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Earnings Per Share | 12 Months Ended
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Dec. 31, 2011
Earnings Per Share [Abstract] |
Earnings Per Share | 14. Earnings per Share The Company has unvested shares of restricted stock outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.
|  | Year Ended December 31, |
|  | 2011 |  |  | 2010 |  |  | 2009 |
Net income |  | $ | 258,966 |  |  | $ | 221,393 |  |  | $ | 52,995 |
Less: |  |  |  |  |  |  |  |  |  |  |  |
Net income attributable to participating securities |  |  | (2,310 | ) |  |  | (2,230 | ) |  |  | (475 | )
Net income attributable to common shareholders |  | $ | 256,656 |  |  | $ | 219,163 |  |  | $ | 52,520 |
The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:
|  | Year Ended December 31, |
|  | 2011 |  |  | 2010 |  |  | 2009 |
Weighted average common shares—basic |  |  | 65,927,421 |  |  |  | 65,472,875 |  |  |  | 65,323,101 |
Plus incremental shares from: |  |  |  |  |  |  |  |  |  |  |  |
Assumed exercise of options |  |  | 372,737 |  |  |  | 203,789 |  |  |  | 98,289 |
Weighted average common shares—diluted |  |  | 66,300,158 |  |  |  | 65,676,664 |  |  |  | 65,421,390 |
Earnings per share: |  |  |  |  |  |  |  |  |  |  |  |
Basic |  | $ | 3.89 |  |  | $ | 3.35 |  |  | $ | 0.80 |
Diluted |  | $ | 3.87 |  |  | $ | 3.34 |  |  | $ | 0.80 |
Excluded from the computation of diluted earnings per share for the years ended December 31, 2011, 2010 and 2009 are options to purchase 141,335, 433,403 and 536,644 shares of common stock, respectively. These options were outstanding during the periods reported but were excluded because the option exercise price was greater than the average market price of the shares.

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- Definition The entire disclosure for earnings per share. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1252-109256 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 55 -Paragraph 52 -URI http://asc.fasb.org/extlink&oid=6945512&loc=d3e4984-109258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6920599&loc=d3e1278-109256 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.21) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 + Details
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