Acquisitions - Appraisal Proceedings (Details) - Appraisal Proceedings - Guidance Software Inc. - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Dec. 31, 2017	Aug. 31, 2017
Business Acquisition [Line Items]
Shares outstanding at acquisition (in shares)		1,519,569
Percent of shares outstanding		5.00%
Loss contingency accrual	$ 2.3	$ 10.8
Share price (in dollars per share)		$ 7.10
Payments for legal settlements	$ 8.5

Loss Contingency, Issued and Outstanding Shares at Acquisition

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- Definition

Loss Contingency, Percent of Shares Outstanding

+ References

No definition available.

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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

No definition available.

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

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- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

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