Income Taxes	9 Months Ended
Sep. 30, 2012
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The effective income tax rate for the three months ended September 30, 2012 and 2011 was 37.8% and 37.8%, respectively. The effective income tax rate for the nine months ended September 30, 2012 and 2011 was 37.9% and 37.6%, respectively. The Company's provision for income taxes differed from the U.S. statutory rate of 35% primarily due to state income taxes, domestic production activities deduction, percentage depletion, nondeductible employee compensation and other permanent differences. As of September 30, 2012, the Company had a gross liability for uncertain income tax benefits of $2.8 million, which, if recognized, would impact the effective income tax rate. There have been no significant changes to the calculation of uncertain income tax benefits during 2012. Consistent with the Company's policy, interest and penalties on income taxes have been recorded as a component of the income tax provision. The Company estimates that it is reasonably possible that the balance of unrecognized income tax benefits as of September 30, 2012 could decrease by a maximum of $2.6 million in the next 12 months due to the expiration of statutes of limitation and audit settlements.

Income Taxes

9 Months Ended

Sep. 30, 2012

The effective income tax rate for the three months ended September 30, 2012 and 2011 was 37.8% and 37.8%, respectively. The effective income tax rate for the nine months ended September 30, 2012 and 2011 was 37.9% and 37.6%, respectively. The Company's provision for income taxes differed from the U.S. statutory rate of 35% primarily due to state income taxes, domestic production activities deduction, percentage depletion, nondeductible employee compensation and other permanent differences.

As of September 30, 2012, the Company had a gross liability for uncertain income tax benefits of $2.8 million, which, if recognized, would impact the effective income tax rate. There have been no significant changes to the calculation of uncertain income tax benefits during 2012. Consistent with the Company's policy, interest and penalties on income taxes have been recorded as a component of the income tax provision. The Company estimates that it is reasonably possible that the balance of unrecognized income tax benefits as of September 30, 2012 could decrease by a maximum of $2.6 million in the next 12 months due to the expiration of statutes of limitation and audit settlements.