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Employee Incentive Plans, Unrecognized Compensation Cost (Details) $ in Millions | 9 Months Ended
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Sep. 30, 2017 USD ($)
Non-vested common shares and restricted stock units |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Unrecognized Gross Compensation Costs (in millions of dollars) | $ 9.6
Expected Period (in years) Over Which the Remaining Gross Compensation Costs Will Be Recognized | 2 years 7 months
TSR-Based Performance Shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Unrecognized Gross Compensation Costs (in millions of dollars) | $ 5.6
Expected Period (in years) Over Which the Remaining Gross Compensation Costs Will Be Recognized | 1 year 8 months
CP-Based Performance Shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Unrecognized Gross Compensation Costs (in millions of dollars) | $ 6.1
Expected Period (in years) Over Which the Remaining Gross Compensation Costs Will Be Recognized | 2 years 1 month
EVA-Based Performance Shares |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Unrecognized Gross Compensation Costs (in millions of dollars) | $ 1.5
Expected Period (in years) Over Which the Remaining Gross Compensation Costs Will Be Recognized | 2 years 5 months

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- Definition Unrecognized cost of unvested share-based compensation awards. + 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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