Fair Value Measurements - Level 3 Reconciliation (Details) - Vencore Holding Corp. and KGS Holding Corp. - Equity securities - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liability balance, beginning period	$ 10,216	$ 6,600	$ 6,819
Net changes in valuation	277	3,616	(219)
Transfers in/or out of level 3	0	0	0
Liability balance, period end	$ 10,493	$ 10,216	$ 6,600

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

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- Definition

Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy.

+ References

No definition available.

+ Details

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- Definition

Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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