Income Taxes

6 Months Ended

Jun. 30, 2019

Income Tax Disclosure [Abstract]

Income taxes

Income taxes

Our effective tax rate for the three and six months ended June 30, 2019 was 24.9% and 24.1%, respectively, compared to 20.8% and 21.9%, respectively, for the same periods in 2018. Our effective tax rate for the three and six months ended June 30, 2019 differs from the federal statutory rate primarily due to state income tax expense on current year earnings and tax benefits for equity compensation. For the same periods in the prior year, our effective tax rate differed from the federal statutory rate primarily due to state income tax expense on current year earnings, tax benefits due to Internal Revenue Service acceptance in 2018 of an accounting method change applicable to the 2017 tax year, energy credits, and tax law changes.

At June 30, 2019 and December 31, 2018, we had deferred tax assets, net of deferred tax liabilities and valuation allowance, of $224.1 million and $275.6 million, respectively. The accounting for deferred taxes is based upon estimates of future results. Differences between estimated and actual results could result in changes in the valuation of deferred tax assets that could have a material impact on our consolidated results of operations or financial position. Changes in existing tax laws could also affect actual tax results and the realization of deferred tax assets over time.

Unrecognized tax benefits represent the difference between tax positions taken or expected to be taken in a tax return and the benefits recognized for financial statement purposes. We had $22.4 million and $30.6 million of gross unrecognized tax benefits at June 30, 2019 and December 31, 2018, respectively. Additionally, we had accrued interest and penalties of $6.0 million and $5.8 million at June 30, 2019 and December 31, 2018, respectively. It is reasonably possible within the next twelve months that our gross unrecognized tax benefits may decrease by up to $8.4 million, excluding interest and penalties, primarily due to potential audit settlements.