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Stockholders' Equity (Details) | 3 Months Ended
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Mar. 31, 2019 shares
Restricted Stock and Restricted Stock Units |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of equity instruments other than options granted (in shares) | 1,324,319
Restricted Stock and Restricted Stock Units | Employee |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of equity instruments other than options granted (in shares) | 1,089,871
Award vesting period | 3 years
Restricted Stock and Restricted Stock Units | Board of Directors |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of equity instruments other than options granted (in shares) | 234,448
Award vesting period | 12 years
Performance Shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Number of equity instruments other than options granted (in shares) | 390,896
Performance Shares | Minimum |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Share conversion ratio (in shares) | 0
Performance Shares | Maximum |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Share conversion ratio (in shares) | 2
February 2019 | Performance Shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Performance measurement period | 3 years

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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition The number of grants made 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). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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