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Share-Based Compensation Share-Based Compensation (Summary of Grants) (Details) - shares | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |  |  |
Three-year performance period ending December 31, | 2017 | 2016 | 2015
Vesting shares, target (net of forfeited) | 99,250 | 85,500 | 78,500
Vesting shares, maximum (net of forfeited) | 186,094 | 160,313 | 176,625

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- Definition Performance vesting restricted stock units, three-year performance period ending, years. + References No definition available. + Details
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- Definition Performance vesting restricted stock units, vesting shares, maximum. + References No definition available. + Details
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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=6415400&loc=d3e5070-113901 + Details
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