Earnings Per Share The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share data): | | | | | | | | | | | | | | | | | | | | Three Months Ended | | Nine Months Ended | | | September 30, | | September 30, | | | 2018 | | 2017 | | 2018 | | 2017 | Numerator for basic and diluted earnings | | | | | | | | | per share - net income (loss) attributable | | | | | | | | | to common stockholders | | $ | 64,384 |
| | $ | 74,043 |
| | $ | 656,487 |
| | $ | 575,118 |
| | | | | | | | | | Denominator for basic earnings per | | | | | | | | | share - weighted average shares | | 373,023 |
| | 369,089 |
| | 372,052 |
| | 366,096 |
| Effect of dilutive securities: | | | | | | | | | Employee stock options | | 6 |
| | 40 |
| | 12 |
| | 53 |
| Non-vested restricted shares | | 348 |
| | 515 |
| | 464 |
| | 464 |
| Redeemable shares | | 1,096 |
| | 1,096 |
| | 1,096 |
| | 1,281 |
| Employee stock purchase program | | 14 |
| | — |
| | 14 |
| | — |
| Dilutive potential common shares | | 1,464 |
| | 1,651 |
| | 1,586 |
| | 1,798 |
| Denominator for diluted earnings per | | | | | | | | | share - adjusted weighted average shares | | 374,487 |
| | 370,740 |
| | 373,638 |
| | 367,894 |
| | | | | | | | | | Basic earnings per share | | $ | 0.17 |
| | $ | 0.20 |
| | $ | 1.76 |
| | $ | 1.57 |
| Diluted earnings per share | | $ | 0.17 |
| | $ | 0.20 |
| | $ | 1.76 |
| | $ | 1.56 |
|
The Series I Cumulative Convertible Perpetual Preferred Stock was not included in the calculations as the effect of conversions into common stock was anti-dilutive. |