Income Tax Expense

6 Months Ended

Jun. 30, 2015

Income Tax Disclosure [Abstract]

Income Tax Expense

The effective tax rates for the three months ended June 30, 2015 and 2014 were 22.5% and 21.2%, respectively. The effective tax rates for the six months ended June 30, 2015 and 2014 were 22.7% and 22.6%, respectively. The change in tax expense is primarily the result of changes in activity levels among jurisdictions with different tax rates.