|
Stock-Based Compensation - Restricted Stock Activity (Details) (Restricted Stock [Member], USD $)
In Millions, except Share data, unless otherwise specified
|
9 Months Ended |
12 Months Ended |
|
Sep. 30, 2012
|
Sep. 30, 2011
|
Dec. 31, 2011
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|
Restricted Stock [Member]
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] |
|
|
|
| Outstanding (in shares) |
271,999 |
|
|
| Granted (in shares) |
377,942 |
|
0 |
| Vested (in shares) |
(178,395) |
|
|
| Forfeited (in shares) |
(15,125) |
|
|
| Outstanding (in shares) |
456,421 |
|
271,999 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward] |
|
|
|
| Outstanding, weighted-average grant date fair value (in dollars per share) |
$ 1.43 |
|
|
| Granted, weighted-average grant date fair value (in dollars per share) |
$ 20.15 |
|
|
| Vested, weighted-average grant date fair value (in dollars per share) |
$ 2.90 |
|
|
| Forfeited, weighted-average grant date fair value (in dollars per share) |
$ 3.79 |
|
|
| Outstanding, weighted-average grant date fair value (in dollars per share) |
$ 16.28 |
|
$ 1.43 |
| Total fair value of shares vested |
$ 3.6 |
$ 2.7 |
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