Equity Compensation Plans - Grant Date Fair Value (Details) - $ / shares |
12 Months Ended | ||
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Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Employee Consultants and Directors Stock Options [Member] | |||
| Stock Option Disclosures | |||
| Weighted average estimated grant date fair value per share | $ 15.05 | $ 8.41 | $ 3.84 |
| Restricted and Perfomance Stock Units [Member] | |||
| Stock Option Disclosures | |||
| Weighted average estimated grant date fair value per share | $ 23.34 | $ 26.24 | $ 8.95 |
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- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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