REVENUES FROM CONTRACTS WITH CUSTOMERS - Variable Consideration (Details) $ in Millions	12 Months Ended
Jan. 31, 2019 USD ($)
REVENUES FROM CONTRACTS WITH CUSTOMERS
Amounts of unpriced change orders included in transaction prices	$ 18.8
Impact on revenues, changes in estimates of the costs-to-complete active contracts	$ 32.6

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130551-203045

Name:	us-gaap_ContractWithCustomerLiabilityCumulativeCatchUpAdjustmentToRevenueChangeInMeasureOfProgress
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration