Stock-Based Compensation Plans - unrecognized compensation expense (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Cash-settled PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 383
Weighted average recognition period	1 year
Equity-settled PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 31,283
Weighted average recognition period	1 year 8 months 12 days
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 4,068
Weighted average recognition period	2 years 9 months 18 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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+ References

No definition available.

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