New Accounting Standards (Policies)	9 Months Ended
Sep. 30, 2018
Accounting Policies [Abstract]
New accounting pronouncements not yet adopted	The Company has adopted the following new accounting standards: Revenue Recognition In May 2014, the Financial Accounting Standards Board ("FASB") and the International Accounting Standards Board issued a converged standard on recognition of revenue from contracts with customers, Accounting Standard Update ("ASU") No. 2014-09, Revenue from Contracts with Customers (together with all subsequent amendments, "Topic 606"), which replaced most existing revenue recognition guidance under U.S. GAAP. The core principle of Topic 606 requires companies to reevaluate when revenue is recorded on a transaction based upon newly defined criteria, either at a point in time or over time as goods or services are delivered. Topic 606 requires additional disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and estimates, and changes in those estimates. The Company adopted Topic 606 effective January 1, 2018 using the modified retrospective transition approach. Refer to Note 5: Revenue for the impact the adoption of these standards had on the Company's financial statements and related disclosures. Stock Compensation In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting (Topic 718). The ASU amends the scope of modification accounting for stock-based payment awards. Under the new guidance, modification accounting is required only if the fair value, vesting conditions or classification of the award (as equity or liability) changes as a result of the change in terms. The Company adopted this standard effective January 1, 2018 on a prospective basis, with no material impact on its financial statements or related disclosures. Pension Cost In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (Topic 715). The new guidance is intended to classify costs according to their nature and better align the effect of defined benefit plans on operating income with International Financial Reporting Standards. The ASU also provides additional direction on the components eligible for capitalization. The new guidance is required to be applied retrospectively for the change in statement of operations presentation, while the change in capitalized benefit cost is to be applied prospectively. The Company adopted this standard effective January 1, 2018 on a retrospective basis, reclassifying net periodic pension costs other than service cost to Other income, net. This standard had an immaterial impact on the unaudited condensed consolidated statements of operations for the three and nine months ended September 30, 2018 and 2017. Business Combinations In January 2017, the FASB issued ASU No. 2017-01, Business Combinations: Clarifying the Definition of a Business (Topic 805). The new guidance provides that when substantially all the fair value of the assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the asset is not a business. The Company adopted this standard effective January 1, 2018 on a prospective basis, with no material impact on the Company's financial statements and related disclosures. Cash Flows In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The new guidance is intended to reduce the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The ASU requires the classification of eight specific cash flow issues identified under ASC 230 to be presented as either financing, investing or operating, or some combination thereof, depending upon the nature of the issue. The new guidance is required to be adopted retrospectively for all of the issues identified to each period presented. The Company adopted this standard effective January 1, 2018 on a retrospective basis. As a result of adoption, for the nine months ended September 30, 2017, the Company classified a cash inflow of $85.0 million as investing activities within the unaudited condensed consolidated statement of cash flows, and classified $43.2 million as Non-cash investing activities as disclosed in Note 15: Supplemental Cash Flow Information related to the Company's Accounts Receivable Securitization program (the "A/R Securitization"). Refer to Note 14: Accounts Receivable Securitization for additional information. The other cash flow issues included in ASU No. 2016-15 had an immaterial impact on the statement of cash flows. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The new guidance requires restricted cash to be presented with cash and cash equivalents in the statement of cash flows. The Company’s restricted cash balances are presented in the statement of financial position within Prepaid expenses and other current assets. Under the new guidance, changes in the Company’s restricted cash will be classified as either operating activities or investing activities in the statement of cash flows, depending on the nature of the activities that gave rise to the restriction. The Company adopted this standard effective January 1, 2018 using the retrospective transition method. Intangibles - Internal-Use Software In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40). The ASU clarifies and aligns the accounting for implementation costs for hosting arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company has early adopted this standard effective July 1, 2018 on a prospective basis, with no material impact on its financial statements and related disclosures. The following recently issued accounting standards are not yet required to be reflected in the unaudited condensed consolidated financial statements of the Company: Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (together with all subsequent amendments, Topic 842), which will replace most existing lease guidance under U.S. GAAP when it becomes effective. The new guidance requires a lessee to record a right of use (“ROU”) asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. Companies will recognize expenses for real estate related leases on the statements of operations in a manner similar to current accounting guidance and, for lessors, the guidance remains substantially similar to current U.S. GAAP. In July 2018, the FASB issued two additional amendments that affect the guidance issued in ASU 2016-02 as described in the following updates ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements. The amendments in ASU 2018-10 affect narrow aspects of the guidance issued in ASU 2016-02. The amendments in ASU 2018-11 provide an alternative (and optional) transition method that allows entities to apply the transition provisions in ASU 2016-02 at the adoption date instead of at the earliest comparative period presented in the financial statements. The Company is electing to use the optional transition method. The new guidance is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018, with early adoption permitted. Upon adoption, the Company will not revise comparative financial statements or disclosures. The Company’s current operating lease portfolio is primarily comprised of real estate, motor vehicle and IT equipment leases. Upon adoption, the Company expects to recognize operating lease ROU assets and operating lease liabilities related to operating lease arrangements. The Company is currently evaluating and quantifying the expected adoption impact and expects it to have a significant impact on the condensed consolidated balance sheets due to the recognition of ROU assets and operating lease liabilities. In addition, the Company has made accounting policy elections for certain practical expedients offered by the new guidance, such as the practical expedients to not reassess lease classification, lease term or initial direct costs for the existing lease portfolio, as well as to not separate lease and non-lease components. Furthermore, the Company will utilize the portfolio approach in selecting the discount rate used to discount future minimum lease payments for the calculation of the ROU assets and operating lease liabilities for certain equipment leases. Income Taxes In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The new guidance allows a reclassification from accumulated other comprehensive income to retained earnings for any stranded tax effects resulting from the H.R. 1, Tax Cuts and Jobs Act that was enacted on December 22, 2017. The new guidance is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018. The Company has evaluated the effect of this ASU on its financial statements noting no material impact on its financial statements and related disclosures. Stock Compensation In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting (Topic 718). The ASU supersedes ASC 505-50, Equity-Based Payments to Non-Employees and expands the scope of Topic 718 to include stock-based payments granted to non-employees. Under the new guidance, the measurement date and performance and vesting conditions for stock-based payments to non-employees are aligned with those of employees, most notably aligning the award measurement date with the grant date of an award. The new guidance is required to be adopted using the modified retrospective transition approach and is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures. Additional Accounting Standard Changes In July 2018, the FASB issued ASU 2018‑09, Codification Improvements. The amendments in ASU 2018-09 represent changes to clarify, correct errors in or make minor improvements to the Codification, eliminating inconsistencies and providing clarifications in current guidance. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures. Fair Value In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. The ASU modifies the disclosure requirements in Topic 820 by removing certain disclosure requirements related to the fair value hierarchy, modifying existing disclosure requirements related to measurement uncertainty and adding new disclosure requirements, such as disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and disclosing the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures. Retirement Benefit Plans In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans. The ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2020. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures. Consolidation In October 2018, the FASB issued ASU 2018-17, Targeted Improvements to Related Party Guidance for Variable Interest Entities Consolidation (Topic 810). This ASU amends the guidance surrounding the assessment and consolidation of variable interest entities. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.

The Company has adopted the following new accounting standards:

Revenue Recognition

In May 2014, the Financial Accounting Standards Board ("FASB") and the International Accounting Standards Board issued a converged standard on recognition of revenue from contracts with customers, Accounting Standard Update ("ASU") No. 2014-09, Revenue from Contracts with Customers (together with all subsequent amendments, "Topic 606"), which replaced most existing revenue recognition guidance under U.S. GAAP. The core principle of Topic 606 requires companies to reevaluate when revenue is recorded on a transaction based upon newly defined criteria, either at a point in time or over time as goods or services are delivered. Topic 606 requires additional disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and estimates, and changes in those estimates.

The Company adopted Topic 606 effective January 1, 2018 using the modified retrospective transition approach. Refer to Note 5: Revenue for the impact the adoption of these standards had on the Company's financial statements and related disclosures.

Stock Compensation

In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting (Topic 718). The ASU amends the scope of modification accounting for stock-based payment awards. Under the new guidance, modification accounting is required only if the fair value, vesting conditions or classification of the award (as equity or liability) changes as a result of the change in terms. The Company adopted this standard effective January 1, 2018 on a prospective basis, with no material impact on its financial statements or related disclosures.

Pension Cost

In March 2017, the FASB issued ASU No. 2017-07, Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (Topic 715). The new guidance is intended to classify costs according to their nature and better align the effect of defined benefit plans on operating income with International Financial Reporting Standards. The ASU also provides additional direction on the components eligible for capitalization. The new guidance is required to be applied retrospectively for the change in statement of operations presentation, while the change in capitalized benefit cost is to be applied prospectively. The Company adopted this standard effective January 1, 2018 on a retrospective basis, reclassifying net periodic pension costs other than service cost to Other income, net. This standard had an immaterial impact on the unaudited condensed consolidated statements of operations for the three and nine months ended September 30, 2018 and 2017.

Business Combinations

In January 2017, the FASB issued ASU No. 2017-01, Business Combinations: Clarifying the Definition of a Business (Topic 805). The new guidance provides that when substantially all the fair value of the assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the asset is not a business. The Company adopted this standard effective January 1, 2018 on a prospective basis, with no material impact on the Company's financial statements and related disclosures.

Cash Flows

In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The new guidance is intended to reduce the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The ASU requires the classification of eight specific cash flow issues identified under ASC 230 to be presented as either financing, investing or operating, or some combination thereof, depending upon the nature of the issue. The new guidance is required to be adopted retrospectively for all of the issues identified to each period presented. The Company adopted this standard effective January 1, 2018 on a retrospective basis.

As a result of adoption, for the nine months ended September 30, 2017, the Company classified a cash inflow of $85.0 million as investing activities within the unaudited condensed consolidated statement of cash flows, and classified $43.2 million as Non-cash investing activities as disclosed in Note 15: Supplemental Cash Flow Information related to the Company's Accounts Receivable Securitization program (the "A/R Securitization"). Refer to Note 14: Accounts Receivable Securitization for additional information. The other cash flow issues included in ASU No. 2016-15 had an immaterial impact on the statement of cash flows.

In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The new guidance requires restricted cash to be presented with cash and cash equivalents in the statement of cash flows. The Company’s restricted cash balances are presented in the statement of financial position within Prepaid expenses and other current assets. Under the new guidance, changes in the Company’s restricted cash will be classified as either operating activities or investing activities in the statement of cash flows, depending on the nature of the activities that gave rise to the restriction. The Company adopted this standard effective January 1, 2018 using the retrospective transition method.

Intangibles - Internal-Use Software

In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40). The ASU clarifies and aligns the accounting for implementation costs for hosting arrangements with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company has early adopted this standard effective July 1, 2018 on a prospective basis, with no material impact on its financial statements and related disclosures.

The following recently issued accounting standards are not yet required to be reflected in the unaudited condensed consolidated financial statements of the Company:

Leases

In February 2016, the FASB issued ASU No. 2016-02, Leases (together with all subsequent amendments, Topic 842), which will replace most existing lease guidance under U.S. GAAP when it becomes effective. The new guidance requires a lessee to record a right of use (“ROU”) asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. Companies will recognize expenses for real estate related leases on the statements of operations in a manner similar to current accounting guidance and, for lessors, the guidance remains substantially similar to current U.S. GAAP.

In July 2018, the FASB issued two additional amendments that affect the guidance issued in ASU 2016-02 as described in the following updates ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements. The amendments in ASU 2018-10 affect narrow aspects of the guidance issued in ASU 2016-02. The amendments in ASU 2018-11 provide an alternative (and optional) transition method that allows entities to apply the transition provisions in ASU 2016-02 at the adoption date instead of at the earliest comparative period presented in the financial statements. The Company is electing to use the optional transition method. The new guidance is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018, with early adoption permitted. Upon adoption, the Company will not revise comparative financial statements or disclosures.

The Company’s current operating lease portfolio is primarily comprised of real estate, motor vehicle and IT equipment leases. Upon adoption, the Company expects to recognize operating lease ROU assets and operating lease liabilities related to operating lease arrangements. The Company is currently evaluating and quantifying the expected adoption impact and expects it to have a significant impact on the condensed consolidated balance sheets due to the recognition of ROU assets and operating lease liabilities. In addition, the Company has made accounting policy elections for certain practical expedients offered by the new guidance, such as the practical expedients to not reassess lease classification, lease term or initial direct costs for the existing lease portfolio, as well as to not separate lease and non-lease components. Furthermore, the Company will utilize the portfolio approach in selecting the discount rate used to discount future minimum lease payments for the calculation of the ROU assets and operating lease liabilities for certain equipment leases.

Income Taxes

In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The new guidance allows a reclassification from accumulated other comprehensive income to retained earnings for any stranded tax effects resulting from the H.R. 1, Tax Cuts and Jobs Act that was enacted on December 22, 2017. The new guidance is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018. The Company has evaluated the effect of this ASU on its financial statements noting no material impact on its financial statements and related disclosures.

Stock Compensation

In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation: Improvements to Nonemployee Share-Based Payment Accounting (Topic 718). The ASU supersedes ASC 505-50, Equity-Based Payments to Non-Employees and expands the scope of Topic 718 to include stock-based payments granted to non-employees. Under the new guidance, the measurement date and performance and vesting conditions for stock-based payments to non-employees are aligned with those of employees, most notably aligning the award measurement date with the grant date of an award. The new guidance is required to be adopted using the modified retrospective transition approach and is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.

Additional Accounting Standard Changes

In July 2018, the FASB issued ASU 2018‑09, Codification Improvements. The amendments in ASU 2018-09 represent changes to clarify, correct errors in or make minor improvements to the Codification, eliminating inconsistencies and providing clarifications in current guidance. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2018. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.

Fair Value

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. The ASU modifies the disclosure requirements in Topic 820 by removing certain disclosure requirements related to the fair value hierarchy, modifying existing disclosure requirements related to measurement uncertainty and adding new disclosure requirements, such as disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and disclosing the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.

Retirement Benefit Plans

In August 2018, the FASB issued ASU 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Topic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans. The ASU modifies the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2020. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.

Consolidation

In October 2018, the FASB issued ASU 2018-17, Targeted Improvements to Related Party Guidance for Variable Interest Entities Consolidation (Topic 810). This ASU amends the guidance surrounding the assessment and consolidation of variable interest entities. This ASU is effective for public companies for annual reporting periods and interim periods within those annual periods beginning after December 15, 2019. The Company is currently evaluating the effect, if any, that the ASU will have on its financial statements and related disclosures.