Stock-based Compensation - Weighted Average Grant Date Fair Value (Details) - $ / shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Stock Options
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value of options granted during the period (in dollars per share)	$ 24.50	$ 16.44	$ 1.47

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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=6415400&loc=d3e5070-113901

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