Income Taxes	6 Months Ended
Jun. 30, 2012
Income Taxes [Abstract]
Income taxes [Text Block]	Income Taxes Our income tax provision for interim periods is determined using an estimate of our annual effective tax rate adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate and, if our estimated annual tax rate changes, we make a cumulative adjustment. The 2012 annual effective tax rate is estimated to approximate 40%. Our annual effective tax rate for 2011 was 39.6%. At December 31, 2011, we had unrecognized tax benefits of $1,825, of which $1,260 would affect our effective rate if recognized, and accrued interest expense related to unrecognized benefits of $99. At June 30, 2012, there were no significant changes in the unrecognized benefits, including the amount that would affect our effective tax rate if recognized, or the accrued interest expense related to the unrecognized tax benefits. Unrecognized tax benefits are the differences between a tax position taken, or expected to be taken in a tax return, and the benefit recognized for financial reporting purposes. The amount of income taxes we pay is subject to audit by U.S. federal, state and Canadian tax authorities, which may result in proposed assessments. With the exception of U.S. state jurisdictions, the Company is no longer subject to examination by tax authorities for the years through 2008. During the quarter ended June 30, 2012, we received notice that the Internal Revenue Service has selected for examination the Company's U.S. income tax return for the year ended December 31, 2010. As of June 30, 2012, if certain pending tax matters settle, we believe it is reasonably possible that additional tax payments will be made during the next twelve months within a range of $200 to $300. However, we do not anticipate an increase or decrease in our total uncertain tax positions during the next twelve months that would be material to our financial condition or the results of operations.

Income Taxes

6 Months Ended

Jun. 30, 2012

Income Taxes

Our income tax provision for interim periods is determined using an estimate of our annual effective tax rate adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate and, if our estimated annual tax rate changes, we make a cumulative adjustment. The 2012 annual effective tax rate is estimated to approximate 40%. Our annual effective tax rate for 2011 was 39.6%.

At December 31, 2011, we had unrecognized tax benefits of $1,825, of which $1,260 would affect our effective rate if recognized, and accrued interest expense related to unrecognized benefits of $99. At June 30, 2012, there were no significant changes in the unrecognized benefits, including the amount that would affect our effective tax rate if recognized, or the accrued interest expense related to the unrecognized tax benefits. Unrecognized tax benefits are the differences between a tax position taken, or expected to be taken in a tax return, and the benefit recognized for financial reporting purposes.

The amount of income taxes we pay is subject to audit by U.S. federal, state and Canadian tax authorities, which may result in proposed assessments. With the exception of U.S. state jurisdictions, the Company is no longer subject to examination by tax authorities for the years through 2008. During the quarter ended June 30, 2012, we received notice that the Internal Revenue Service has selected for examination the Company's U.S. income tax return for the year ended December 31, 2010.

As of June 30, 2012, if certain pending tax matters settle, we believe it is reasonably possible that additional tax payments will be made during the next twelve months within a range of $200 to $300. However, we do not anticipate an increase or decrease in our total uncertain tax positions during the next twelve months that would be material to our financial condition or the results of operations.