The amount of liability arising from an inherited contingency (as defined) which has been recognized as of the acquisition date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=84160947&loc=d3e2207-128464

Name:	us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContingentLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies (Details) - Jet Prep Ltd. - USD ($) $ in Thousands	Nov. 30, 2017	Oct. 31, 2017	Jul. 31, 2017
Acquisitions
Assumed contingent obligation		$ 1,138
Recurring basis \| Level 3
Acquisitions
Assumed contingent obligation			$ 1,138
Recurring basis \| Level 3 \| Subsequent event
Acquisitions
Assumed contingent obligation	$ 0