| Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] | A reconciliation of the numerators and denominators of the basic and diluted EPS computations is presented below: | | | | | | | | | | | | | | | | | | Three Months Ended | | Nine Months Ended | | September 30, | | September 30, | | 2011 | | 2010 | | 2011 | | 2010 | | (In thousands, except per share amounts) | | (In thousands, except per share amounts) | Amounts attributable to common stockholders: | | | | | | | | Net income: | | | | | | | | Net income — basic | $ | 35,496 |
| | $ | 18,765 |
| | $ | 100,353 |
| | $ | 89,962 |
| After tax interest on convertible debt | 13 |
| | — |
| | 38 |
| | 38 |
| Net income — diluted | $ | 35,509 |
| | $ | 18,765 |
| | $ | 100,391 |
| | $ | 90,000 |
| Weighted average shares (denominator): | | | | | | | | Weighted average shares — basic | 232,917 |
| | 246,214 |
| | 237,037 |
| | 250,762 |
| Stock options | 2,475 |
| | 1,309 |
| | 2,370 |
| | 1,603 |
| Convertible debt | 121 |
| | — |
| | 121 |
| | 121 |
| Weighted average shares — diluted | 235,513 |
| | 247,523 |
| | 239,528 |
| | 252,486 |
| Net income per share: | | | | | | | | Basic | $ | 0.15 |
| | $ | 0.08 |
| | $ | 0.42 |
| | $ | 0.36 |
| Diluted | $ | 0.15 |
| | $ | 0.08 |
| | $ | 0.42 |
| | $ | 0.36 |
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