Equity-Based Compensation (Schedule of Number of Awards and Weighted Average Grant Date Fair Value) (Details) - $ / shares	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards (in shares)	132,288	98,482
Weighted average grant date fair value (in USD per share)	$ 33.35	$ 43.05
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards (in shares)	67,055	59,112
Weighted average grant date fair value (in USD per share)	$ 33.35	$ 43.05
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards (in shares)	0	20,000
Weighted average grant date fair value (in USD per share)	$ 0.00	$ 43.05

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).

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

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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).

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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