| 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, | | 2013 | | 2012 | | 2013 | | 2012 | | (In thousands, except per share amounts) | | (In thousands, except per share amounts) | Amounts attributable to common stockholders: | | | | | | | | Net income: | | | | | | | | Net income — basic | $ | 26,779 |
| | $ | 41,062 |
| | $ | 118,015 |
| | $ | 126,163 |
| After tax interest on convertible debt | 13 |
| | 13 |
| | 38 |
| | 38 |
| Net income — diluted | $ | 26,792 |
| | $ | 41,075 |
| | $ | 118,053 |
| | $ | 126,201 |
| Weighted average shares (denominator): | | | | | | | | Weighted average shares — basic | 211,954 |
| | 214,914 |
| | 211,721 |
| | 216,974 |
| Stock options | 4,295 |
| | 3,425 |
| | 4,035 |
| | 3,211 |
| Convertible debt | 121 |
| | 121 |
| | 121 |
| | 121 |
| Weighted average shares — diluted | 216,370 |
| | 218,460 |
| | 215,877 |
| | 220,306 |
| Net income per share: | | | | | | | | Basic | $ | 0.13 |
| | $ | 0.19 |
| | $ | 0.56 |
| | $ | 0.58 |
| Diluted | $ | 0.12 |
| | $ | 0.19 |
| | $ | 0.55 |
| | $ | 0.57 |
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