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Share-Based Payments Share-based Payments - Vesting Criteria for Performance and Phantom Shares (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Increase in BVPS	0.00%	0.00%	5.90%	10.70%	13.30%

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- Definition

Share-based Compensation Arrangement by Share-based Award, Entities That Calculate Net Asset Value Per Share, Percent

+ References

No definition available.

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- References

No definition available.

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