including the Fire Rescue Group. See Note 15 – Discontinued Operations for further details.

In addition, as discussed in Note 2 – Acquisitions, on June 3, 2016, the Company completed the acquisition of substantially all of the assets and operations of Joe Johnson Equipment, Inc. and Joe Johnson Equipment (USA), Inc. (collectively, “JJE”), a Canadian-based distributor of maintenance equipment for municipal and industrial markets. The Condensed Consolidated Balance Sheet as of September 30, 2016 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, 2016 include the post-acquisition operating results of JJE.

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. In addition, certain prior year amounts have been reclassified to conform to the current year presentation. These include adjustments to present the Fire Rescue Group as a discontinued operation, as well as certain reclassifications made to prior-year balance sheet information to conform to the current-year presentation, after giving effect to the JJE acquisition.

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 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. 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 Company expects to apply the “modified retrospective” method of adoption, and is continuing to evaluate the impact that the adoption of this guidance will have on its consolidated financial statements.

In April 2015, the FASB issued ASU No. 2015-03, Interest – Imputation of Interest (Subtopic 835-30), Simplifying the Presentation of Debt Issuance Costs, which requires that debt issuance costs be presented in the balance sheets as a direct deduction from the carrying amount of the related debt liability. The new requirement is effective for fiscal years beginning on or after December 15, 2015, and for interim periods within those fiscal years. Retrospective presentation is required for all comparable periods presented. The Company’s adoption of this guidance on January 1, 2016 did not have a material impact on its consolidated financial statements.

In July 2015, the FASB issued ASU No. 2015-15, Interest – Imputation of Interest (Subtopic 855-30), Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements, which presents the SEC staff’s opinion, in response to ASU No. 2015-03, that debt issuance costs associated with line-of-credit arrangements may be deferred, presented as an asset, and subsequently amortized ratably over the respective term, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. The effective date of this guidance, and the expected impact upon adoption, is consistent with that discussed above with respect to ASU No. 2015-03. The Company’s adoption of this guidance on January 1, 2016 did not have a material impact on its 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 March 2016, the FASB issued ASU No. 2016-09, Compensation – Stock Compensation (Topic 718), Improvements to Employee Share-Based Payment Accounting, which impacts amounts recorded in the statements of operations, the classification of awards as equity or liability on the balance sheets, and the classification of related activities on the statement of cash flows. The ASU requires that all excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards) be recognized as income tax expense or benefit in the income statement and are to be recognized regardless of whether the benefit reduces taxes payable in the current period. The tax effects of exercised or vested awards are to be treated as discrete items in the reporting period in which they occur. The Company may now elect to account for award forfeitures as they occur rather than as part of the compensation expense as the awards are vesting. The requirements for withholding now allow withholding at the maximum statutory tax rate of the beneficiary’s jurisdiction. On the statement of cash flows, excess tax benefits are to be classified under operating activities and shares withheld for tax-withholding purposes are to be classified as a financing activity. These new requirements and options are effective for fiscal years beginning on or after December 15, 2016. Amendments related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value are to be applied using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Amendments related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement are to be applied retrospectively. Amendments requiring recognition of excess tax benefits and tax deficiencies in the income statement are to be applied prospectively. An entity may elect to apply the amendments related to the presentation of excess tax benefits on the statement of cash flows using either a prospective transition method or a retrospective transition method. 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. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments should be applied using a retrospective transition method to each period presented. If this approach is impracticable, the amendments would be applied prospectively as of the earliest date practicable. The Company is currently evaluating the impact that the adoption of this guidance will have on its consolidated financial statements but does not expect it will have a material impact on the Company’s historical cash flow presentation.

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 the acquisition of JJE are considered preliminary as of September 30, 2016 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, 2015, with the exception of the following accounting policies associated with the acquisition of substantially all of the assets and operations of JJE:

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 5 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 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 Condensed Consolidated Statements of Cash Flows. The rental income associated with this activity, which is included as a component of net sales on the Condensed Consolidated Statements of Operations, was $6.4 million and $2.2 million for the three months ended September 30, 2016 and 2015, respectively, and $12.1 million and $6.1 million for the nine months ended September 30, 2016 and 2015, respectively.

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. The impairment test consists of comparing the fair value of the indefinite-lived intangible asset, determined using the relief from royalty method, with its carrying amount. An impairment loss would be recognized for the carrying amount in excess of its fair value.