Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three months ended March 31, 2018, income tax expense of $1.1 million primarily represented the U.S. federal and state income tax provision of $1.2 million offset by excess tax benefits associated with stock-based compensation arrangements. For the three months ended March 31, 2017, income tax benefits of $38.0 thousand primarily represents $0.5 million of excess tax benefits associated with stock-based compensation arrangements, mostly offset by the U.S. federal and state income tax provision. The effective tax rate was 22.6% and (3.0)% for the three months ended March 31, 2018 and 2017, respectively. The effective tax rate for the three months ended March 31, 2018 was higher than the U.S. federal statutory rate of 21% primarily as a result of state income taxes and offset by excess tax benefits associated with stock-based compensation arrangements. The effective tax rate for the three months ended March 31, 2017 was lower than the U.S. federal statutory rate of 35% primarily due to $0.5 million of excess tax benefits associated with stock based compensation agreements and includes the related tax impact of any adjustments related to the adoption of ASU 2014-09. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act made broad and significant changes to the U.S. tax code including, but not limited to, a change in the federal rate from 35% to 21%, as well as the requirement to pay a one-time transition tax (“deemed repatriation tax”) on all undistributed earnings of foreign subsidiaries. In accordance with Staff Accounting Bulletin 118 (“SAB 118”), income tax effects of the Tax Act may be refined upon obtaining, preparing, or analyzing additional information during the measurement period and such changes could be material. During the measurement period, provisional amounts may be adjusted for the effects, if any, of interpretative guidance issued after December 31, 2017, by U.S. regulatory and standard-setting bodies.

Income Taxes

For the three months ended March 31, 2018, income tax expense of $1.1 million primarily represented the U.S. federal and state income tax provision of $1.2 million offset by excess tax benefits associated with stock-based compensation arrangements. For the three months ended March 31, 2017, income tax benefits of $38.0 thousand primarily represents $0.5 million of excess tax benefits associated with stock-based compensation arrangements, mostly offset by the U.S. federal and state income tax provision.

The effective tax rate was 22.6% and (3.0)% for the three months ended March 31, 2018 and 2017, respectively. The effective tax rate for the three months ended March 31, 2018 was higher than the U.S. federal statutory rate of 21% primarily as a result of state income taxes and offset by excess tax benefits associated with stock-based compensation arrangements. The effective tax rate for the three months ended March 31, 2017 was lower than the U.S. federal statutory rate of 35% primarily due to $0.5 million of excess tax benefits associated with stock based compensation agreements and includes the related tax impact of any adjustments related to the adoption of ASU 2014-09.

On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “Tax Act”). The Tax Act made broad and significant changes to the U.S. tax code including, but not limited to, a change in the federal rate from 35% to 21%, as well as the requirement to pay a one-time transition tax (“deemed repatriation tax”) on all undistributed earnings of foreign subsidiaries. In accordance with Staff Accounting Bulletin 118 (“SAB 118”), income tax effects of the Tax Act may be refined upon obtaining, preparing, or analyzing additional information during the measurement period and such changes could be material. During the measurement period, provisional amounts may be adjusted for the effects, if any, of interpretative guidance issued after December 31, 2017, by U.S. regulatory and standard-setting bodies.