Equity Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement [Abstract]
Equity compensation expense	$ 29.3	$ 28.4
Stock appreciation rights granted	200,000
Stock appreciation rights granted, weighted average exercise price (per share)	$ 145.25
Performance contingent units	100,000
Shares Granted To Non Employee Directors	8,472
Options exercisable (shares)	1,400,000
Options exercisable, weighted average price (per share)	$ 76.08
Options, remaining term	4 years 1 month 6 days
Compensation cost not yet recognized	$ 26.5
Period for recognition	10 months 24 days

Performance contingent units issued to employees during the period.

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Number of shares granted to non-employee directors during the period.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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-Topic 718
-SubTopic 10
-Section 50
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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Gross number of share options (or share units) granted during the period.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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