| Nine months ended September 30, | Year Ended December 31, | ||||||||||||||||||
| 2012 | 2011 | 2010 | 2009 | 2008 | |||||||||||||||
| Fixed Charges: | |||||||||||||||||||
| Interest expense (1) | $ | 11,874 | $ | 15,304 | $ | 12,233 | $ | 1,141 | $ | 3,978 | |||||||||
| Amortized premiums, discounts and capitalized expenses related to indebtedness (2) | 1,004 | 1,291 | 937 | 300 | 280 | ||||||||||||||
| Estimate of the interest within rental expense (3) | 12,770 | 18,396 | 15,957 | 17,128 | 17,791 | ||||||||||||||
| Total Fixed Charges | $ | 25,648 | $ | 34,991 | $ | 29,127 | $ | 18,569 | $ | 22,049 | |||||||||
| Earnings: | |||||||||||||||||||
| Pre-tax income from continuing operations before income or loss from equity investees (4) | $ | 121,246 | $ | 215,502 | $ | 202,451 | $ | 178,508 | $ | 149,959 | |||||||||
| Fixed Charges | 25,648 | 34,991 | 29,127 | 18,569 | 22,049 | ||||||||||||||
| Distributed income of equity investees (4) | — | — | — | — | — | ||||||||||||||
| Total Earnings | $ | 146,894 | $ | 250,493 | $ | 231,578 | $ | 197,077 | $ | 172,008 | |||||||||
| Ratio of Earnings to Fixed Charges | 5.7 | 7.2 | 8.0 | 10.6 | 7.8 | ||||||||||||||
| (1) Interest expense consists of interest on indebtedness. | |||||||||||||||||||
| (2) Represents the amortization of financing costs incurred in connection with the Company's credit agreement and our 7.25% senior unsecured notes. | |||||||||||||||||||
| (3) The proportion of rental expense deemed to be representative of the interest factor is one third. | |||||||||||||||||||
| (4) Equity investees are investments accounted for using the equity method of accounting. | |||||||||||||||||||
