Income Taxes	9 Months Ended
Sep. 30, 2017
Income Taxes	(3) Income Taxes The provisions for income taxes for both the 2017 and 2016 thirty-nine-week periods were based on estimated annual effective income tax rates of 37.8% and 38.1%, respectively, adjusted for discrete events, such as benefits resulting from disqualifying dispositions of the Company’s common stock by employees who obtained the stock through exercises of incentive stock options. The effective income tax rates for the 2017 and 2016 thirty-nine-week periods were 34.5% and 37.6%, respectively. The effective income tax rate for the 2017 thirty-nine week period was lower than the statutory federal income tax rate primarily as a result of federal domestic production activities deductions and research and development credits recognized as discrete items during the thirteen-week period ended September 30, 2017, partially offset by the effect of state taxes and the meals and entertainment exclusion. The effective income tax rate for the 2016 thirty-nine-week period was higher than the statutory federal income tax rate primarily as a result of state taxes and the meals and entertainment exclusion. During the first fiscal quarter of 2017, the Company adopted ASU 2016-09, as further described in footnote 11. As required by ASU 2016-09, the Company recognized $868,000 of excess tax benefits on stock-based awards in its provision for income taxes in the thirty-nine-week period ended September 30, 2017.

(3) Income Taxes

The provisions for income taxes for both the 2017 and 2016 thirty-nine-week periods were based on estimated annual effective income tax rates of 37.8% and 38.1%, respectively, adjusted for discrete events, such as benefits resulting from disqualifying dispositions of the Company’s common stock by employees who obtained the stock through exercises of incentive stock options. The effective income tax rates for the 2017 and 2016 thirty-nine-week periods were 34.5% and 37.6%, respectively. The effective income tax rate for the 2017 thirty-nine week period was lower than the statutory federal income tax rate primarily as a result of federal domestic production activities deductions and research and development credits recognized as discrete items during the thirteen-week period ended September 30, 2017, partially offset by the effect of state taxes and the meals and entertainment exclusion. The effective income tax rate for the 2016 thirty-nine-week period was higher than the statutory federal income tax rate primarily as a result of state taxes and the meals and entertainment exclusion.

During the first fiscal quarter of 2017, the Company adopted ASU 2016-09, as further described in footnote 11. As required by ASU 2016-09, the Company recognized $868,000 of excess tax benefits on stock-based awards in its provision for income taxes in the thirty-nine-week period ended September 30, 2017.