Income Taxes	9 Months Ended
Sep. 30, 2012
Income Taxes	4. INCOME TAXES The Company, along with its wholly owned subsidiaries, files a consolidated U.S. federal income tax return and separate income tax returns in many states throughout the U.S. The Internal Revenue Service (“IRS”) is currently examining the Company’s 2009 consolidated U.S. federal income tax return. The Company remains subject to U.S. federal examination for the tax years ended on or after December 31, 2009. Additionally, any net operating losses that were generated in prior years and utilized through 2009 may also be subject to examination by the IRS. State income tax returns are generally subject to examination for a period of three to five years after filing of the respective return. The Company’s net deferred tax liability at September 30, 2012 is primarily attributable to differences between book and tax depreciation on property and equipment purchased during the three- and nine-month periods ended September 30, 2012. The Company’s effective tax rate was approximately 43% and 42%, respectively, for the three- and nine-month periods ended September 30, 2012, compared to 38% and 40%, respectively, in the corresponding prior year periods. The Company’s effective tax rate for the three- and nine-month periods ended September 30, 2012 reflects an increase in nondeductible compensation-related expenses. The Company’s effective tax rate for the three- and nine-month periods ended September 30, 2011 includes a favorable benefit related to the federal research and development tax credit for fiscal year 2010 totaling approximately $0.2 million. Legislation extending the research and development tax credit beyond December 31, 2011 has not been enacted.

Income Taxes

9 Months Ended

Sep. 30, 2012

4. INCOME TAXES

The Company, along with its wholly owned subsidiaries, files a consolidated U.S. federal income tax return and separate income tax returns in many states throughout the U.S. The Internal Revenue Service (“IRS”) is currently examining the Company’s 2009 consolidated U.S. federal income tax return. The Company remains subject to U.S. federal examination for the tax years ended on or after December 31, 2009. Additionally, any net operating losses that were generated in prior years and utilized through 2009 may also be subject to examination by the IRS. State income tax returns are generally subject to examination for a period of three to five years after filing of the respective return.

The Company’s net deferred tax liability at September 30, 2012 is primarily attributable to differences between book and tax depreciation on property and equipment purchased during the three- and nine-month periods ended September 30, 2012.

The Company’s effective tax rate was approximately 43% and 42%, respectively, for the three- and nine-month periods ended September 30, 2012, compared to 38% and 40%, respectively, in the corresponding prior year periods.

The Company’s effective tax rate for the three- and nine-month periods ended September 30, 2012 reflects an increase in nondeductible compensation-related expenses. The Company’s effective tax rate for the three- and nine-month periods ended September 30, 2011 includes a favorable benefit related to the federal research and development tax credit for fiscal year 2010 totaling approximately $0.2 million. Legislation extending the research and development tax credit beyond December 31, 2011 has not been enacted.