Stock-Based Compensation Plans - Unrecognized Compensation (Details) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($)
Cash-settled PRSUs
Share-Based Compensation Plans
Total unrecognized compensation cost	$ 1,171
Weighted average recognition period	10 months 24 days
Equity-settled PRSUs
Share-Based Compensation Plans
Total unrecognized compensation cost	$ 37,403
Weighted average recognition period	1 year 10 months 24 days
Options
Share-Based Compensation Plans
Total unrecognized compensation cost	$ 13,273
Weighted average recognition period	1 year 8 months 12 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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

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- Definition

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

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