Stock Based Compensation Stock Based Compensation (Unrecognized compensation costs) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Unrecognized compensation cost	$ 11,559
Restricted stock units [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Unrecognized compensation cost	$ 6,440
Weighted average remaining period of expense recognition (in years)	1 year 3 months 18 days
Performance-based restricted stock units [Member]
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Unrecognized compensation cost	$ 5,119
Weighted average remaining period of expense recognition (in years)	1 year 10 months 24 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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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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