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Stock-Based Compensation (Tables)
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9 Months Ended |
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Sep. 30, 2013
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| Fair Value of Options Granted Calculated Using Weighted Average Assumptions |
The fair value of options granted during the nine month period ended September 30, 2012 were calculated using the following weighted-average assumptions: | | | | | | | | September 30,
2012 | Options granted | | 46,950 |
| Weighted average exercise price | | $ | 41.27 |
| Weighted-average grant date fair value | | 19.08 |
| | | | Assumptions: | | |
| Expected volatility | | 47.70 | % | Expected term (in years) | | 5.9 |
| Risk-free interest rate | | 1.43 | % | Expected dividend yield | | — |
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Below are the assumptions used in the Monte Carlo calculation: | | | | Expected volatility | 37.1 | % | Expected term (in years) | 3.0 |
| Risk-free interest rate | 0.40 | % | Expected dividend yield | — |
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| Summary of Activity Under Stock Option Plans |
A summary of the activity under our stock option plans as of September 30, 2013 and changes during the three and nine month periods then ended, is presented below:
| | | | | | | | | | | | | | | Options Outstanding | | Weighted- Average Exercise Price Per Share | | Weighted-Average Remaining Contractual Life in Years | | Aggregate Intrinsic Value | Options outstanding at June 30, 2013 | 1,503,873 |
| | $ | 42.26 |
| | 3.7 | | $ | 12,388,067 |
| Options granted | — |
| | — |
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| Options exercised | (461,081 | ) | | 38.94 |
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| Options forfeited | (13,617 | ) | | 42.43 |
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| Options outstanding at September 30, 2013 | 1,029,175 |
| | 43.75 |
| | 3.9 | | 16,452,670 |
| Options exercisable at September 30, 2013 | 831,692 |
| | 45.32 |
| | 3.2 | | 12,038,245 |
| Options vested or expected to vest at September 30, 2013* | 1,023,251 |
| | 43.78 |
| | 3.9 | | 16,320,237 |
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* In addition to the vested options, we expect a portion of the unvested options to vest at some point in the future. Options expected to vest are calculated by applying an estimated forfeiture rate to the unvested options. | | | | | | | | |
Options
Outstanding | | Weighted-
Average
Exercise Price
Per Share | Options outstanding at December 31, 2012 | 1,765,947 |
| | $ | 40.58 |
| Options granted | — |
| | — |
| Options exercised | (712,321 | ) | | 36.04 |
| Options forfeited | (24,451 | ) | | 39.49 |
| Options outstanding at September 30, 2013 | 1,029,175 |
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Performance-Based Restricted Stock [Member]
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| Restricted Stock Activities |
| | | | | Performance-Based Restricted Stock Awards | Non-vested awards outstanding at December 31, 2012 | 73,458 |
| Awards granted | 48,660 |
| Stock issued | (33,538 | ) | Awards forfeited | (15,222 | ) | Non-vested awards outstanding at September 30, 2013 | 73,358 |
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Time Based Restricted Stock [Member]
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| Restricted Stock Activities |
| | | | | Time-Based Restricted Stock Awards | Non-vested awards outstanding at December 31, 2012 | 115,139 |
| Awards granted | 152,380 |
| Stock issued | (7,136 | ) | Awards forfeited | (24,492 | ) | Non-vested awards outstanding at September 30, 2013 | 235,891 |
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Deferred Stock Units [Member]
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| Restricted Stock Activities |
| | | | | Deferred Stock Units | Awards outstanding at December 31, 2012 | 30,150 |
| Awards granted | 16,800 |
| Stock issued | (15,400 | ) | Awards outstanding at September 30, 2013 | 31,550 |
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