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Stock-based Compensation (Tables) | 6 Months Ended
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Jun. 30, 2012
Weighted-Average Assumptions Used to Estimate Grant Date Fair Values for Stock Options Granted | Treasury yields. Weighted-average assumptions used to estimate the grant date fair values for stock options granted in the three and six month periods ended June 30, 2012 and 2011 follow:
|  | Three Months Ended June 30, |  |  | Six Months Ended June 30, |
|  | 2012 |  |  | 2011 |  |  | 2012 |  |  | 2011 |
Volatility |  |  | 48.86 | % |  |  | 45.82 | % |  |  | 48.85 | % |  |  | 45.97 | %
Expected term (in years) |  |  | 5.00 |  |  |  | 5.00 |  |  |  | 5.00 |  |  |  | 5.00 |
Dividend yield |  |  | 1.22 | % |  |  | 0.64 | % |  |  | 1.21 | % |  |  | 0.67 | %
Risk-free interest rate |  |  | 0.88 | % |  |  | 2.38 | % |  |  | 0.88 | % |  |  | 2.34 | %
Stock Option Activity | Stock option activity from January 1, 2012 to June 30, 2012 follows:
|  | Underlying Shares |  |  | Weighted Average Exercise Price |
Outstanding at January 1, 2012 |  |  | 7,081,295 |  |  | $ | 20.73 |
Granted |  |  | 780,000 |  |  | $ | 16.53 |
Exercised |  |  | (13,300 | ) |  | $ | 14.64 |
Outstanding at June 30, 2012 |  |  | 7,847,995 |  |  | $ | 20.33 |
Exercisable at June 30, 2012 |  |  | 6,548,510 |  |  | $ | 20.64 |
Restricted Stock Activity | Restricted stock activity from January 1, 2012 to June 30, 2012 follows:
|  | Shares |  |  | Weighted Average Grant Date Fair Value |
Non-vested restricted stock outstanding at January 1, 2012 |  |  | 1,213,799 |  |  | $ | 24.13 |
Granted |  |  | 788,650 |  |  | $ | 15.60 |
Vested |  |  | (524,010 | ) |  | $ | 22.16 |
Forfeited |  |  | (51,696 | ) |  | $ | 21.89 |
Non-vested restricted stock outstanding at June 30, 2012 |  |  | 1,426,743 |  |  | $ | 20.22 |
Restricted Stock Unit Activity | Restricted stock unit activity from January 1, 2012 to June 30, 2012 follows:
|  | Shares |  |  | Weighted Average Grant Date Fair Value |
Non-vested restricted stock units outstanding at January 1, 2012 |  |  | 17,501 |  |  | $ | 23.47 |
Granted |  |  | 9,000 |  |  | $ | 14.91 |
Vested |  |  | (7,830 | ) |  | $ | 21.08 |
Forfeited |  |  | — |  |  | $ | — |
Non-vested restricted stock units outstanding at June 30, 2012 |  |  | 18,671 |  |  | $ | 20.35 |
Stock-Settled Performance Units | The total target number of shares with respect to the Stock-Settled Performance Units is set forth below:
|  | 2012 Performance Unit Awards |  |  | 2011 Performance Unit Awards |  |  | 2010 Performance Unit Awards |
Target number of shares |  |  | 192,000 |  |  |  | 144,375 |  |  |  | 178,750 |
Fair value of the Stock-Settled Performance Units | using a Monte Carlo simulation model. The fair value of the Stock-Settled Performance Units is set forth below (in thousands):
|  | 2012 Performance Unit Awards |  |  | 2011 Performance Unit Awards |  |  | 2010 Performance Unit Awards |
Fair value at date of grant |  | $ | 3,065 |  |  | $ | 5,569 |  |  | $ | 3,117 |
Compensation Expense Associated with the Stock-Settled Performance Units | These fair value amounts are charged to expense on a straight-line basis over the performance period. Compensation expense associated with the Stock-Settled Performance Units is shown below (in thousands):
|  | Three Months Ended June 30, |  |  | Six Months Ended June 30, |
|  | 2012 |  |  | 2011 |  |  | 2012 |  |  | 2011 |
Stock-based compensation expense associated with Stock-Settled Performance Units |  | $ | 979 |  |  | $ | 724 |  |  | $ | 1,703 |  |  | $ | 983 |

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- Definition Tabular disclosure of the changes in outstanding nonvested performance-based units. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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