Commitments and Contingencies - Other (Details) $ in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Jan. 31, 2019 USD ($)	Jan. 31, 2019 AUD ($)
Commitments and Contingencies Disclosure [Abstract]
Compulsory acquisition offer		$ 48.0
Proceeds from advances, percentage of total compensation (percent)	90.00%
Proceeds from advances	$ 31.1