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Dividends and Earnings Per Share - Dilutive Effect (Details) - shares | 12 Months Ended | 56 Months Ended
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2017
Earnings per share |  |  |  |
Accrued Dividend Equivalent Units | 3,097 |  |  | 3,097
Restricted Stock Units |  |  |  |
Earnings per share |  |  |  |
Granted, Units |  |  |  | 259,065
Equity Plan | Restricted Stock Units |  |  |  |
Earnings per share |  |  |  |
Granted, Units | 10,000 | 100,553 | 0 | 259,065
Accrued Dividend Equivalent Units | 3,097 |  |  | 3,097

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- References No definition available. + 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://www.xbrl.org/2003/role/presentationRef -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=96867065&loc=d3e5070-113901 + Details
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