COMMITMENTS AND CONTINGENCIES (Details) $ in Millions			12 Months Ended
	Jan. 31, 2019 USD ($)	Sep. 08, 2017 USD ($)	Dec. 31, 2018 claim
Pending Litigation
Loss Contingencies [Line Items]
Pending litigation cases | claim			0
Denver Transit Installation of Constant Wireless Crossings | Threatened Litigation | Subsidiaries
Loss Contingencies [Line Items]
Alleged damages		$ 36.8
Asbestos Related Cases | Settled Litigation
Loss Contingencies [Line Items]
Arbitration decisions | claim			2
Subsequent Event | Positive Train Control Patents | Siemens Industry, Inc. | Settled Litigation
Loss Contingencies [Line Items]
Damages award to plaintiff	$ 5.6
Subsequent Event | End of Train Patents | Siemens Industry, Inc. | Settled Litigation
Loss Contingencies [Line Items]
Damages award to plaintiff	$ 1.1