REVENUES FROM CONTRACTS WITH CUSTOMERS - Remaining Unsatisfied Performance Obligations (Details) $ in Millions	Apr. 30, 2019 USD ($)
REVENUES FROM CONTRACTS WITH CUSTOMERS
Contract backlog amount	$ 97.9
Contract backlog (as percent)	100.00%

Percentage of remaining performance obligation to total remaining performance obligation not recognized as revenue.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130556-203045

Name:	us-gaap_RevenueRemainingPerformanceObligationPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant