v3.8.0.1

Share-Based Compensation (Tables) | 12 Months Ended
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Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |
Summary of Status of Nonvested Shares | A summary of the status of nonvested shares for the years ended December 31, 2017, 2016 and 2015, is presented below:
|  | Shares |  |  | Weighted Average Grant-Date Fair Value |
Nonvested at January 1, 2015 |  |  | 1,122,410 |  |  | $ | 16.52 |
Granted |  |  | 1,278,329 |  |  |  | 4.87 |
Vested |  |  | (419,222 | ) |  |  | 15.26 |
Canceled |  |  | (246,261 | ) |  |  | 14.30 |
Nonvested at December 31, 2015 |  |  | 1,735,256 |  |  | $ | 8.60 |
Granted |  |  | 1,318,229 |  |  |  | 1.90 |
Vested |  |  | (992,461 | ) |  |  | 7.03 |
Canceled |  |  | (107,960 | ) |  |  | 17.33 |
Nonvested at December 31, 2016 |  |  | 1,953,064 |  |  | $ | 4.39 |
Granted |  |  | 2,343,522 |  |  |  | 2.39 |
Vested |  |  | (902,197 | ) |  |  | 6.73 |
Canceled |  |  | (89,728 | ) |  |  | 5.17 |
Nonvested at December 31, 2017 |  |  | 3,304,661 |  |  | $ | 2.21 |

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- Definition Tabular disclosure of the changes in outstanding nonvested restricted stock 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=96867065&loc=d3e5070-113901 + Details
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