Segment Reporting (Revenues and Operating Earnings Based on Originating Location) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
Segment Reporting Information [Line Items]
Revenues	$ 499.1	$ 411.3
Aerospace Solutions Group
Segment Reporting Information [Line Items]
Revenues	388.1	347.5
Aerospace Solutions Group | Domestic
Segment Reporting Information [Line Items]
Revenues	386.1
Aerospace Solutions Group | Foreign
Segment Reporting Information [Line Items]
Revenues	2.0
Energy Services Group
Segment Reporting Information [Line Items]
Revenues	111.0	$ 63.8
Energy Services Group | Domestic
Segment Reporting Information [Line Items]
Revenues	$ 111.0