|6 Months Ended
Jun. 30, 2019
|Income Tax Disclosure [Abstract]
We are subject to U.S. federal, state and international income taxes. We are generally no longer subject to federal, state, or international income tax examinations by tax authorities for years before 2015 with few exceptions. Due to the potential for resolution of state and foreign examinations, and the expiration of various statutes of limitations, it is reasonably possible that our gross unrecognized tax benefit balance may change within the next twelve months by a range of $0 to $4.4 million.
Effective Tax Rate
Our effective income tax rate is 23.3% for the three months ended June 30, 2019 compared to 13.7% for the three months ended June 30, 2018. Our effective income tax rate is 12.2% for the six months ended June 30, 2019 compared to 18.0% for the six months ended June 30, 2018. Our second quarter 2018 tax rate was favorably impacted by a settlement with tax authorities of uncertain tax positions related to the 2016 and 2017 tax years. Our effective tax rate is lower for the six months ending June 30, 2019 as compared to 2018 due to permanent tax differences resulting from the accrual for losses associated with certain legal proceedings and investigations related to the 2017 cybersecurity incident. We computed second quarter and year-to-date income taxes for 2019 using the discrete method, applying the actual year-to-date effective tax rate to our pre-tax loss. We believe that this method yields a more reliable income tax calculation for the period due to the uncertainty associated with the estimate of our annual domestic pre-tax book income due to the ongoing litigation, claims, and government investigations related to the 2017 cybersecurity incident.