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Share-Based Payments - Restricted Share Units Issued to Non-employee Directors (Details) - Restricted Share Units | 12 Months Ended
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Dec. 31, 2018 shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Outstanding (in shares) | 362,572
Management |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 108,455
Vested (in shares) | (96,510)
Forfeited (in shares) | 4,957
Outstanding (in shares) | 6,988
Grants 2016 |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 328,550
Vested (in shares) | (186,862)
Forfeited (in shares) | 82,728
Outstanding (in shares) | 58,960
Grants 2016 | Non-Employee Directors |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 24,456
Vested (in shares) | (21,352)
Forfeited (in shares) | 3,104
Outstanding (in shares) | 0
Grants 2016 | Chairman |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 10,952
Vested (in shares) | (10,952)
Forfeited (in shares) | 0
Outstanding (in shares) | 0
Grants 2017 |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 200,021
Vested (in shares) | (62,433)
Forfeited (in shares) | 37,035
Outstanding (in shares) | 100,553
Grants 2017 | Non-Employee Directors |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 22,230
Vested (in shares) | (20,377)
Forfeited (in shares) | 1,853
Outstanding (in shares) | 0
Grants 2017 | Chairman |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 8,892
Vested (in shares) | (8,892)
Forfeited (in shares) | 0
Outstanding (in shares) | 0
Grants 2018 |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 228,251
Vested (in shares) | 0
Forfeited (in shares) | 25,192
Outstanding (in shares) | 203,059
Grants 2018 | Non-Employee Directors |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 29,024.7678018576
Vested (in shares) | (24,187.306501548)
Forfeited (in shares) | 0
Outstanding (in shares) | 4,838
Grants 2018 | Chairman |
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items] |
Granted (in shares) | 12,899.8968008256
Vested (in shares) | (10,749.914000688)
Forfeited (in shares) | 0
Outstanding (in shares) | 2,150

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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. + 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)(1)(iv)(3) -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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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + 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)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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