Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes On a quarterly basis, the Company estimates the effective tax rate expected to be applicable for the full year and makes changes if necessary based on new information or events. The estimated annual effective tax rate is forecast based on actual historical information and forward-looking estimates and is used to provide for income taxes in interim reporting periods. The Company also recognizes the tax impact of certain unusual or infrequently occurring items, such as the effects of changes in tax laws or rates and impacts from settlements with tax authorities, discretely in the quarter in which they occur. For the three months ended March 31, 2018, the Company recorded income tax benefit of $0.3 million at an effective tax rate of 13.5%. The annual effective tax rate differs from the statutory U.S. Federal tax rate due to the impact of state income taxes and nondeductible compensation. The effective tax rate for the three month period ended March 31, 2018 also includes tax benefits from the release of reserves upon the expiration of statutes of limitation, offset by changes in the state allocation/apportionment as a result of a statutory merger and excess tax expense from stock-based compensation. The decrease in effective tax rate for the three months ended March 31, 2018 as compared to the same period last year was primarily attributed to the reduction of the U.S. corporate tax rate from 35% to 21% as a result of the U.S. tax reform. For the three months ended March 31, 2017, the Company recorded an income tax benefit of $2.5 million at an effective tax rate of 45.5%. The Company’s accounting for the certain elements of the Tax Act was incomplete as of the period ended December 31, 2017, and remains incomplete as of March 31, 2018. However, the Company was able to make reasonable estimates of the effects and, therefore, recorded provisional estimates for these items. In connection with its initial analysis of the impact of the Tax Act, the Company recorded a provisional discrete net tax benefit of $73.5 million in the period ended December 31, 2017. This provisional estimate consists of a net expense of $1.4 million for the one-time transition tax and a net benefit of $74.9 million related to revaluation of deferred tax assets and liabilities, caused by the new lower corporate tax rate. To determine the transition tax, the Company must determine the amount of post-1986 accumulated earnings and profits of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. While the Company was able to make a reasonable estimate of the transition tax, the Company continues to gather additional information to more precisely compute the final amount. Likewise, while the Company was able to make a reasonable estimate of the impact of the reduction to the corporate tax rate, its rate may be affected by other analysis related to the Tax Act, including, but not limited to, the state tax effect of adjustments made to federal temporary differences. Due to the complexity of the new global intangible low-taxed income ("GILTI") tax rules, the company is continuing to evaluate this provision of the Tax Act and the application of ASC 740. Under GAAP, the Company is allowed to make an accounting policy choice to either (i) treat taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the “period cost method"); or (ii) factor in such amounts into a company’s measurement of its deferred taxes (the “deferred method”). The Company’s selection of an accounting policy with respect to the new GILTI tax rules is dependent on additional analysis and potential future modifications to existing structures, which are not currently known. The Company has not made a policy decision regarding whether to record deferred taxes on GILTI. The Company will continue to analyze the full effects of the Tax Act on its Consolidated Financial Statements.

Income Taxes

On a quarterly basis, the Company estimates the effective tax rate expected to be applicable for the full year and makes changes if necessary based on new information or events. The estimated annual effective tax rate is forecast based on actual historical information and forward-looking estimates and is used to provide for income taxes in interim reporting periods. The Company also recognizes the tax impact of certain unusual or infrequently occurring items, such as the effects of changes in tax laws or rates and impacts from settlements with tax authorities, discretely in the quarter in which they occur.

For the three months ended March 31, 2018, the Company recorded income tax benefit of $0.3 million at an effective tax rate of 13.5%. The annual effective tax rate differs from the statutory U.S. Federal tax rate due to the impact of state income taxes and nondeductible compensation. The effective tax rate for the three month period ended March 31, 2018 also includes tax benefits from the release of reserves upon the expiration of statutes of limitation, offset by changes in the state allocation/apportionment as a result of a statutory merger and excess tax expense from stock-based compensation. The decrease in effective tax rate for the three months ended March 31, 2018 as compared to the same period last year was primarily attributed to the reduction of the U.S. corporate tax rate from 35% to 21% as a result of the U.S. tax reform. For the three months ended March 31, 2017, the Company recorded an income tax benefit of $2.5 million at an effective tax rate of 45.5%.

The Company’s accounting for the certain elements of the Tax Act was incomplete as of the period ended December 31, 2017, and remains incomplete as of March 31, 2018. However, the Company was able to make reasonable estimates of the effects and, therefore, recorded provisional estimates for these items. In connection with its initial analysis of the impact of the Tax Act, the Company recorded a provisional discrete net tax benefit of $73.5 million in the period ended December 31, 2017. This provisional estimate consists of a net expense of $1.4 million for the one-time transition tax and a net benefit of $74.9 million related to revaluation of deferred tax assets and liabilities, caused by the new lower corporate tax rate. To determine the transition tax, the Company must determine the amount of post-1986 accumulated earnings and profits of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. While the Company was able to make a reasonable estimate of the transition tax, the Company continues to gather additional information to more precisely compute the final amount. Likewise, while the Company was able to make a reasonable estimate of the impact of the reduction to the corporate tax rate, its rate may be affected by other analysis related to the Tax Act, including, but not limited to, the state tax effect of adjustments made to federal temporary differences. Due to the complexity of the new global intangible low-taxed income ("GILTI") tax rules, the company is continuing to evaluate this provision of the Tax Act and the application of ASC 740. Under GAAP, the Company is allowed to make an accounting policy choice to either (i) treat taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the “period cost method"); or (ii) factor in such amounts into a company’s measurement of its deferred taxes (the “deferred method”). The Company’s selection of an accounting policy with respect to the new GILTI tax rules is dependent on additional analysis and potential future modifications to existing structures, which are not currently known. The Company has not made a policy decision regarding whether to record deferred taxes on GILTI. The Company will continue to analyze the full effects of the Tax Act on its Consolidated Financial Statements.