Basis of Presentation and Principles of Consolidation (Details)	6 Months Ended
Jul. 31, 2018 Divisions	Jul. 31, 2018 segment
Organization, Consolidation and Presentation of Financial Statements Line Items [Line Items]
Number of operating units	3	3
Aerostar Integrated Systems [Member]
Organization, Consolidation and Presentation of Financial Statements Line Items [Line Items]
Joint venture, ownership percentage	75.00%	75.00%

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration