Share-Based Compensation (Narrative) (Details) - 2017 Grant [Member] - Performance Based Nonvested Shares [Member]	3 Months Ended
Mar. 31, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards, grant date fair value \| $ / shares	$ 51.85
Award vesting period	3 years
Performance share awards, minimum target percentage	0.00%
Performance share awards, maximum target percentage	200.00%
Performance share awards, shares vesting percentage	150.00%
Performance share awards, shares vesting \| shares	39,075

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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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The current assumption based on the most recent information available shares vesting percentage for performance nonvested equitybased awards.

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The fair value at date of grant for nonvested performance equity based awards during the period.

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Percent of shares earned to the target of equity instruments other than options, the maximum percentage of the range.

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Percent of shares earned to the target for equity instruments other than options, the minimum percentage of the range.

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Shares vesting for performance nonvested equity based awards based on the most recent information available.

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