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Stock-Based Compensation | 9 Months Ended
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Sep. 30, 2017
Share-based Compensation [Abstract] |
Stock-Based Compensation | STOCK-BASED COMPENSATION During the three and nine months ended September 30, 2017, the Company’s stock-based compensation cost was $2.8 million and $8.0 million, respectively, of which the Company capitalized $1.1 million and $3.2 million, respectively, relating to its exploration and development efforts. During the three and nine months ended September 30, 2016, the Company's stock-based compensation cost was $3.0 million and $9.6 million, respectively, of which the Company capitalized $1.2 million and $3.8 million, respectively, relating to its exploration and development efforts. The following table summarizes restricted stock activity for the nine months ended September 30, 2017:
| Number of Unvested Restricted Shares |  | Weighted Average Grant Date Fair Value
Unvested shares as of January 1, 2017 | 613,056 |  |  | $ | 32.90 |
Granted | 870,358 |  |  | 15.15 |
Vested | (399,843 | ) |  | 28.77 |
Forfeited | (74,024 | ) |  | 30.45 |
Unvested shares as of September 30, 2017 | 1,009,547 |  |  | $ | 19.42 |
Unrecognized compensation expense as of September 30, 2017 related to restricted shares was $17.2 million. The expense is expected to be recognized over a weighted average period of 1.61 years.

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- Definition The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -URI http://asc.fasb.org/topic&trid=2228938 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 50 -URI http://asc.fasb.org/subtopic&trid=2208855 + Details
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