Income Taxes (Notes)

6 Months Ended

Jun. 30, 2019

Income Taxes [Abstract]

Income Tax Disclosure

Income Taxes

Income tax expense during interim periods is based on our estimated annual effective income tax rate plus any discrete items, which are recorded in the period in which they occur. Discrete items include, among others, such events as changes in estimates due to the finalization of tax returns, tax audit settlements, expiration of statutes of limitation, and increases or decreases in valuation allowances on deferred tax assets. Our effective tax rate was 24.5% and 13.4% for the three months ended June 30, 2019 and 2018, respectively. Our effective tax rate was 22.7% and 19.3% for the six months ended June 30, 2019 and 2018, respectively. The higher effective tax rate for the three and six months ended June 30, 2019 was primarily due to favorable adjustments allowed under SAB 118 in the prior year, partially offset with the higher excess tax benefits from increased exercises of stock options in 2019.

Unrecognized Tax Benefits

As of June 30, 2019, the total amount of our unrecognized tax benefits was $1.4 million, and the total amount of our accrued interest was $0.6 million.

The federal statutes of limitations have expired for all tax years prior to 2015, and we are not currently under audit by the IRS. Various state jurisdictions are auditing years 2009 through 2017. There are currently no federal or provincial audits in Canada; however, years subsequent to 2014 remain open and could be subject to examination. It is reasonably possible that the amount of unrecognized tax benefits may change within the next twelve months. However, given the number of years that remain subject to examination and the number of matters being examined, an estimate of the range of the possible increase or decrease cannot be made.