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Equity-Based Compensation (Schedule of Number of Awards and Weighted Average Grant Date Fair Value) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards (in shares)	0	25,000	0
Weighted Average Grant DAte Fair Value (in USD per share)	$ 0.00	$ 12.85	$ 0.00
Deferred stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards (in shares)	10,255	10,170	11,945
Weighted Average Grant Date Fair Value (in USD per share)	$ 35.96	$ 34.42	$ 29.30
Common shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards (in shares)	2,113	2,034	3,185
Weighted Average Grant Date Fair Value (in USD per share)	$ 35.50	$ 34.42	$ 29.30
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards (in shares)	116,174	133,548	141,982
Weighted Average Grant Date Fair Value (in USD per share)	$ 36.61	$ 36.56	$ 25.44
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards (in shares)	135,929	108,748	0
Weighted Average Grant Date Fair Value (in USD per share)	$ 33.63	$ 42.72	$ 0.00

X

- 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

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued 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

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-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

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- Definition

Gross number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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