Acquisition (Intangible Assets) (Details) - Quarton - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Jan. 02, 2019
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 22,200
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 years 9 months 18 days
Trade name
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		900
Finite-Lived Intangible Asset, Useful Life	3 years
Customer relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		7,100
Finite-Lived Intangible Asset, Useful Life	4 years
Backlog
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		12,600
Finite-Lived Intangible Asset, Useful Life	2 years
Proprietary software
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 1,600
Finite-Lived Intangible Asset, Useful Life	3 years

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004

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-Name Accounting Standards Codification
-Topic 350
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-Section 50
-Paragraph 2
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