Earnings Per Share - Narratives (Details)	Dec. 31, 2017 $ / shares
Convertible Notes, due 2024 \| Convertible Debt
Antidilutive Securities Excluded from Computation of Earnings Per Share
Warrant exercise price (usd per share)	$ 71.775

Exercise price per share or per unit of warrants or rights outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant