Income Taxes	3 Months Ended
Mar. 29, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's effective tax rate for the three-month periods ended March 29, 2019 and March 30, 2018 was 18.2% and 12.5%, respectively. The effective tax rate for each period is lower than the statutory tax rate primarily due to the impact of percentage depletion and the research and development credit. Additionally, the effective tax rate for both periods included discrete income tax benefits of $0.9 million, primarily related to excess tax benefits from stock-based compensation in 2019 and Staff Accounting Bulletin No. 118 adjustments in 2018.

Income Taxes

3 Months Ended

Mar. 29, 2019

The Company's effective tax rate for the three-month periods ended March 29, 2019 and March 30, 2018 was 18.2% and 12.5%, respectively. The effective tax rate for each period is lower than the statutory tax rate primarily due to the impact of percentage depletion and the research and development credit. Additionally, the effective tax rate for both periods included discrete income tax benefits of $0.9 million, primarily related to excess tax benefits from stock-based compensation in 2019 and Staff Accounting Bulletin No. 118 adjustments in 2018.