Debt - (Exchangeable Senior Debentures) (Details) - Exchangeable Senior Debentures - 1.75% Exchangeable Debentures - Charter	Jun. 18, 2018 $ / shares shares
Debt Instrument [Line Items]
Interest rate	1.75%
Exchangeable ratio	2.6989
Exchangeable price (in dollars per share) \| $ / shares	$ 370.52
Number of shares exchangeable \| shares	1,288,051
Redemption percent	100.00%

Debt Instrument, Exchangeable, Exchangeable Price

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- Definition

Debt Instrument, Exchangeable, Exchangeable Ratio

+ References

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Debt Instrument, Exchangeable, Number Of Equity Instruments

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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